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Friday, 20 March 2020 19:38

Coronavirus and JMG Porsche

Over the years we at JMG Porsche have had to deal with many and varied struggles.

Recessions and financial crashes and now a very serious pandemic, Coronavirus or as it is also known, COVID-19 (Which sounds much more exciting for the media machine!) and we are still open!

You know JMG Porsche, we are a common-sense based company, we do not get involved in hype or try to be trendy, we believe in having our feet firmly attached to the ground and always try to make common-sense decisions, so you can be assured that we will keep an eye on the advice and legislation of the government, but also reading between the lines, and using our own common sense to maintain our service to our customers, while also keeping customers and JMG employees safe.

Since the virus landed in the UK, we have had daily meetings on the subject of the virus and making sure we are doing exactly what we need to be doing, to continue operations and maintain sensible levels of health security.

As it stands at the time of writing this, we are still open, and here are a number of measures we are taking to ensure safety to you and our health, but also to increase your convenience during this time of mass inconvenience.

Car collection and delivery service

We have always offered free car collection and delivery for customers living in the right local postcodes. But now that Coronavirus is now gripping the nation, schools have closed leaving some customers stranded at home, some are self-isolating and unable to leave the house, and some are just juggling family, community and work commitments, making it difficult to bring their cars to us, and indeed to get home afterwards. With this in mind, it seems sensible for us to extend our collection and delivery service nationwide! Obviously this will carry some financial costs, but prices will be tailored to a case by case basis dependent on the volume of work being performed and of course your address.

When collecting your car, we need not have physical contact with you, we can call you when we are outside but away from your door, you can then put the keys outside of your front door, and then retreat inside for us to collect the keys. We will be wearing gloves, we will disinfect/cleanse your keys, apply protective coverings to hand controls and the seat, and will continue to take precautions before we return your car.

When we return your car, we again call you to let you know we are outside, and once we are finished with touching your car, we will remove all coverings, and set off a decontaminating device within your car and lock it. This device is disposable and designed to release a car-friendly disinfecting spray, fogging the interior, which will not leave a residue in the car, and will leave it decontaminated and smelling of either "Citrous" or "linen".

If you would like your car collected and delivered back to you, following the service, diagnosis or repairs, please call us to discuss logistics and a tailored price.

Dropping your car off in person during office hours.

When dropping off your car in person, there is not even any need to enter our building, you can call us and a member of staff will exit the building, wearing fresh disposable surgical gloves, and will be able to retrieve your keys from you, which if you choose can be via leaving the keys on the roof of the car, our staff will come out, perform a quick body check of your car, and collect your keys. Once you have seen this be done, from a distance if you prefer, you can then retreat home, safe in the knowledge that you have not had to interact with anyone.

You can also call us to discuss the work to be done, and we can take pictures if requested of anything you might usually ask to see in person during the process of repairs. So again, there is no need for anyone to be within your safety bubble.

Once your car is checked in, we will apply protective coverings, which are disposable, to the seat, steering wheel, gear lever, handbrake lever and other controls that we may need to touch. But beyond this, we will always be wearing gloves regardless.

Dropping off your car in person out of office hours.

Our business is covered by numerous CCTV cameras which can be monitored 24 hours a day, and the industrial estate has CCTV and 24-hour security, so if you do drop off your car outside of office hours, the front car park area is extremely safe and secure.

Once your car is locked, please put your keys through our letterbox, along with a note with details of your name and the car registration. Once the keys are through our letterbox, they are covered by our RedCare security alarm system, so if anyone tried to get your keys once posted, will set off the alarm system which will trigger Police response (The Dorset Police divisional headquarters are about one mile away so it would not take long!)

However, your car gets to us, we will work in ways to reduce risks of contamination both of your car, and of our staff.

Staff members will be applying protective coatings to all internal hand controls, and levers that we might touch while the car is here. In addition, we will be wearing protective gloves while working on your car and changing them as we switch between cars.

We will also remain in contact with you by email, SMS messages and by telephone.

Paying us without even entering our building!

We are currently encouraging customers to make payments to us using their card over the phone.

Once work is complete, we will email a copy of your invoice to you, so you can read it and ensure you are happy with it, and then call us, where we can take payment from your credit or debit card over the telephone.

Or we can offer a small discount for you paying by bank transfer.

We believe this is a common-sense way to reduce your exposure to risks. Debit and credit card terminals are used by many people, and even though ours will be cleaned on a regular basis and ideally between every transaction, they offer many discreet locations for the nasty virus to lurk.

Decontamination of your car prior to collection.

Before you collect your Porsche from us following us working on it, it will be cleaned externally, vacuumed internally, and chemically decontaminated internally, even into the vents and heater/air conditioning system!

We have always believed in washing and vacuuming cars prior to collection, it not only allows you to get into a nicely cleaned car as part of the service but now we are going even further!

The wash now involves a snow foam method, which coats the entire exterior of your car in a detergent foam which will cling to the car, soaking into grime for much longer than the 20 seconds we are advised to wash our hands for. But more than this, the foam is specifically chosen to be extremely friendly to your Porsche exterior, but also to be extremely aggressive towards anything biological which should not be there!

We request that you let us know when you are 15 minutes away from collecting your car, so we can park your car in the front car park, remove protective coverings and deploy our car interior decontamination device. This is an aerosol-based device, which releases a disinfecting fog within the cabin, and into every nook and cranny, without leaving any residue, stains and the only odour afterwards is one of citrus fruit or linen.

Once decontaminated, we will not touch your car again, which is why we would ask you to warn us of your arrival, as it is not healthy to enter the car while this device is in operation!

This service is free of charge, however, if we need to decontaminate your car more than once, due to a failure for you to arrive when expected, then there will be a minor charge for this.

Everything is under daily review.

We are constantly checking the latest advice from the government and authorities, so our policy is under constant review during this unusual set of circumstances, with daily meetings of directors and staff to re-assess the situation.

At the moment there is no danger of us being forced to close, and if we were, as a company offering breakdown services to many doctors, we would campaign to remain open throughout the crisis, even if that is just to complete the cars currently in progress and get them back to their owners, even if their owners are self-isolating or under some kind of lockdown.


Q - I am self-isolating as someone with, or potentially with Coronavirus, will you still look at my car?

A - Of course we will, but we would appreciate you informing us of your situation. Just as we can decontaminate your car prior to it being back in your care, we can decontaminate it prior to our staff entering it, as well as ensuring our staff have personal protective equipment to ensure they are not exposed to risks of contracting the virus, such as wearing an overkill protective respirator when collecting the car and until it is decontaminated.

Q - I am self-isolating, can I still use my Porsche?

A - At the moment, unless the laws are changed to outlaw this, such as they are in the "Isle of Man" if you are self-isolating if you decide to take your car for a drive, as long as you keep the windows closed, and the roof up in the case of convertible cars, you will not cause any spread of your potential infection. Going out for a drive, as long as you do not get out of the car to interact with anyone, could give a welcome release from going stir crazy at home, and in our opinion, you will not pose any risk to other members of society.

Q - I would like to book my car in for next week or even next month, is that possible? Will you be open?

A - We are obviously are not in control of the lawmakers, but unless we absolutely have to close through force of law, it is our current plan to remain open, so yes, please feel free to book your car in.

Q - My Porsche has suffered a breakdown, but I do not have an appointment can I bring it to you or have it recovered to you?

A - At JMG Porsche we have always had a policy of keeping some of our schedule unbooked to be able to deal with breakdowns or emergency repairs. Even if your MOT has lapsed and you need to performing urgently, we will try to help. So no, for any emergency repairs, or urgent attention needed, you can usually have your car brought to us, or we can even arrange recovery for it, without an appointment.

If you have any questions, we welcome them, please call us on 01202 488800 or email This email address is being protected from spambots. You need JavaScript enabled to view it. where we will endeavour to not only answer your questions but also to remain flexible and help wherever we can.

Published in JMG News
Monday, 17 December 2018 17:25

Boxster & Cayman Servicing and Repairs

Your Boxster or Cayman is in the best of hands at JMG Porsche, where even with servicing we go beyond the factory schedule.

The factory schedule for many models called for a service every two years, which was fine when the car was new and to make the car last beyond the factory warranty without issue. However we strongly recommend that all models are serviced annually, alternating between a minor and a major service each year. Click here and read our article for more information.

Here is a breakdown of our servicing.

Boxster and Cayman Minor service Includes

  • Pre service test drive (JMG Additional included item)

  • Fault code analysis

  • Replacement of the pollen filter

  • Replacement of the oil filter and engine oil (Porsche approved oil)

  • Factory specified inspection of - the vehicle under side, engine compartment, coolant hoses, coolant (level and condition), radiator or radiators, air intake, brake system, brake hoses, brake lines, drive shafts, tyres, locks and latches, electrical equipment, horn, windscreen wiper washing system, power steering and fluid level, lighting system check (including headlights and indicators)

  • JMG Inspection of additional items which are common issues as this model ages (JMG Additional included item)

  • Final test drive to check all major safety, comfort and mechanical systems for correct operation.

  • Final fluid and levels check

  • Dashboard electronic service light reset

  • Courtesy interior vacuum and wash (JMG Additional included item) 

Boxster Major servicing includes

All items from minor servicing, plus...

  • Replacement of the air cleaner element

  • Check condition, lubricate and adjust if required - fuel system, parking brake, clutch, steering gear, tie rod ends, axle joints, running gear, exhaust system, suspension, seat belts, throttle actuation and auxillary drive belt.

  • Numerous additional JMG Specific inspection and adjustments which are model specific, added as the car's get older.

Prices for Boxster and Cayman servicing.

1997 - 2004 Boxster models (Type 986) - Minor service £195 - Major service £275

2005 - 2007 Boxster and Cayman Models (Type 987) - Minor service £275 - Major service £360

2008 - 2011 Boxster and Cayman Models (Type 987 Gen2) - Minor service £290 - Major service £360

2012 - 2016 Boxster and Cayman Models (Type 981) - Minor service £360 - Major service £475


All services are performed with Porsche approved oil and genuine OEM filters.

Upgrade your service to premium Mobil engine oil for only £49.95 extra 


The importance of routine annual servicing.

Routine annual servicing will benefit your car from being inspected by an expert every year, which will certainly mean that many problems are spotted long before they turn into an expensive problem, a simple seal for example, costing only a few pennies, could be all that needs to be spotted and rectified to avoid a complete engine failure.

Beyond this, on more modern models where the servicing is specified by the factory for every two years, there is evidence that that has decreased the long term reliability of components. A good example of this are the engine oil hydraulic components on a Porsche 997 being the same parts as used in a Porsche 996, yet the 996 rarely suffers from variocam solenoid failures, but those of the 997 are frequent and can cost thousands of pounds to repair, just for the sake of regular yearly servicing and oil changes.

Some people only cover a few miles per year and therefore believe their car will not need regular annaul servicing, however this also can cause problems.



We have many menu prices for Porsche repairs of each model which are usually likely to cost more if performed with our hourly rate, call us for a price.

For anything else our repairs hourly rate is £79.95 per hour.


Menu price diagnostic appointment - £159.20 (Two hours)

Porsche cars are especially sophisticated and complicated cars, therefore diagnosis needs to be performed by expert Porsche specialist diagnostic technicians, the cream of the crop, even for what might seem like very simple faults.

With all faults, there will be a problem, such as a bad relay for example, as well as this there will be a cause, perhaps this cause would be what caused the relay to become faulty, which in itself could be abstract or unusual, or could be as simple as age, but it is still important to be reasonably sure of the cause, before new parts are installed, otherwise the new parts will also swiftly expire!

Even with the most expert technicians it is impossible to predict what the fault may be, until we have spent some time both diagnosing what is faulty and what has caused that item to be faulty, so to be professional at what we do, in some cases we may need to spend a longer duration of time with our investigations.

Unfortunately, this can mean that diagnosis can be very time consuming and therefore expensive, as well as difficult to schedule in our busy workshop.

With this in mind we have developed a clinic system for diagnostic visits, where we charge £149.20 for a two hour appointment. During which the following will happen.

  • The customer will be able to talk to the diagnostic technician in person to explain the fault.

  • The diagnostic technician will endeavour to recreate the fault to experience it in person, perhaps including a test drive with the customer.

  • The diagnostic technician will then begin tests to narrow down the fault, which may include using the Porsche diagnostic computers, or even our special diagnostic equipment not available elsewhere, studying the engineering documentation, technical service bulletins as well as running manual tests on or off of a vehicle lift.

  • In the case of the problem being simple, it may even be possible that within this phase the problem may be found, the cause clear and perhaps even a repair made.

  • Once complete, before the two hour appointment is exhausted, the technician will spend time with the customer explaining what he has found, as well as what additional diagnosis may need to be performed, how long that may take, and what potentially could be the causes of the problem, concluding with an appointment made for when the further diagnosis or repairs can be made.

Between the end of this visit and the appointment for continuation of the repairs or diagnosis, the car can be taken away, or left with us by mutual agreement.


Interesting service and repair information for the Boxster and Cayman models.

Service interval - Some models specify a yearly service in the owners handbook, some specify two yearly, now that several years have passed since the first models with two yearly servicing were introduced we have observed that those models are more prone to needing expensive repairs, such as bore failure, valve actuator faults which we are only able to assume is caused by less frequent servicing. We would strongly recommend that all Porsche models are serviced yearly or every 10,000 miles to avoid expensive repairs and to potentially catch issues early, where they may be less expensive to repair.

Engine failures - Not nearly as common as horror stories on the internet would have you believe, but there are still worthwhile ways of avoiding unexpected large engine rebuild costs. One of which is proper servicing by a real Porsche specialist, which may not need cost as much as you think. There are also some ways to avoid unexpected bills by following some of our other advice bellow.

Brake fluid - Did you realise this should be changed every two years? Not doing this can cause problems with expensive parts within your car, such as the ABS pump or any part of the brake hydraulics due to water contamination as the brake fluid actually sucks moisture out of the air (hydroscopic), so even if the car is not used, the brake fluid must be changed every two years!

Water Pump - Often thought of as a part which fails with age, mileage and quite suddenly, leaving you stranded, our expert technicians are used to inspecting these during services, and so may spot tell tale signs of failure long before they become an issue, so saving you from the indignity of being broken down at the side of the road.

IMS Bearing - The famous intermediate shaft bearing (IMS Bearing) is an important bearing within the engine. These can fail on pre 2005 models of Boxster and cause catestrophic damage to the engine, sometimes costing thousands to repair. However there is a better design of bearing available, which our engine specialists at JMG Porsche have developed some cost effective ways to install and remove the risk of this kind of engine failure. Typically, the most cost effective time to replace this bearing with the better design is at the same time as a clutch replacement. However if you do not need a clutch now, or own a tiptronic Boxster, then we can perform this job at any time.

RMS - Rear main seal - Something else you might see horror stories on the internet about, these used to be a real problem and Porsche re designed the part several times to arrive at the current design which is the only one we at JMG Porsche use. Like an IMS Bearing replacement, this is best performed during a clutch change, however on tiptronic models or on cars not needing a clutch, they can be changed at any time.

Transmission services - Not clearly noted by Porsche for when the transmission should be serviced and this vital expensive part of your car should not be overlooked. Just like your engine, the transmission is filled with oil/transmission fluid, which over time degrades. Not only this, but not many realise that many Porsche transmissions also contain a filter, which becomes clogged over time and can starve your transmission of lubrication, causing expensive repairs. We recommend all Porsche transmissions are serviced every 4 years or 40,000 miles, whichever comes soonest.

Air Oil Separator - If your Porsche is producing some smoke, especially when it starts up in the morning, it could be that the air oil separator has failed rather than your whole engine being damaged. This simple device is designed to allow your engine to pass polution regulations and should not cost the earth to replace, at least much less expensive than rebuilding an engine!

Drive Belt - Many of you may have had cars where a drive belt, timing belt or cam belt needs to be changed at a regular interval. Your Porsche model has a belt which should be changed every 4 years. Failure to do so can cause instant overheating, loss of power steering and damage to the engine very suddenly. We recommend you have this changed at least every 4 years.

Heavy clutch? - A heavy feeling clutch which is stiff to use is not normal on a Porsche and often a sign that the clutch has almost worn out. Ignoring this can cause further damage, such as to the dual mass flywheel and clutch fork.

Alarm system - At JMG Porsche we are experts of all Porsche security systems and have reverse engineered all the various control units. This not only means we can program new alarm control units and keys to your car, just as the main dealer can, but in some cases we can repair your old alarm control unit and keys, or in some cases recover your old keys to be used on the new alarm control unit, which is a service unique to JMG.

Alarm system causes - In most cases the cause of alarm control unit failure is water damage, we can perform modifications to your Porsche model to help mitigate the chances of this happening to your Porsche.


Monday, 18 December 2017 14:30

Importance of yearly servicing

The importance of routine annual servicing.


Everyone knows that a car needs to be serviced to keep it reliable and to avoid expensive repairs.

However there are two occasions where Porsche owners may believe that their car does not need servicing every year.


But the service book says to service the car every two years.”

Many more modern Porsche models specify two yearly servicing in the service book for the car, which is fine for the first four years of the car's life, as the factory are focussed on the car lasting beyond the duration of the factory warranty. Beyond this, you are on your own.. However we will explain later in this article why this can be a big mistake.


But I only cover a few miles per year.”

Because often servicing is specified in the service book as yearly or every other year, but also at a set mileage, many people believe that if they have only covered 200 miles in a year, that the car does not need a service.

However, chemistry within your engine will turn your oil from a protecting fluid, into a toxic chemical soup which can literally eat your engine components alive.


Engine oil over two years old is where chemistry becomes your enemy!

Once you start your engine with fresh engine oil a process begins where the oil will be contaminated with hydrocarbons from the combustion process, even if the engine was only started once, when the engine oil has been mixed with these chemical compounds for a year, the oil will have broken down and the chemicals will have become more toxic to your engine.

The engine oil will have begun life as a relatively neutral compound, neither overly acidic or caustic. However hydrocarbons from combustion, entering the oil past your piston rings will have begun to change all of that, some of these compounds only need moisture to become even more toxic.

You may not realise but when your engine is stopped and cooled, any moisture from humidity in the air will collect and condense within the engine and drain back into the oil, more humid air will enter the engine and this also will condense. This moisture will kick start other chemical reactions within the engine oil and especially reacting with the combustion by products within the no longer fresh engine oil.

When the engine is next started, fresh chemical reactions begin, additives within the oil can be destroyed and the chemical make up of the oil within the engine changes further.


This vicious circle is worse with infrequently used cars, as regular use will cause the moisture to evaporate away and have less time to damage the molecules and composition of the engine oil.

This problem is also made worse the longer the engine oil is within the engine, one year is fine, but two years can mean that the engine oil has become very toxic for your engine.

Another problem with the changing chemical composition of the engine oil is that these processes can produce sludge, varnishes and other unwelcome byproducts within your engine.


The proof.

A good example of this are the late Porsche 996 and early 997 engines which share the same engine oil controlled hydraulic solenoids, in the 996 models with yearly servicing these rarely fail, however in the 997 models with two yearly servicing they fail on a reasonably regular basis, likewise with the cam followers. Repairing these consequences of the two yearly services, even when that is what the service book calls for, can costs thousands of pounds to repair!

Beyond the engine oil, many other items are lubricated during a service, and these lubricants are designed to be re-applied every year at most, which means without regular lubrication the components will fail. A good example are the gear selector cables on Boxster and 911 models, on the pre 2005 models (with yearly servicing) they rarely fail, however on the post 2005 models (with two yearly servicing) we now find we need to replace them relatively frequently.

Another example would be that every 996 or 997 which has suffered bore scoring issues that we have seen, has been one specified with two yearly servicing!


A conspiracy by the manufacturers?

Some would say this is a conspiracy by the manufacturers to make more money on selling parts and repairs out of warranty.

However we believe they are just trying to make the car's seem more attractive to new car buyers due to low servicing costs.

Whatever the reason, the person who suffers is usually the person who owns the car when it is over 5 years old, by which time the damage of infrequent servicing are already done and getting worse every time the pattern continues.


There are many other consequences of not having your Porsche serviced every year.

Another good example might be suspension bushes, if replaced as soon as they become aged or worn, the cost of repairs is just the bushes and labour. However if they are left until they have symptoms obvious to the driver the damage will also be to the tyres, which we all know on a Porsche are not cheap!

The solution to this is to always try to buy a car which has been serviced every year, even if the model is specified by the factory to be serviced every two years, and never buy a car which has had the servicing deferred because it had not covered many miles between services.

Beyond this, even if the car has skipped services in the past, whatever model it is, have it serviced every year and follow the advice of your Porsche specialist of any additional items which need replacement, such as drive belts, water-pumps, coolant, brake fluid, brakes etc.. Not following this advice could cost you thousands of pounds if neglected.

A service is a service wherever it is performed, right?

A last note, it is important who you choose to service your Porsche. Any garage can change the oil in your Porsche, but a true specialist will check much more during the process and know what to look for.

Checking the old engine oil for consistency, smell and inspecting it under a powerful light will warn of many other potential issues with the car, such as early signs of bearing failure, fuel pressure, fuel injector condition and much more, all much cheaper to repair before their issues become more chronic and expensive.

Expert eyes will be looking for common problems with each model and year that an average garage will miss, which will cost you much more money later, if not spotted now.


What else to do?”

Other than all this, enjoy your Porsche, we have found conclusively over the years that the cars which are not used on a regular basis and not driven hard, will suffer more acute problems than those driven hard on a regular basis.. Think of your Porsche as a race horse, it needs to stretch it's legs on a regular basis, otherwise it will stop being a race horse and turn into a stiff old nag!

Tuesday, 03 October 2017 19:58

Porsche 996 and 986 Boxster Alarm primer

The Porsche security system in the Porsche Boxster 986 models (up to 2004) and the 996 models upto 2005 can be problematic. When faulty they can cause all kinds of strange behaviour, including winding windows up and down, the car not locking or unlocking with the remote or in some cases with the key even, as well as the car failing to start or any combination of these problems.

To help the Porsche community get to the bottom of problems they may be experiencing, we have written this 996/986 Security system 101 article.

Q: Do all Boxster 986 and 996 models have a factory fitted alarm and immobiliser?

A: All 986 and 996 models do have an immobilser, nearly all of them have a combined alarm and immobiliser (I am yet to see one of the rare ones which has the immobiliser only)

For the purposes of this security system primer, we will assume that all the 986 and 996 models are the versions with the combined alarm and immobiliser.

Over the last 20 years since we first started repairing the Boxster and 996 models, we have had to replace hundreds of key remotes and alarm control units, the details of the inner workings of both are an undocumented mystery with Porsche releasing very few details for obvious reasons.

Without having the proper Porsche PST2 (Porsche system tester two) official diagnostic computer, or one of the later PIWIS or PIWIS2 computers, normally only available at Porsche main dealers, or super-duber independents like JMG Porsche, a new alarm control unit or key remote can not be programmed to work with your car.

Even with one of these super amazing factory tools, you also need special numbers, unique to each car, to program the new control units, previously only available from the Porsche main dealer network.

By the time that 2015 rolled around, Jon Mitchell at JMG Porsche was getting a little bit frustrated. Previously every single component within a Porsche car he had intimate knowledge of just how it worked, from the software within the control units, through to the the engines and transmissions, what he did not like was that it seemed that there was a lack of information about the Porsche security systems, even through the official main dealer information systems... So he set about reverse engineering them which has unlocked all of their inner secrets, but for security reasons, only some of them will be ever released to the wider public.. Hopefully though, these details with help other Porsche technicians and Porsche owners understand the security systems in these cars a little better.

So, in essence, without giving too much away.. How does the system work?

There are three main elements to the security system.

  • The Key with its key head remote (the black bit on the end of the key with buttons)
  • The Key with its transponder (This is buried in the black plastic remote at the end of the key)
  • The Key alarm and immobiliser control unit, both housed in a black plastic box, under one of the front seats, waiting for a bath (more on this shortly!)

The key remote head buttons, and the circuit board under them, along with a battery, are there to lock the car (also setting the alarm in the process) and to unlock the car (and unsetting the alarm in the process), apart from on some versions opening the front or rear luggage area, or in others opening the roof. This is all they do (in simple terms)

The transponder chip, completely unattached to the alarm remote other than being housed in the same black plastic blob with buttons, does one thing.. When you put the key in the ignition, a form of magic (known as inductive loop technology) causes the transponder to have a quick chat with the immobiliser side of the alarm control unit, causing the immobiliser to in turn have a chat with the engine management system, and allow the car to start.

The combined alarm and immobiliser control unit, sitting under one of the seats, apart from unlocking and locking doors, immobilising the engine, stopping the windows from working, allowing the windows to wind up and down, and in some models controlling what the roof is allowed to do, also has one other mission in life, detect water, and once detected, panic, act confused or even keel over and die.

Now to learn a bit more about what makes the alarm control unit to fail, before we move onto the remote controls and their problems.

Under the left hand seat (in a right hand drive UK spec car) sits the alarm control unit, which also houses the nerve centre of the immobiliser.. It sits in a slight depression of the metal floor of the car, which is a bit of a problem, because any water that makes it's way into the car will find that depression and fill it up, damaging the alarm control unit in the process.

Traditionally, the alarm system at this point, will be kaput.. It may still work a bit, it may be doing some strange things such as partially working, intermittently working or the car might just be acting possessed. The alarm might start going off for no apparent reason, the windows might start rolling up or down without you ever pressing the buttons, you might even come back to your car and find it locked, even though you were sure you had locked it, or the remote controls might stop working.

In the past, a kaput alarm would have had one cure... Drying out the water (if it had not done it anyway), solving the leak (often on Boxsters the roof drains) and replacing the alarm control unit and the key remotes, sometimes this could cost anything from £1500 upwards in parts and labour!

Following reverse engineering the security systems, we can in many cases repair the alarm control units (and the leak) and have you one your way again, without having to buy a new alarm control unit, key remotes and paying for programming, we can even do this remotely by post or courier.

Another solution, but one which is very much not recommended, would be to buy a used alarm control unit, keys and engine management control unit from a breaker.. However, this is a very big false economy, as you will no longer be able to unlock the immobiliser or engine management control unit to program a future alarm remote, which is inevitable, without then needing to buy a new alarm control unit, key remote and engine management system, or buying another set from a breaker and throwing the previous ones away. Not only this, but a Porsche specialist or main dealer will no longer be able to perform some specialist tasks to your systems, such as programming them with new software which is released on a regular basis (Such as for running the new fuels with higher ethanol content, as is happening right now!)

What kills the alarm control units?

Water usually. In particular with Boxster models you can almost garauntee that whenever it rains, we start to get calls from Boxster and 996 owners with either misfires, cars that will not start or car's which are behaving unusually.

Typically with Boxsters, 996 models with sun roofs or targa roofs, blocked drains or poor seals cause water to run often un-noticed under or behind the carpet and end up filling the small wells or depressions in the floor where the alarm control unit lives. Either killing it completely, or even just making it do unusual things such as the alarm going off intermittently, the windows doing odd things, the car not starting (either failing to run, or the starter motor not working) among many other failure modes.

In the rain when we get calls about a 996 or Boxster (or other models) misfiring, it is usually down to cracked coil packs.

Next, the remote controls can play up in a number of ways...

If you find your Boxster or 996 alarm has stopped remotely unlocking and locking the car via the buttons on the remote control, there could be a number of problems causing this apart from a bad alarm control unit.

The Remote Battery.

In the alarm key remote is a small battery, often, replacing the battery will solve problems with the buttons not locking or unlocking the car, try this first. If you have not replaced your batteries in a year or two, they probably need doing anyway!

The Remote control's computer chip has frozen or crashed.

A few years ago Porsche were so swamped with warranty replacements of the key remotes that they issues a technicial service bulletin (TSB) explaining how to reset a remote control which had crashed or frozen, the process is simple..

  1. Remove the battery from the key remote
  2. Insert the battery the wrong way round, flip it, so the writing is facing the other way. Do not worry, this will not damage the remote.
  3. Press the unlock button continuously while jumping on one foot for sixty seconds (Jumping on one foot is optional but helps pass the time and helps with fitness)
  4. Flip the battery back around the right way.
  5. Try the remote control again, if this works you can be sure that the remote had crashed/frozen and you successfully reset it.

The Remote control has become out of sync with the alarm control unit.

Through reverse engineering the software inside the alarm control unit, we were able to de-cypher how the alarm control unit and the key remote talked and how the rolling codes worked.

Rolling codes are not top secret information, they are used in just about every alarm system remote control in the world, both in systems designed by car manufacturers as well as with after-market car alarm system manufacturers. In essence, every time you use the remote control to lock or unlock the car, the alarm system and remote control have a little chat and do not disclose all the details of a very special long number that they both have stored, they just ask one-another mathematical questions about part or parts of the number, and if both of them feel happy about the conversation, they then agree to lock or unlock the car.. Once they have done this, they both take their number and encrypt it slightly to change it for next time, but without ever again disclosing to the other what the new number is.. It should always match as they will have mashed up the number is a very specific way. However, sometimes problems occur.

Potential causes of the alarm system and remote control going out of sync are numerous, they can include the weather, radio interference (such as even a taxi driving past with the driver using a two way radio) or even you being just on the cusp of being close enough or too far away from the car when you used the remote.

In rare cases like this, the key remote or the alarm system may have mashed up it's code to a new version, without the other also doing the same. This is in effect what causes the remote and alarm going out of sync.

Anyway, as we mentioned, at JMG Porsche we reverse engineered the alarm system hardware and software, so discovered a little known and undocumented process to re-sync the alarm control unit and the key remote.. There is a proviso, if the two have gone out of sync by too many steps, the damage has been done and the two will never be able to be sync'ed up again, even with our amazing abilities at JMG Porsche.

The process to re-sync the remote key head is as follows.

  1. Put the key manually into the door lock (it does not matter if it is already locked or unlocked.
  2. Press the lock/unlock button and hold it in.
  3. Turn the key to the lock position and back to the middle position five times and return to the middle position one last time.
  4. Let go of the lock/unlock button.
  5. Press and hold in the lock/unlock button again.
  6. Turn the key to the unlock position and back the middle position five times and return the the middle position again.
  7. Let go of the lock/unlock button.
  8. Press the lock/unlock button in again and hold it in.
  9. Turn the key to the lock position and back to the middle position five times and return to the middle position again.
  10. Take the key out of the door lock and try the buttons.

If the buttons now work, you have successfully re-synced your alarm system control unit and keys! Well done, go and pat yourself on the back and drink a well deserved beer/coffee/tea/vodka (delete as appropriate) while you reflect on how the key remote might have gone out of sync... Are you a persistent key in pocket fiddler? or did you let your young son or daughter play with your keys? If so, stop it! Or at least now you know how to fix it if it happens again.

However, this will only work if the key remote and the alarm control unit have only stepped a couple of steps out of sync with the alarm control unit, if you are a supper "key in pocket fiddler" or your child has played with the buttons to such an extent that the codes have rolled more than a couple of times, then the key may now be so far out of sync, nothing will bring it back.

Faulty Remote Controls

They are pretty robust units really, but even a Porsche key head remote controls can eventually fail, here are some failure modes.

  • Main circuit board failure - This could be as simple as a "dry joint" needing re-soldering, or a crack in the board which may or may not be repairable.
  • Button failure - Usually the buttons fall apart because the plastic outer casings button area cracks, causing the button inside to move slightly sideways, rather than just in and out. These can be repaired with a new or used button soldered into the old ones location, and new upper outer shells are available to fix the actual cause.
  • Water damage - The remote control key heads have a rubber seal, if when you change the battery this is not re-fitted or if it breaks with age, damp gets in and can destroy the remote. Usually you will see water damage on the circuit board.
  • Designed in planned obsolescence - This I feel is a little bit naughty of the designers, or a very simple honest mistake in design. Once the code in the remote has rolled a pre set number of times, after literally hundreds of button presses, it will not be able to roll any more due to how the software was programmed. The alarm system however will continue to roll the code into infinity, so eventually they will go one step out of sync and the love affair between your remote key head and the alarm control system will be over forever.

What can JMG Porsche do to help?

Apart from writing this article so that owners, enthusiasts and even Porsche technicians can understand the system a little better, we have a few things that we can do in house to solve your alarm system problems.

What we and the Porsche main dealers can do, as well as probably a few specialists.

  • Programming a new alarm key head remote to your existing alarm control unit.
  • Programming a new alarm control unit along with new key head remote controls.
  • Diagnosing a problem with the alarm control unit or key remotes.

What we can do that the main dealers can not do and potentially no one else in the world can do in some cases!

  • Repairing and refurbishing your current key head remote
  • Repairing and refurbishing your current alarm control unit
  • Programming a new alarm control unit with your old key remote keys that worked with the old one
  • Re-programming a used second hand alarm control unit to work with your car and your key remotes
  • Re-programming an incorrectly programmed control unit to be a new virgin unit again, or with the correct data (Useful for other Porsche technicians who have hit the wrong button or experienced power failure during programming)
  • Extracting and decoding the unique to your car's Porsche security data needed to program a new control unit, from an old dead control unit
  • Extracting and decoding the unique to your car's Porsche security data when Porsche do not have it available (such as with the RUF manufactured Porsche models where Porsche do not have the right data)
  • Programming a new alarm control unit on the bench, without ever seeing your car in person, we just need your old alarm control unit, keys and ideally your DME (Engine management computer) Which is useful for those who want to save the labour costs of a Porsche technician to remove the old control unit and fit a new one.

What we can not do..

  • Program any random key head remote to your car, it needs to have been previously working with the old control unit at time of failure

What we will not do, even if we can!

  • Send you out a new alarm control unit and key remote for a car with just the chassis number unless you provide adequate proof of ownership (A legal authority document such as a log book/V5 (UK) title deed (USA) and a the address of this document has to match the postal address we will send it to.
  • Educate or pass on what we have learned from reverse engineering the security systems to any third party other than the information on this page. A software engineer knows the decryption routines but does not know what they are for, an electronics engineer knows the methods to extract the required scrambled data but again does not know what the circuit boards do, and only Jon at JMG knows the full process and processes the repairs. Anyone trying to approach Jon asking or probing for more information will result in the Police being informed. No documents, printed or in data form exist to help anyone else crack the system, so unfortunately the exact process will die with Jon.

What can be done to protect a 986 or 996 from the alarm control unit getting water damaged in the first place?

  • Good idea - Getting JMG Porsche to install their 9x6 alarm system drainage port modification to your floor, they let the water out, but do not let it in!
  • Good idea - Getting JMG Porsche to install their 986 improved roof drainage system to your Boxster
  • Good idea - Routinely check your roof drains for leaves and general debris which accumulate there and remove and clean them, or ask your specialist to do this a couple of times a year for you. It only takes half an hour to an hour in labour and can save you a fortune!
  • Bad idea - Fitting a sealed box or bag around the alarm control unit, these rarely are 100% water tight and will often allow water in, but not let it out, so you end up with small amounts of water accumulating over time in the sealed enclosure, but with not enough ventilation for it to evaporate away, until eventually there is enough water to damage the control unit, which can happen in cases where the amount of moisture would not have been enough to cause damage on its own.

And what to never do?

Never, every buy a "set" or "kit" containing an alarm system control unit, DME (engine management computer) and key remotes from a Porsche salvage business and fit them to your car.

  • The software in the DME may not be right for your engine, causing all kinds of unseen problems.
  • The identity of your Porsche will not match the Porsche database IPAS Codes, meaning that you will NOT be able to program new keys without having to buy a new alarm control unit, DME and key remotes, at a massive cost. Which with a used key remote, is very likely to happen at some point, potentially very soon!
  • You will not be able to have your DME reprogrammed over time, such as the roll out of high ethanol fuels which is happening now..
  • Your Porsche identity in your control units will not match your car's actual chassis number, you may encounter insurance problems or even end up in hot water with the Police and have to prove the identity of your Porsche is that of the chassis number, such as via a VIC check, which your Porsche will fail due to chassis number mismatches in the various control units versus the number plates worn and the chassis number stamped into the shell. (There have been a number of Porsche that have ended up on Q plates and a dodgy HPI history due to this kind of problem!


A last amusing fact.

Someone at Porsche decided after the 996 and 986 models that perhaps putting the alarm control unit in a depression in the floor, likely to fill up with water was an especially bad idea, so in the 987 Boxster and Cayman models, as well as the 997 models, they moved it away from the floor level and renamed the system as the Porsche Access System (PAS)..

This was a great idea..

Until someone else at Porsche, potentially looking for a good place to put the new "Rear Body Control Unit" (that was a new feature of these cars), had a eureka moment and decided to put this control unit in this really useful empty place under the seat... So if you own a Porsche 987 Boxster, Cayman or 997 and are wondering why your rear lights are doing odd things (brake lights on all the time, reverse lamps on even when not in reverse) or the roof has an interest in suddenly moving up or down, even if locked in position, snapping control rods in the process, then your rear body control unit has probably flooded in exactly the same way that the old alarm control units used to on the earlier model... That is progress for you!



Saturday, 30 September 2017 11:30

Porsche 944 Cam and Balance belt replacement

This is not going to be an article about how to change your cam and balance belt on a Porsche 944 or 968, this subject has been covered elsewhere on the internet and personally, it is one of those jobs where if you have not been trained to do it, are not experienced in doing it, you should not do it.. An apprentice at JMG Porsche is not allowed to change a 944/968 cam or balance belt until they have their basic first two years of training under their belt, after that they are supervised on the first few and on probation for the first 4 years with them being checked... So in short, get a pro to do it, ideally a specialist with in depth knowledge of the 944 and 968 engines.

Over the years I have often been asked how often they should change their cam and balance belt on their 924S, 944 or 968, and my answer is "Every 4 years" and change the water pump, front engine oil seals, belt tensioners and rollers every 8 years!

The following questions and answers are here to explain why I advise what I advise and is actually a cut and paste from a recent answer by myself as a technical advisor to the Porsche Club of Great Britain, as a response to a question on their forum.

To an extent, the same advice applies to any belt, on any car, so a Boxster, Cayman or Cayenne/Macan/Panamera or 911 (996, 997, 981 or even air cooled cars) which as a whole do not have cam belts, but do have auxiliary drive belts which if they fail will at best leave you stranded, but at worst can damage the engine or even the bodywork of the car (belts at high speeds make a mess!)

Other than not having a balance belt, the Porsche 928 advice would be the same advice as for the 924S, 944 and 968 owners. 

What destroys a belt?
From education training and experience
* Entropy (Everything wants to return to its original component materials) - Very slow
* Oxygen (Oxidises the rubber from the outside inwards, forming cracks eventually, which then allow more oxygen deeper into the belt)
* Wear (Accelerated if the tension is too high or too low)
* Incorrect installation
Who makes the belts for Porsche?
Over the years I have seen the following belts in Genuine Porsche boxes.
* Dayco
* Gates
* Bosch
* Continental
How long can an incorrectly setup or installed belt last?
* As little as a few seconds
* As long as a correctly installed belt
Depends on how incorrectly it has been installed or setup (I have seen many weird things going on in 944 belt covers)
What else accelerates belt degradation?
* Contamination from oil
* Contamination from power steering fluid
* Contamination from coolant
* Contamination from dirt/grit
* Contamination from fuel
* Contamination from plastic dressings
* Contamination from sprays such as WD40
* Ionisation of the air in the cam belt cover
How soon can a correctly tensioned good quality belt without contamination last?
* Soonest I have seen is 5 years with a missing ionisation cap.
* Soonest I have seen with no visible signs of cause - 6 years
* Oldest belt that I have seen break was 26 years old!!!
When would I change the belts on my own 944 fleet?
* Every 5 years without fail and I check inside the cover every year for contamination or issues and always check for leaks every time I drive them.
When would I recommend customers change them?
* Every 4 years (as you might not have your belt, oil seals and leaks checked so often as I do)
How much damage is caused by not changing them?
* Wrecked cylinder head (Valve contacts and bent/detaching valve heads)
* Wrecked pistons (Valve contact, sometimes with valve heads detaching and bouncing around!)
* Wrecked cylinder block (mushroomed out pistons split the bore)
Other advice.
* Change the water pump, tensioners, rollers and front engine oil seals on every second belt change. The water pump can fail through age as well as mileage, as can the seals and tensioners/rollers. Any of these parts can cause the belt to fail.
* Make sure your car has an ionisation cap between the distributor cap and upper front cam belt cover.
This is an important one.
When the 944 was designed, it had a hose that ran between the cam belt cover and air box.. This was to bring fresh air through the belt covers, and remove air which had been ionised by the electrical activity within the distributor cap. There was also a plastic cap between the distributor cap and the cam belt cover, to reduce the amount of contamination of the air within the belt cover with air ionised within the distributor cap.
In about 1988, Porsche eventually go to the bottom of why so many 944s suffered with hydrolocked engines following driving through deep puddles or crossing a river/ford crossing... It turned out that as soon as water was sprayed around the front crank pulley, or the pulley entered water, the water would go into the belt cover and the balance belt would throw this water directly at the vent port which had the hose to the air box.. Once the air box contained a certain amount of water, or you turned a corner, the water would flow through the airflow meter, and get sucked into the engine... Nasty.
Porsche then issued a TSB to say that all Porsche models should have this hose where fitted (important) and a blanking plug fitted (Not so important, I leave them open for ventilation on the advice of my mentor at Porsche).
The problem with this deleted hose, is that without it, it is even more critical to have the ionisation cap installed. They are cheap and available.
That is all :)

Wednesday, 27 September 2017 19:59

Porsche alarms..

At this time of year, JMG Porsche get many more phone calls and emails regarding faults caused by the Porsche factory alarm system, which are often connected to damp weather

Unfortunately the traditional repair is often a new alarm control unit and new key remotes, which can become an extremely expensive repair of between £1000 and £1500. But do not panic, there is an alternative!

At JMG Porsche we spent much of 2015 and 2016 reverse engineering the Porsche alarm system and keys, and we believe that we are potentially the only people in the world, outside of the companies who developed the original systems for Porsche, who understand fully how these systems work. The result is we can not only repair these units, but beyond that we can also save you money by recycling your old keys to be used with your repaired or even new alarm control unit!

If your old control unit can be repaired, we can repair it with new components.

If your old control unit is beyond repair, we can even re-program your old keys into the new control unit (A worldwide first!)

Not only this, for the DIY mechanics out there, but we can even perform these repairs by mail-order, so wherever your car is, we can provide a repair service, or reprogramming of your car, without even needing to see the car!

If you are suffering from any of the following issues, please make sure you get in touch with us first!

* Door windows raising or lowering by themselves

* Alarm system going off for no reason

* The roof trying to move by itself, possibly even breaking pushrods in the process!

* Brake or reverse lights being illuminated when they should not be

* Doors not unlocking by use of the key

* The car failing to even try to start (No starter motor noise)

* The car failing to start and run (Starter motor noise but the car does not start)

Any of these faults can be caused by the alarm control unit!

If you are suffering from any of these problems, please call 01202 488800 or email This email address is being protected from spambots. You need JavaScript enabled to view it. to arrange for diagnosis and repairs! 

Published in JMG News
Saturday, 10 January 2015 12:07

Free car collection and delivery

It is often inconvenient and a logistical nightmare getting your Porsche to a garage for servicing and repairs.

With this in mind, JMG Porsche are now trialing a new scheme where we will collect and deliver cars free of charge within a 10 mile radius of our workshop in Ferndown.

For customers working or living within 10 miles of our workshop, you have two convenient options.

  • Home or your place of business handover - We will collect the car from you at either your place of business or at your home, once it is ready you can pay your bill over the phone, and we can deliver the car back to you at the same location that we collected from.
  • Workshop handover with being driven to and collected from your home or work - Come to our workshop to drop off your car, discuss the repairs over a coffee, we will then drop you off at home or work and collect you again when your car is ready.

For customers further afield this opens up two convenient options.

  • Train Station handover - Meet us at the train station, we will bring the car to our workshops, while you catch the train home. Once the car is ready, pay your invoice over the phone, catch the train again and we will meet you at the train station ready for you to drive hom.
  • Workshop handover with you being driven to and from the station - Come to our workshop and discuss your repairs over a coffee, we will then drop you off at the train station so you can make your way home. Once your car is ready, we will again collect you from the train station so you can collect your car from the workshop.

Alternatively, you can still use the old method of getting the car to us and suffering the inconvenience of having to find friends or family to follow you over for when dropping off or collecting your car. For some people this may offer you the ultimate in convenience as you might need to leave your plans until the last moment at a time where we may not be able to collect it.

Terms and conditions.

As is usual these days, there are a few terms and conditions for our car collection and delivery service.

  • Our drivers are a limited resource and may at certain times of the year be booked up days or weeks in advance, so it may be essential to book your collection and delivery service, along with the work to be performed a couple of weeks in advance.
  • We will need to know that you require this service in advance of the day the work is to be performed, otherwise we will assume you will be dropping the car off to us.
  • At time of booking this service we will require a £30 non refundable, but transferable, deposit. Even though this service is free of charge for many, there are costs to the business associated in collection and delivery of you or your car, which in some cases may be Taxi fares, fuel or parking charges, as well as the time of the employee. Should you not notify us before the staff member has left for a drop off or collection, that you will not be there or available, this deposit will be retained to cover these costs. However, should you be able to offer us a couple of hours notice that you will not be there, we will hold the deposit for the alternative time that you request. When you come to pay your invoice, you will notice the deposit will be listed, and as long as work has been performed on your car, you will also see the deposit deducted against the invoice.
  • This service can not be used in conjunction with other promotions, such as with club discounts, free-new-customer-inspections, discount vouchers or competition prizes.
  • Collection and delivery services will usually be limited to outside of rush hour times, such as only being available between 10am and 4pm on week days. However if this is not convenient to you, please explain your situation to our service manager, who has the power to change this policy on a case by case basis.
Published in JMG News
Wednesday, 10 October 2012 00:00

JMG Porsche Bournemouth

COVID-19 Update - We are still open, but taking things seriously!

For the last couple of weeks, we have been planning and taking steps to be prepared to keep offering our customers good service and making it easy for you to use us!

  • Car collection and delivery services - We have always offered collection and delivery within certain postcodes in the local area, but that is now extended nationwide (Costs apply)
  • Fresh gloves used - whenever we deal with different customers or move between cars.
  • Your car protected while it is here - Plastic shrink wrap applied to your steering wheel, gear lever, handbrake and controls while it is in our care. Along with seat covers being used as always.
  • Payment by phone, rather than in-person - To avoid you having to use our payment machine keypad, we are emailing customers invoices once your car is ready, and then requesting you pay by card over the phone.
  • Your car externally washed - We have always washed cars before they are collected, but as now using chemicals that are both kind to your car, but aggressive towards biological entities, such as germs, bacteria and the virus.
  • Your car internally decontaminated - We have invested in a method to decontaminate the interior of your car, even deep into the vents and heater! The process is aggressive towards biological germs, bacteria and virus compounds, but kind to your interior! This is performed once we know you are here, or a quarter of an hour away, or the car is on your driveway if we are delivering it.
  • Our staff monitored and protected - We are keeping an eye on staff for signs of them having the virus, and we are taking a common-sense approach to all of our activities. We are also constantly talking to staff about any further measures that we can implement.
  • Everything under daily review - We are monitoring the advice of the government on a daily basis, and constantly reviewing our policies. But two things will remain our priority, you, our customers' health as well as that of our staff.

Family-run Independent Porsche Specialists 

Modern Classics through to the very latest models.

  • Fully equipped workshops with everything you would expect to find at a main dealership and more.
  • Comfortable new customer waiting area where you can enjoy free wifi and refreshments while your Porsche is being pampered.
  • Free collection and delivery of your Porsche within 7 miles of Bournemouth (Covering Poole, Christchurch, Ferndown, Ringwood etc)
  • Free loan car while yours is being serviced or repaired.
  • Recovery service available nationwide.
  • The only Porsche specialist we know of built of three generations of a family business, stretching back to the early 1970s
  • Porsche only technicians, we do not work on any other marque.
  • Porsche servicing, diagnosis, repair and modification, all under one roof.
  • Our senior technician and owner is the one and only Jon Mitchell, who has alone built up a reputation over 30 years experience, is the technical advisor for Porsche Club GB, The Independent Porsche Enthusiasts Club, as well as being a published author of Porsche books.
  • Lifts available to Bournemouth, Poole and Christchurch train stations.
  • With customers all over the UK and channel islands, we also have customers who ship their cars to us from Belgium, France, Germany, Greece, Spain, Turkey, Switzerland, the Netherlands, Hong Kong, Singapore, Canada and the USA. 

Call us to discuss your requirements on 01202 488800








Published in Frontpage Content
Saturday, 02 June 2012 11:09

Diagnosis - Emissions

Following on from our other diagnosis articles, in this article Jon Mitchell is going to talk a little about exhaust emissions.

As we go crawling inside the exhaust of a Porsche, we will take a look at the exhaust emissions, what each of the gasses are, what effect they have on your engine and how they effect the environment.

Exhaust Emissions.

The normal air that we breathe is 80% Nitrogen and 20% Oxygen, with a varied trace of other gasses.

Petrol is a hydrocarbon fuel, comprised of a mixture of carbons and hydrogen. If our engines were 100% efficient, burning all the fuel completely, the oxygen would combine with carbon to form carbon dioxide (C02) and with hydrogen to form water (H2O). The perfect engine therefore would inhale a perfect mixture of air and fuel and exhaust carbon dioxide and water. For every gallon of fuel burnt, a gallon of water would be produced and once the engine was warmed up, the water would exhaust as steam.

Unfortunately a perfect engine does not yet exist and combustion is always to an extent incomplete, in reality the engine in your Porsche will consume close to ideal ratios of fuel and air but will exhaust various compounds including hydrocarbons, carbon dioxide, carbon monoxide, oxides of nitrogen, water vapor and even oxygen.

Most of these gasses are relatively harmless in the quantities that are exhausted by a single Porsche in an open space. In an enclosed space some of them become deadly. However when millions of cars around the world are exhausting these compounds the accumulated effect is harmful to the environment.

So lets take a look at some of these gasses in more detail.


Carbon Dioxide

One molecule of CO2 contains one atom of carbon and two atoms of oxygen. CO2 is chemically stable and does not easily react with other substances. It is not poisonous, it is produced by all animals that breathe, including fish. Oxygen is inhaled and Co2 exhaled at a concentration of around 5%.

CO2 is absorbed by all green plants by a process of photo-synthesis which only happens during daylight hours, which also produces and releases oxygen.

A combination of the loss of the rainforest around the world, along with the increased production of CO2 by population, cars and industry, is a concern as CO2 helps trap heat within the atmosphere.

CO2 is a byproduct caused by combusion.

Within an engine the levels of CO2 is likely to be between 13 and 15% with a correctly running engine with a correct air fuel ratio. Less than 8% would indicate an improper air fuel mixture, a missfire or leaking exhaust. Above idle speeds CO2 is likely to increase by around 2% because of the increased RPM causing higher efficiency.

Carbon Monoxide

Carbon Monoxide or CO is a very poisonous substance and accounts for around 47% of all air pollution.

CO is also an exhaust emission that is tested for during a UK MOT test. Elevated levels of CO will cause an MOT failure and the levels set by VOSA (The official body of the MOT Test) varies from car to car, dependent on the manufacture date of the car, as well as what equipment is installed.

CO can be deadly to people, if breathed for a sustained period it joins to red blood cells, blocking the path for oxygen molecules, eventually causing death.

CO within the exhaust would indicate incompletely burnt fuel. There will always be a component of CO within an exhaust

High levels of CO are normally caused by to high a fuel quantity being consumed for the amount of air combined with it. This could be caused by a blocked breather, clogged air filter, high fuel pressure a worn camshaft, faulty air flow metering or faulty exhaust gas sensing.



Petrol is an almost pure hydrocarbon, another name for hydrocarbons would be its chemical symbol which is HC.

Hydrocarbons within the exhaust indicate unburnt fuel and are measured in ppm or parts per million.

Hydrocarbons as you can imagine can be raw fuel that is atomised or vapourised, as well as being chemically altered ingredients of the original fuel. They can be extremely dangerous to the eyes, nose and lungs.

Hydrocarbons when combined with high NOx (Oxides of Nitrogen) and sunshine, cause photochemical smog to form in the upper and lower atmospheres. Not such a problem in the UK, but in California it has been a massive problem for many years.


Lead used to be used in fuels as it lubricated valves, prevented detonation.

Lead is a celular poison for blood, bone marrow and nerve cells. Lead has not been available in mainstream fuels for some time, and even when it was last available in forecourt fuels it was in minute quantities compared with the 1960's and 1970's.

All Porsche models made since the 1960's can run without lead in the fuel in standard specification. Typically cars with cast iron heads require conversion and all Porsche models have aluminium heads, which already have hard valve seats and valve guides not requiring lead in the fuel.


Oxygen, or O2 (its chemical symbol) consists of two Oxygen molecules and is measured in % of volume.

A very small percentage of O2 will be within the exhaust of a correctly fueled and performing car, as combusion will never be complete and too little oxygen would cause higher hydrocarbons or CO. Typically O2 levels will be around 1 - 2% by volume, pre catalytic converter.

If the O2 level is higher than this, typically it may mean that there is an exhaust leak or the mixture is too lean (may also have high hydrocarbons in some cases).

Oxides of Notrogen or Nitrogen Monoxide and Nitrogen Dioxide, Nitrogen Nitrate.

NOx as it is also known is formed through high pressures and high temperatures.

The N symbolises one Nitrogen atom combined with oxygen atoms (the O), the x symbolises the number of oxygen atoms combined to a nitrogen atom.

NO is Nitrogen Monoxide. Which is one Nitrogen molecule linked to one oxygen molecule. Another name for this is Nitric Oxide. It is caused by by combustion temperatures rising above 1370 degree c.

Typically Nitrogen monoxide, especially at higher engine speeds and loads, causes the production of Nitrogen Dioxide (NO2), Nitrogen Nitrate (NO3) and Ozone (O3). Nitrogen dioxide often forms a brown fog, which is the typical smog that Californians complain about.

One annoyance is that NOX emissions can be caused by high performance engines, especially at their peak efficiency with at cruising speeds with a perfect air fuel ratio (AFR). A way of reducing NOX is to recirculate a small amount of exhaust gasses into the combustion chamber, which reduces combustion temperatures and therefore NOX emissions. However, it also reduces power, so is often employed only in cruising conditions or in conditions tested by government bodies.

Solutions for the engine designer.

Now that we have dealt with the exhaust emissions exhausting directly from the engine, we can cover some ideas and methods of reducing emissions employed by modern engines.

Catalytic converters

All modern cars are fitted with a catalytic converter. Also known as a Catalyst or Cat.

Since January of 1993 all UK cars have been fitted with a catalytic converter.

The principle reason for the use of catalytic converters was to complete the combustion of the exhaust gasses so that they are less polluting to the environment.

A Catalyst is something which promotes a chemical reaction without itself being effected. On a car it works as a secondary combustion chamber to complete the combustion of anything left over after the primary combustion has taken place.

At 300 degrees C the catalytic converter begins to work, its happiest temperature is between 400 and 800 degrees, where it will be most efficient, once the catalytic converter passes 1000 degrees, some of the precious metals within the catalytic converter will begin to break down and melt.

When working in the correct temperature range, with the correct levels of exhaust gasses entering it, the catalytic converter will convert CO and HC into H2O and CO2. NOx is reduced by a process of reduction where oxygen and nitrogen are forced apart. The Oxygen combines with CO to produce CO2 and N2.

A weak mixture with a high level of O2 is good for the oxidation of CO and HC. On the other hand, a rich mixture with some CO aids the reduction of NOx. A comprimise is reached by the engine running at a mixture of 14 to 1. This means the engine is slightly richer than ideal and use more fuel, but it will reduce NOx emissions, yet will be lean enough to combine CO and HC to create H2O while also running the catalytic converter hot enough to stay within its ideal temperature band. Often with modern engine management the engine will quickly alternate between slightly rich and slightly lean to allow the catalytic process to get the best of both ideals.

H2S is a gas not tested in the UK for MOT testing, but is often released by a new catalytic converter, which causes the smell of rotten eggs that can sometimes be smelt with a new cat. However sometimes with a car running rich will also cause this smell on the overrun as it becomes lean and the catalytic converter creates this gas as a byproduct of burning off excess carbon caused by the rich state.

A car fitted with a catalytic converter has to run perfectly at all times, a misfire, sensor fault, wrong fuel pressure, or many other, can permanently damage the catalytic converter. As an expensive item it is wise to follow a specialists advice with preventative work on the engine, before it becomes a fault, but also if you experience a fault, to have it attended to immediately.


As the engine operates, air and fuel are mixed together, drawn into each cylinder. The Air Fuel Ratio (or AFR) at which air and fuel burn at their most efficient is known as the Stoichiometric point and is where HC and CO should be at their lowest and CO2 should be at its highest. This ratio is 14.7:1 by weight, and it is also called Lambda = 1 which is the greek word for "correct".

Various fractions of Lambda can can be converted into AFR by multiplying 14.7 by the fraction. The AFR/Lambda chart is the result.

Although lambda=1 is not the ideal point fuel consumption, it is the best comprimise for using a catalytic converter to oxidise CO, HC and NOx. Therefore if the Lambda can be kept between 0.98 and 1.02 the efficiency of the catalytic converter will be in excess of 90%. The reason being that the lower emissions from the engine reduce the work required for the catalytic converter to convert these harmful gasses into more acceptable ones.

Oxygen Sensor

A sensor placed within the exhaust system to sense the levels of oxygen present following combustion, the Oxygen Sensor is known by many names. Including the Oxygen Sensor, Lambda Sensor, Exhaust Gas Oxygen Sensor (EGOS) or even when used with a heating element a Heated Exhaust Gas Oxygen Sensor (HEGOS). For the purpose of this article, we will stick with calling it the Oxygen Sensor.

The sensor typically has a porous ceramic tip, this tip often contains two platinum electrodes, the outer surface electrode is exposed to exhaust gas, with the inner electrode exposed to atmospheric air. The difference in oxygen content between the two electrodes produces an electrical voltage, which is read by the engine management computer to analyse the oxygen remaining in the exhaust after combustion.

The sensor is often placed before the catalytic converter for the engine management system to evaluate and adjust the mixture being fed to the engine, however more modern cars now also have one after the catalytic converter, which allows the engine management system to know how efficiently the catalytic converter is performing.

The voltage generated by an oxygen sensor is inversely proportional to the difference in oxygen content seen in the exhaust compared to the oxygen in the ambient air around the car. The engine management system will use this signal to increase or decrease the fuel provided to the engine on a split second by second basis, in effect allowing the engine to be self tuning.

Typically voltage being seen by an engine management system would be between 0.1v (lean) and 1.0v (rich). If you were to connect a volt meter to the lambda sensor while the engine is running, you would likely see the voltage changing from above and bellow 0.55volts on a regular basis, possibly to quickly for the volt meter to be able to display, in which case an average voltage of 0.55 volts may be observed.

Analysing the quantity of oxygen remaining after combustion is an excellent indicator of how rich or lean the mixture of fuel is being supplied to the engine. In theory an engine management system could solely use an oxygen sensor to decide on the quantity of fuel to inject into the engine, keeping the exhaust gasses constantly at the correct oxygen content indicating a proper mixture, which in turn would extend the lifespan of the catalytic converter and the oxygen sensor, while also providing a reasonable fuel economy. However, a car requires different levels of fuel for different driving conditions and demans, such as accelloration or decelloration, on full throuttle or part throttle, if the mixture remained at 14.7 to 1 at all times, the car would drive very poorly. As such, engine managements tend to only take notice of the oxygen sensor when cruising at a constant or near constant speed.

More recently a new type of oxygen has been available, known as a wideband sensor, which is able to read a wider range of air fuel ratios, which an engine management system can monitor and compare with target air fuel ratios at a wide range of demands and conditions to make alterations to fueling. These are also used by enthusiasts and tuners so they can monitor their exhaust oxygen content as a warning instrument as well as a tuning device.

An oxygen sensor can however be fooled. A perfect air fuel ratio may for one reason or another not fully combust both the fuel and air mixture, the oxygen sensor will see this surplus fuel, which may be interpreted as a weak mixture, especially dangerous if using an oxygen sensor to tune a car.

Mass airflow sensor (MAF Sensor)

A mass airflow sensor (also known as a MAF sensor) is a sensor sometimes used by an engine management system to measure the mass of air being consumed by the engine at any one moment in time.

As the fuel pressure and the flow from fuel injectors is usually predictable as to how much fuel will flow through them per second, knowing the correct amount of air entering an engine can provide a good assumption of how long to pulse the injectors open for, to provide the correct air fuel ratio for any one given engine speed or loading. In systems with a MAF sensor, often an oxygen sensor is also used, especially in catalytic converter equipped vehicles to provide perfect fueling in all conditions. However a faulty MAF sensor may cause the engine management system to believe there is a fault with the oxygen sensor, or indeed the other way round.

Air flow meter - Also known as a Volumetric Air Flow Meter (VAF Sensor)

Before MAF sensors were invented, the common way to measure fuel entering a fuel injected car was by using a Volumetric Air Flow sensor. When coupled with a temperature sensor, a VAF sensor can make a good approximation of the volume and mass of air entering an engine. However, their design, owning to a spring loaded trap door connected to a sensor causes this to be a component which is not only subject to wear, but also an item which offers resistance to air entering an engine, lowering performance.

Manifold Absolute Pressure Sensor - Also known as a MAP sensor

A map sensor measures the air pressure seen at the intake manifold, as the amount of air which can pass a throttle butterfly at any opening position is fixed, the combination of MAP sensor with a throttle position sensor, can also make a good aproximation of the volume of air being consumed. When combined with a temperature sensor, like with a VAF sensor, the engine is able to calculate the mass of air being consumed and calculate the fuel required for any given demand placed on the engine.

Turbo charged vehicles sometimes are fitted with both a MAF and MAP sensor to provide increased accuracy as well as telling the engine management system how much boost is being provided by the turbo or turbos. This is sometimes essential as the requirement for fuel alters with the pressure it is being compressed to. Typically, higher intake pressures require an increase in fuel quantity to avoid damage to the engine and provide maximum efficiency.

Engine Coolant Temperature sensors

Engine coolant temperature sensors are essential to the smooth and safe running of an engine. When an engine is cold, the requirement for fuel is higher than when one is warm. In addition a catalytic converter will not work until it has reached a temperature of above 250 degrees C, which means as well as an engine management system using the engine temperature to increase or decrease fuel quantity, it will also use it to know when and when not to take notice of the oxygen sensor.

Closed Loop or Open loop.

When the conditions are right, an engine management system will begin to rely on a oxygen sensor to calculate and govern the fuel quantity provided for the engine. When this is the case the condition is known as closed loop. Typically this will be when the engine has reached opperational temperature, the throttle is neither at wide open throttle nor closed at an idle position. When these conditions are not all made, the engine management system will be known as running in open loop mode.

Engine Management System (EMS), Electronic Control Unit (ECU), Digital Motor Electronic (DME)

There are many names used for the electronics used to control and engine management system as shown in the title of this section. However for the sake of this article we have referred to the Engine Management System or EMS. However all the names mean the same thing, a sophisticated (for its day) computerised control unit which monitors several sensors, decides how much fuel to supply, when to supply an ignition source (spark) along with a few housekeeping tasks and sometimes recording faults found. One of the important jobs is to ensure the car runs efficiently and with the minimum of exhaust gas emissions.

Faulty Engine

An engine fault can cause problems with exhaust emissions. A good example would be wear causing a loss of compression, which may cause the assumptions of the engine management system to be wrong and therefore the wrong quantity of fuel provided, which can result in high levels of CO and possibly hydrocarbons. In addition, and engine which burns oil can sometimes cause a raised level of hydrocarbons, which is because like the fuel you intend to use, the engine oil is a complex carbon and fuel source, which when incompletely burnt, will cause hydrocarbons and in some cases raised CO levels depending on how well it is being combusted.

Exhaust System

A faulty exhaust system may have a leak. Often you will hear people refer to an exhaust blow, but not so many people know that this will also cause air to enter the system.

For every combustion event there will be a high pressure wave traveling along the length of the exhaust, causing some exhaust gasses to possibly escape before they have reached the tailpipe. However behind each one of these high pressure waves there will also be a lower than ambient negative pressure wave, which will suck ambient air into the exhaust.

If the exhaust leak is before the oxygen sensor, the sensor will see this additional air entering the exhaust as a lean mixture, possibly causing the engine management computer to increase the mixture provided to the engine.

If the exhaust leak is after the oxygen sensor, the sensor will be oblivious to the additional air, but any diagnostic work performed by measuring the exhaust gasses at the tailpipe will be false, in particular the oxygen level.

The MOT Test

Typically, the MOT test in the UK is interested in CO, HC and O2 levels in the exhaust system, elevated quantities of any of these, beyond pre set limits will cause a failure of the UK MOT test.

Diagnosis - Hydrocarbons.

Typically, hydrocarbons are caused by an incomplete burn of the fuel provided to the engine. Normal causes of this will be poor ignition, improperly atomized fuel, consumption of engine oil or an incorrect mixture. As such, diagnosis needs to focus on engine health, ignition, fuel system health and other exhaust gasses which are present.

With hydrocarbons many garages will try to say it is a mixture problem, however unless the mixture is extremely over lean, hydrocarbons will more often be caused by something stopping that cylinder from firing correctly, leaving fuel left over. Often a rich mixture will fire correctly, however will result in high CO levels.

So if you see normal CO levels but high hydrocarbons, then the problem is probably a ignition or engine fault.

If you see low CO levels (lower than reasonable) and high hydrocarbons, the problem is probably one of the mixtures being too lean, so look into that.

If the CO levels are very high and you also have elevated hydrocarbons, the problem may well be the high mixture levels (too rich)

Overall, Hydrocarbons are one of the most important exhaust emissions to help point at the cause of an issue, if the hydrocarbons are low, it normally indicates a good ignition system as well as a fit engine.

Diagnosis - Carbon monoxide

Carbon monoxide levels are usually caused by a rich fuel mixture, which can be caused by faulty air measurement, high fuel pressure or bad exhaust oxygen sensing. However it sometimes can be a result of poor air filter condition or on older cars of a need to adjust a carburetor.

Carbon monoxide is nearly always caused by too much fuel being consumed by the engine, which can be caused by a fault in the electronic engine management system, or with the carburettor on a older engine.

It can also be caused by a faulty injector, fuel pressure regulator or o2 (lambda) sensor.

High carbon monoxide or dioxide can be a killer, so while trying to diagnose these faults, it is really important to do so in a well ventilated area, as these gasses can be a silent killer with no odor or other side effects other than a headache and death!!

Carbon monoxide levels can also be high if the engine is cold, so make sure your engine is fully warmed up before you pay too much attention to the levels, and remember that it takes twice as long for the engine to be completely warmed up than it takes for the coolant to be up to temperature. This is because water absorbs heat much faster than aluminium, iron, steel or engine oil... so be patient.

Diagnosis - Oxygen

High levels of oxygen within the exhaust system can be an indication of poor exhaust sealing. But it can also be a sign of poor combustion, depending on what other exhaust gasses are present, it can indicate poor ignition, fuel system health or engine health.

It is also worth bearing in mind that if your exhaust system is not in good condition, air can be drawn into holes in an exhaust, just as much as a poor exhaust can blow its exhaust gasses out of gaps (a surprise to most people) which can cause elevated o2 levels in the exhaust gas.

The other problem with high o2 levels is that they can cause the o2 (lambda) sensor to see this air as a weak mixture, which in turn can cause the engine management system to add lots of excessive fuel to be added, which will show up as high carbon monoxide readings and possibly even high hydrocarbon levels. This means that if one of your emissions which seem high is the o2 level, please check the condition of your exhaust system and make sure that except for the tailpipe it is extremely air tight.

Good garages like JMG Porsche will use a smoke tester to test to see if the exhaust system is airtight (where it should be) as well as using diagnostic skill to find the cause of the high o2 levels and knowing what other elements may effect them.

Diagnosis - Drivability

Often a fault can manifest itself as poor drivability of the car. In these cases, exhaust gas analysis can assist in tracking down the fault.

Symptms and causes.

An important note to make before closing this article, is that there is a very large difference between symptoms and causes.

A good example might be an engine driving poorly, the exhaust emissions for carbon monoxide may be high and the engine management system may indicate that it believes the oxygen sensor is at fault. However both these items would be symptoms, even if when tested the oxygen sensor is found to be faulty. The actual cause may be something else, such as a mass airflow sensor providing a false reading of more air entering the engine than is actually happening. In this case the cause may have actually caused the oxygen sensor to become faulty, which will result in more than one faulty component, two in this case, one being a symptom, the other being the cause.

With this in mind, it is important to never assume the cause of a fault has been found, otherwise, as with the above example, the same fault will re-occur with a new component becoming faulty again. In all cases, even if a test shows a part to be faulty, further tests should be made to other components to be sure there are not other symtoms, faulty components and indeed one or more faulty components which are actually causes of the other symptoms.

It is therefore often important to allow your technician to perform multiple tests before and after a repair is made, it is often not the technician performing needless tests, but in fact ensuring that both the symptom and the causes have been eliminated, otherwise an expensive component may need to be changed more than once!


Wednesday, 30 May 2012 21:14

The Dent Finder

Finding dents is often easy as the dent is obvious.  However some minor dents are the kind of thing you only find when washing or waxing your pride and joy.

When buying your next Porsche, being able to find dents is often a good way to help negotiate a good price, but also helps you avoid buying a car which may have hundreds of tiny dents.

At JMG Porsche our detailing toolbox has for a long time included "The Dent Board": a simple printable document with parallel lines marked at variously spaced distances and thicknesses.  The board is the result of time and effort taken to find the correct patterns and spacing, thus when used correctly, will enbable you to find dents that would be difficult to find with the naked eye.  JMG Porsche have released this tool to Porsche buyers everywhere to help them find dents and even paint texture issues with ease.

So how does it work?

When looking into the paint of a car you will see reflections - often your brain will switch off noticing these reflections in day to day life.  You can, however, use these reflections to find irregularities in the paint or panel shape.

Unfortunately, usually the reflections are random and mask dents and paint defects.  However, with "The Dent Board" you can find them with ease because now the reflection is regular, straight and highly contrasting.

Simply download the pdf file at the bottom of this page called "The Dent Finder".  Print out this document and put it onto a clipboard or some stiff cardboard, we tend to laminate them as well because we use them everyday.

Then, whenever you are inspecting paint for texture issues such as orange peel or checking panels for dents, hold the dent board against the panel in a position so you can easily see its reflection and move over the panel keeping an eye on the reflection as you do so.

Even minor dents, orange peel textures or other undesirable blemishes on your Porsche bodywork will become instantly visible.

Variations of "The Dent Finder" are used by car detailers, paint specialists and bodyshops around the world.  Now you can also use our dent board or dent finder for free!

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