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'02 BAM - Stubborn misfire in Cylinder 1 - Help?!

Discussion in 'A3/S3 Forum (8L Chassis)' started by Shinkansen, Apr 19, 2014.

  1. Shinkansen
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    Shinkansen New Member

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    Hello all,

    Long time reader/lurker posting my first issue about this great car (2002 8L BAM S3). Usually we can tackle everything ourselves but this problem has stumped us. I have searched this forum for similar issues and spent hours reading for solutions, but to no avail. Any advice would be greatly appreciated!

    So, on the way home the other night a burning smell was noticeable in the cabin at the same time as I noticed a massive drop in power and a flashing Engine Management Light. Fortunately this was literally 2 minutes from home. The car was now noticeably lumpy in its idle and rough as houses on the road.

    Ran VAG COM and lo' and behold it was detecting a misfire in cylinder 1.

    Ran to my nearest TPS and grabbed a new coil pack and spark plug. Changed the spark plug and it "appeared" to fix the issue but within 2 minutes of reversing off the driveway and driving on the road, the Engine Management light was back and so was the sub-par performance. The old spark plug was covered in black **** and if anything, changing the spark plug for a new one burned off all of the remaining deposits as the neighbours may have thought I was sending smoke signals. The white smoke stopped after a minute or two.

    After the spark plug change failed, we changed the coil pack for a new one. No difference at all. It transpires after checking with a multimeter that the old coil pack works fine.

    Now after some reading, the next culprit could be the fuel injectors. We switched cylinder 1 and 2's injector but after another VAG COM scan, the misfire remained in cylinder 1!

    We have checked the wiring and there appears to be no degradation at all.

    Before I pass this over to my friendly local mechanic, is there anything else I could try, or that could be causing this problem? I have to say, driving a limp S3 that rivals my Mrs' Aygo for acceleration, is severely depressing... especially when I assumed an "easy fix" would most likely be the issue.

    Thanks for your time ladies and gents!!

    SHiNK
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  2. Scullies
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    Scullies Active Member

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    Have you checked the coilpack harness wiring loom. Common for the wires to get brittle and fall apart.
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  3. Shinkansen
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    Shinkansen New Member

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    Did that today. Stripped back the coilpack harness wiring. There were a few cracks in wires in places, which were fixed but I couldn't see anything severe enough to cause the misfiring in cylinder one. Checked continuity and earth on all four plugs and it appears to be in fully functional working order.

    What else should I be checking now before I just turn it over to the garage?

    Bizarre.
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  4. s3ajy
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    s3ajy Member

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    Are you always getting a code come up on Vag-com for cyl1? getting the flashing eml light?
    only reason im asking i had "similar" issues but i was getting misfiring under load but no codes or eml lights were registering on vag-com or the car.
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  5. Shinkansen
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    Shinkansen New Member

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    Yup. Cylinder 1 only error code in VAGCOM and the flashing Check Engine Light!

    We changed the other three spark plugs for NGK's whilst all were accessible. We traced the loom all the way back to the ECU and tested for continuity from there. Absolutely perfect working order.

    Still none the wiser! Starting to think the worst now.
    #5
  6. s3_trev
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    s3_trev Member

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    Is there a DV or cam follower on these engines?
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  7. dave_beastttt
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    dave_beastttt New Member

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    Do a compression test.
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  8. Shinkansen
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    Shinkansen New Member

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    Thought I would update for anyone else that has this issue.

    When we were checking and stripping the coilpack harness loom we decided to change the other spark plugs as they were still rubbish Densos in cylinders 2, 3 and 4. Also a lot more easily accessible.

    Gave in and took the thing to my local friendly mechanic.
    A phone call a matter of hours later to say it was running beautifully. What did they do? Change all the spark plugs!! I have absolutely no idea why this worked, as we did exactly that. I can only imagine the deposits from not firing all the time for god knows how long conked the new one we changed. It did "feel" like it was back to normal for literally a minute before I could floor it on the motorway, before the check engine light reappeared. Didn't think to change it again.

    So, easy fix people. Worth checking the spark plugs more than once. Cheap fix. Thanks for the replies and advice. Will keep an eye on this as it could be a symptom of something more sinister.

    SHiNK
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  9. Shinkansen
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    Shinkansen New Member

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    An Update

    For anyone else having these issues/symptoms, my 8L BAM S3 was finally diagnosed as having a faulty inlet breather valve. This was creating lots of problems; causing the turbo to work too hard, increasing the pressure in the crank case and was ultimately causing oil to blow into the engine. This was causing the damp spark plugs (causing the misfire) and also the white smoke from the exhaust (which we assumed at first was the **** being cleared out from misfiring for a period of time).

    Cheap easy fix (£10 for a valve) and 1hr labour at your local friendly independent garage, or if you have the time and equipment, yourself!

    Hope someone finds this useful!

    SHiNK
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  10. badger5
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    badger5 RIP S3dave Site Sponsor

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    thanks for sharing

    great closure
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  11. kwistof
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    kwistof South East Events Moderator Regional Rep

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    Glad to hear it was a cheap fix in the end- even though there was quiet a bit of time off the road factored in
    #11
  12. friggens
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    friggens New Member

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    Hi
    Iv just read up on this forum. Im having the same issues with mine started misfiring but on cylinder 2 changed the coil pack and all 4 plugs and nothing changed. But started too smoke clouds of white smoke from the exhaust. Im gunna go with ur advice and change the plugs again fingers crossed my s3 will be bk too normal
    Cheers
    #12

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