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This thread has been created to enable you to post about the issues you've been having with your Cooper S along with any pictures/evidence to show a carbon build up problem. The end goal is for members to be able to refer MINI Customer Services to this thread to show that this is a real issue on the Cooper S so please follow a few short guidelines before posting:


  • Only post up your findings in ONE POST and come back and edit that post with future evidence rather than starting a new post
  • Please use the new post template below to ensure you add the basic information required before going into detail
  • Do not use this thread to comment on other peoples issues, only post your first hand experience, use the discussion thread here for all other comments: http://www.minitorque.com/forum/f15...uild-up-discuss-issues-here-32764/#post568544
  • Go into detail - post up as much evidence as you can re the issues you are having, where possible include pictures and statements from any dealer or independent MINI specialist you are dealing with.
  • Encourage others to post their findings here - doesn't matter what forum they post on, the more information we get in one place the better chance we have of MINI admitting there is a problem and either resolving it under warranty, or at least offering a sizable goodwill payment towards its resolution. So please refer any other discussion going on around the world to this thread
  • Once your MINI has been 'de-coked' please update your post so people can understand how you went about it. Also include what steps you have taken to stop this happening again i.e catch cans, water-methanol injection etc
  • If you have any information that you think could benefit this first post then please PM me directly and I will ensure it is updated if relevant

First off, what is carbon build up and how does it affect your engine?

As the engine operates, carbon deposits may form in places such as the valves, ports, pistons, head gasket and piston rings. This carbon can interfere with normal combustion is several ways. It can alter the engines operating temperature, compression ratio, and several other important factors involved with combustion and sensor readings.

How can carbon alter the sensor readings?

The carbon contributes to abnormal combustion in several ways, but the most dramatic effect in a modern fuel injected engine is the "sponge effect". As the fuel mixture in the cylinder is compressed, the carbon has a tendency to absorb both oxygen and fuel. Once the ignition spark fires, the flame front normally spreads through the chamber, consuming the fuel and air, however, the carbon has a tendency to extinguish the flame front and stifle combustion.

This, combined with the fuel and air that was absorbed, results in poor efficiency. As the chamber decompresses during the exhaust portion of the stroke, the unburned fuel and air is released, resulting in both excessive fuel and air (containing oxygen) entering the exhaust system. The O2 sensor detects the excessive oxygen and the vehicle computer (ECM, ECU, PCM) compensates for this by enriching the mixture.

This causes poor catalyst efficiency, and increased carbon formation. The situation is aggravated by the overly rich mixture, resulting in the engine's failure to reach a sufficient temperature to remove these deposits. In addition, the excess fuel can permanently damage the catalyst or cause meltdown (on the outlet side as opposed to the inlet) and can get hot enough to melt stainless steel substrates.

Does carbon alter combustion in other ways?

Absolutely, in addition to causing poor combustion, excessive build up can also alter the vehicle's compression ratio. The carbon fills up spaces around the piston rings, head gasket, and spark plugs. This decreases the amount of space that is available in the combustion chamber. This increases the compression, which can cause the engine to overheat, ping (detonate), and also causes an increase in NOX emissions. Due to the fact that the carbon can retain oxygen from the combustion process, it can cause another interesting effect that can cause the vehicle to either trigger a light or fail an emissions test.

A catalytic converter requires certain conditions to break down harmful emissions. It requires a slightly rich mixture and a low oxygen level in the exhaust system to break down NOX. Because the carbon causes increased NOX emissions and also causes excessive oxygen to leave the combustion chamber unconsumed, this actually impairs the catalyst's ability to remove the NOX from the exhaust.

What does carbon build up look like on the MINI?







What are the symptoms that have been reported re carbon build up on the MINI?

Rough idle on cold starts
Check engine light illuminated
Drop in performance

(More to be added in due course)

New Post Template


MINI Model:
Model Year:
Full MINI Service History? (include type/dates/mileage these were carried out):
MINI Specialist Service History? (include type/dates/mileage these were carried out)
List Aftermarket Modifications:
Fuel Used: (include RON rating)
Driving Style: (commuter, weekends only, track days?):
Engine Codes Thrown:
 

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MINI Model: Cooper S
Model Year: 2007 - N14 engine
Current Mileage: 59,200
Full MINI Service History? : Yes. Specifics TBC
List Aftermarket Modifications: None
Fuel Used: V Power 90% time with Momentum 10%
Driving Style: Commuter and Weekend car
Engine Codes Thrown: TBC
 

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MINI Model: Cooper S
Model Year: 2006 - N14 engine
Current Mileage: 31,982 Full MINI Service History? : Yes, plus 6month oil changes from 20,000 miles last 3 years plus
List Aftermarket Modifications: Too ManyFuel Used: V Power 95% time with Momentum 5%
Driving Style: Weekend car
Engine Codes Thrown: Not related to coking but lots of others (It's a R56 thing)

Just some info, took head off car following timming chain going so took some pictures of inlet ports/Valves

Some history of car
November Built 2006 registered DEC 2006
Brought from delear with 15,200 miles no service at this point from TLC pack 1 year old
First service at 20,000 miles from BMW 2008
Next service from BMW DEC 2009 (Inspection 2)
Serviced every 6 months (Min engine flush and oil service) after DEC 2009 too present day
Oil catch can fitted 2011 and rear pcv blocked off early 2012 to present day, seafoam treatment every 6months from mid 2011

Now on inspection these are no way the worse i have seen and i have had no issue's with engine power delivery, but as you can see the build up is still there so those who have had the head off and cleaned or walnut cleaned fit those OCC straight away and tell BMW fuck off about warranty issue's for fitting OCC's.
Cylinder 1
Nose Tooth Mouth Organ Jaw

Cylinder 2
Tooth Water Macro photography Jaw Close-up

Cylinder 3
Sky Mouth Cloud Photography Macro photography

Cylinder 4
Tooth Nose Mouth Skin Jaw

Sorry about poor photos when i get the valves out will take more photo,s, hope this helps to us coke sufering people i may start a self help group so i can blame my parents...:laugh:
 

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356 Posts
MINI Model: Cooper S w/Stage 1 tuning kit
Model Year: 11/2008
Full MINI Service History? (include type/dates/mileage these were carried out): Don't know type but done Jan 2010 (oil change) 18k, Dec 11 27k MINI service
MINI Specialist Service History?
List Aftermarket Modifications: No engine mods at the time
Fuel Used: (include RON rating) Momentum/ V-power every second fill. Normal Shell otherwise
Driving Style: (commuter, weekends only, track days?): Commuter with weekend motorway miles
Engine Codes Thrown: No idea

Extras: Car was OK with no significant problems then it started using 1litre oil every 1k miles (never used a drop before).
I threw some BG44 through it then the problems really started. Misfire on acceleration. Still under warranty, went in and coke was established. On strip down the bores were badly scored so they put a new bottom end in and decoked the rest at 38k. Oil catch can now fitted, not using any oil and now at 51k miles.
 

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228 Posts
MINI Model: COOPER S
Model Year: 2007
Full MINI Service History? (include type/dates/mileage these were carried out): FSH in accordance with BMW spec. 80,000 approx at the time of fault in Jan 2012
List Aftermarket Modifications: Panel filter only
Fuel Used: (include RON rating): Mostly 95 RON, mostly non-supermaket.
Driving Style: (commuter, weekends only, track days?): Commute and weekend car.
Engine Codes Thrown: Faults on cyclinders 2 and 4

Had rough idling and EML light illuminated. Was taken to the dealer where they diagnosed a faulty HPFP and coked engine. Full cost to replace both £1800. I took issue with this and got a goodwill gesture from MINI of £900 from the cost of a decoke, nothing towards the HPFP. Was informed by the dealers (Lloyd Newcastle) that the inlet manifold was so bad it had to be replaced.

Fitted with OCC onto side PCV on receipt back with rear facing PCV blocked off. Currently (April 2013) suffering high oil consumption presumably due to rear PCV being blocked. Current miles 105k
 

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MINI Model: Cooper S with Stage 1 JCW conversion
Model Year: 2006
Full MINI Service History? (include type/dates/mileage these were carried out): FSH (will update) Cherished car
MINI Specialist Service History? (include type/dates/mileage these were carried out): N/A
List Aftermarket Modifications: None
Fuel Used: V Power (what ever ron that is..?)
Driving Style (commuter, weekends only, track days?): Short Journeys to and from work, occasional long runs on weekends, always warmed up and down
Engine Codes Thrown: Lower Lambda probe faulty

Had the car a year, had a timing chain fix done around 18k i purchased it on 32k. mechanicly in the year ive had it it has had another timing kit fitted, a lambda probe, alternator belt and a de coke. only fault its thrown up was the cel light for the lambda probe... will update service history when i get time.
 

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MINI Model: mini clubman cooper s
Model Year: 2008
Full MINI Service History? (include type/dates/mileage these were carried out): full dealer to date
MINI Specialist Service History? (include type/dates/mileage these were carried out)
List Aftermarket Modifications: forge fmic, alta stiffy spring, piercross panel filter,evolve decat downpipe,forge resonator delete and p-torque remap
Fuel Used: (include RON rating)tesco 99
Driving Style: (commuter, weekends only, track days?): commuter
Engine Codes Thrown lambda probe (but maybe down to decat)

has anyone tried sea foam to help this?? thinking of trying it after watching a few clips on you tube of peoples results.
 

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548 Posts
MINI Model: MINI Cooper s
Model Year: 2008
Full MINI Service History? (include type/dates/mileage these were carried out): Full MINI service history
MINI Specialist Service History? (include type/dates/mileage these were carried out): N/A
List Aftermarket Modifications: None
Fuel Used: (include RON rating): Mostly 95 RON.
Driving Style: (commuter, weekends only, track days?): commuter, weekends
Engine Codes Thrown: None to date
 

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Car bought October 2013 / 2 previous owners / 62000 miles

MINI Model: Mini Cooper S
Model Year: 2007
Full MINI Service History? Full Mini Service History
MINI Specialist Service History? NA
List Aftermarket Modifications: NONE
Fuel Used: (include RON rating) (By us uptill now normal Unleaded. Super will be used from now on)
Driving Style: (commuter, weekends only, track days?): Commuter / Short distances 4 mile each way and normal driving
Engine Codes Thrown: None

When we bought the car in October 2013 for my wife i drove the car home and gave it a bit of wellie and instantly had the engine management light come on. On inspection and diagnostic it showed coil no3 had gone down and we replaced it and had the codes reset / engine management reset.

From what we know the car had a woman owner first followed by a gentleman who owned it for 3 years and did mainly motorway mileage.

After having coil replaced all seemed well until every time i would put the car into sport mode and "Boot" it ... it seemed to cough and splutter a lot under "Hard" acceleration ?

In "Normal" mode it did'nt seem quite as bad but still under heavy acceleration occasionally seemed to mis-fire or cough and splutter.

After quite a bit of research i stumbled upon this de-coke thread and started looking for a Mini - Specialist to take the car to for further investigation.

I knew from other threads that it would not be worth approaching BMW as the car was too old.

Again after much searching i found a thread i think on piston-heads where someone with a similar problem recommended a Mini specialist who was not too far away from me in Surrey.
I rang TWG Automotive and spoke to Will who could not have been more helpful and had a good idea of what the problem was. He said that he was 99.9% certain it would need a de-coke as the "Inlet Valves + Ports" would be blocked. Apparently when this happens the ECU will struggle to give the correct fuel / air mixture as the diameter of the inler ports has changed thus changing the fuel air mixture.

I booked the car in and we took it over to "Will" who did a De-Coke with the BWM "Walnut" machine and replaced all four plugs. Total cost £257.00 and this has "Completely" Cured the Car :)

Can't recommend "Will" at TWG Automotive highly enough.

Surrey's independent BMW and MINI specialist | TWG Automotive

Absolutely first class service and the car is now driving like a "Dream". Revs so cleanly through the rev range i might have to buy one meself :)

Regards

Paul
 

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Can't recommend "Will" at TWG Automotive highly enough.

Surrey's independent BMW and MINI specialist | TWG Automotive

Absolutely first class service and the car is now driving like a "Dream". Revs so cleanly through the rev range i might have to buy one meself :)

Regards

Paul
Booking mine in here too on 19th April.

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Car bought April 2013 / 3 previous owners / 60000 miles

MINI Model: Clubman Cooper S
Model Year: 2009
Full MINI Service History? Full Mini Service History
MINI Specialist Service History? NA
List Aftermarket Modifications: NONE
Fuel Used: (include RON rating) - April 2013 onwards - BP Ultimate 97 or Texaco 97
Driving Style: (commuter, weekends only, track days?): Commuter + Weekend driver
Engine Codes Thrown: None

Car splutters under normal acceleration on higher gears, and at low gears it feels very uneasy. As mentioned above, having a decoke done (hopefully) at a great price of £180 all in once finished. Got to drive 1hr 40 for the work, but beats paying Stealer prices.
 

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Carbon build up issues are no more with the aid of a very simple service with hydrogen technology.
I had mine done, it took 30 mins and she ran like a dream.
Cost £70.00 to remove the carbon build up and left my car with a great increase in performance, power and fuel efficiency.
It ran quieter and smoother.
It cleans the carbon from the air intake right through to the exhaust including turbo's, valves, combustion chamber, inlet manifold etc,DPF(if not too far gone), EGR and CATs...
Very effective, cheap and non invasive service.
 

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Carbon build up issues are no more with the aid of a very simple service with hydrogen technology.
I had mine done, it took 30 mins and she ran like a dream.
Cost £70.00 to remove the carbon build up and left my car with a great increase in performance, power and fuel efficiency.
It ran quieter and smoother.
It cleans the carbon from the air intake right through to the exhaust including turbo's, valves, combustion chamber, inlet manifold etc,DPF(if not too far gone), EGR and CATs...
Very effective, cheap and non invasive service.
Great first post, care to elaborate on where and who and what this actual miracle cure is?
 

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Great first post, care to elaborate on where and who and what this actual miracle cure is?
Thanks.
You can now get this service at many garages across the UK and some are going mobile with the service.
I'll PM you who.
There's no miracle just science.
The machine makes pure hydrogen which is fed into the air intake, it provides a more complete burn in the combustion chamber and elsewhere draws the carbon to it, a bit like cars are now painted on the production line with positive and negative charging etc. etc.
The process is proven and the results are immediate.
 
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