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Mini Carbon Build-up

Discussion in 'R53 Cooper S (2001-2006)' started by krazykatkb, Jan 29, 2013.

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    krazykatkb

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    Hello,
    I have a 2006 Mini Cooper S, Automatic, Super Charged (not turbo), 91,000 miles (20,000 of those are mine).
    I believe I am about to deal with a carbon build-up problem and from my online research I am finding this is seems to be a common and not cheap to fix problem.
    Wondering how others have dealt with this and what advice one might have.
    I am in the process of setting up a compression test, so i do not have that piece of evidence. Basically the check engine light keeps coming on. Code indicates a misfire. It can be reset and will come back on after a couple of weeks.
    I have been told that someone else with this same issue was quoted $3500 - $4000 by the local dealer to fix (no way). I do not know if there may have been other issues at play in this person's situation. Another local mechanic has quoted me $1200 to fix (big ouch). I keep reading on line about the cleaning with walnut shells which should run about $600 to $800 (still hurts but better). Is there any place within a reasonable distance (Atlanta - Charlotte) that offers this? Is it worth it?
    Car drives fine. I can tell nothing is wrong. Previously I have tried some Techtron additive and was told to drive it hard. I imagine people on around me think me to be the obnoxious driver, but I am driving it hard. I always use Premium gas. I have read threads on other sites which indicate this can be an every 20,000 mile issue. Is that true? Wish I had seen that in my pre-purchase research.
    As always, any advice, help is welcome!
    Thanks a bunch!
    • Member
    • Technical Service Advisor

    charlson89

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    Have you taken it to a shop yet and they told you that you need carbon blasting? I work on these cars quite often and I have never done carbon blasting on the old W engines. The carbon problem has been on the problem child N14 engine. Mainly the carbon issue is because of direct injection and turbo system causing the carbon build up and misfires. Your engine is not direct injection and really shouldn't be having carbon problems unless it has another issue causing the carbon. Direct injection engines spray fuel into the combustion chamber unlike the conventional which spray fuel on the back of the intake valve thus cleaning carbon deposits. Personally I belive you are having another issue causing the misfires. Does the misfire only happen on one cylinder or does it move around?
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    krazykatkb

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    It has been in the shop and the error code reset twice. Check engine is on for the third time. I am trying to get it back in for a compression test and to find out specifically what code it is throwing. Thanks for the great info!!! I have quite a bit to learn about this car. I am embarrassed as to how little I know.
    Another piece to the puzzle is that I have been having an issue with the ASC light coming on and staying lit. I can turn the car off and then start it again and the ASC light goes off. Seems like the check engine light is coming on when I have the ASC problem. I have found some info that they could be related, but not much. The ASC issue has been occurring ever since the dealership redid my front breaks about 6 months ago.
    Thank you very much!!!
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    charlson89

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    Do keep us informed on what you find out with the car. For your other ASC light coming on do you know what the faults are in the vehicle. MINI did have a problem with the W11 engine crank vibration dampener coming loose and causing engine damage. Usually a ASC light will come on and the engine light, I have seen this before it always shows cylinder 3 has low compression and you do a CLT (cylinder leak down test) and find it coming from the bent valves in the head. I would check the vibration damper torque this could be causing both your problems, but since this is just an online diagnosis it could be something completely different.
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    krazykatkb

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    Thanks Charlson89. You got my hopes up and then dashed them:rolleyes:
    Seriously, thanks for you info it is greatly appreciated and I am learning a lot.
    Now trying to figure out how to approach my mechanic. I posted on another Mini board and they concur about the carbon issue.
    He really seems to be a good guy. Worked for the local BMW/Mini dealership for years before he got fed up with them. Recently I had to have the thermostat replaced and he let me watch and pointed out different info about the engine. I thought that was great. I am fascinated about automotive mechanics and how things work. I so want to learn more.
    Believe I am going to park the Mini and drive the old BMW until I can get back with him.
    Other kink is that the local dealer does not seem to want to look at my car since they deduced I had taken it to this person. Long story, but basically I guess I set myself up for that one.
    Thank you very much and will do my best to add to the thread as more info is gathered.
    Take it easy!
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    krazykatkb

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    Well, was able to get the car back to the mechanic today. Misfire code it is throwing is on cylinder 1. Did a compression test C1 was 120 and C2-4 were right at 155 ea. Changed the spark plugs at the same time since they were old and had to come out anyway. (I had thought the dealership had done this as part of Inspection 2, but obviously not). He also checked the engine crank vibration dampener. He too said that this is a problem with this model car, but mine seemed to be tight and ok. He is still thinking carbon build up. I asked about the machine that cleans with the walnut shells and was told that it is not an option on this model since it is not direct injected. Seems to think the ASC light is a by-product of the misfire code being thrown.
    Now back to do I fix it or trade it. I am afraid that this car is going to be way more expensive to maintain than I can afford. BMW needs about $1,000 of work, but I am thinking it is a better investment than the Mini, even at 225,000 miles.
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    charlson89

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    The misfire on cylinder one could be multiple things. I would start with the basics, plug wire swap, coil pack swap, injector swap. If the misfire follows the component to another cylinder then you know your problem. Your compression seems to be good so that means the bottom half of the engine is ok. I would still do a compression leak down test to make sure that everything is 100% ok on all cylinders. Does the misfire occur at idle or only when driving under load? Personally I would try the easy stuff first if that doesn't fix it then consider selling it.
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    krazykatkb

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    Well, the it is hard for me to say. The car seems to run and drive fine. I cannot tell anything is wrong. The check engine light has stayed on constantly for some time. So I have nothing to go on there. Actually he had a hard time resetting it tonight. The ASC light is variable, but seems to be coming on more often. Based on how that indicator is working, I would say the misfire is happening under a load. The ASC light seems to activate when I am trying to accelerate quickly. But I feel no traction issue unless the road is wet.
    That makes sense as far as the problem following the component. I will try and look into that.
    Thanks a bunch!
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    charlson89

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    The ASC light could be related to the misfire. As you driving under load the vehicles traction control system is constantly looking at you throttle position and wheel speed if it sees a difference (by which I mean the wheel speed slow) because the loss of power from a misfire it will assume there is a fault with the system. If you can please get a list of faults from the vehicles ABS module, and engine ECU. That would help with diagnosis.
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    krazykatkb

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    That does make sense. Unfortunately I do not have access to a code reader and I do not think I can take it back to the mechanic to read. Not sure if that is something Auto Zone could do? Right now the lights are out. But I know that can change any second. Person I have been using is going to back off on doing work on his own, which means I may be out of a mechanic. I just cannot afford the dealership. I really think all they are only interested in warranty work and are pricing the rest of us out of the market. Slim pickings on Mini mechanics around here.
    Thank you for all of your help. I really appreciate it!!!! :) Just kind of in a flux. The only think I really enjoy are my cars, but that may be coming to an end for a person of low modest means. Been a very bad day.
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    steven s

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    I went to Autozone to read ABS faults. They couldn't.
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    krazykatkb

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    Thanks Steven. I kind of doubted they could get that indepth. Saves me a trip.
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    CENGEN

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    I know of a third party shop that does the walnut shell treatments all the time on MINI Coopers 2002-2006. They remove the intake manifold to gain access and I have seen plenty of before and after photos. I think they might be doing 2007 and later, but I don't know that specifically.

    FYI
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    krazykatkb

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    Thanks a bunch CENGEN!!
    I found a shop that cleaned it for $2,000 less than the dealership wanted. Still out of my budget, but did not have an option. I was running better than ever after I got it back.
    Unfortunately after this, I ended up having to sell my little MINI. Man, I loved that car. It was my dream car, but I could not afford the maintenance/repairs out of warranty and I could not afford to buy one that was in warranty. I really miss that car.:(
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    CENGEN

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    Well sorry things were so expensive. Also sorry it's really hard to figure out truth from fiction. The internet doesn't help too much there either, unless you 'crowd source' an answer - and figure out if a lot of people say something is true, then it's likely if everything is comparable and equatable to your situation... then you can trust a person you have never met !! I live in Los Angeles where people don't socialize at all with their neighbors, and yet trust a yelp review by a total stranger about how good the food is at some restaurant. To me, that's wacked!!

    I love my MCS 2006 - It has changed my life for the better.

    Best of luck in the future !

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