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Huge missfire under boost

Discussion in 'A3/S3 Forum (8L Chassis)' started by S3-Andy, Sep 10, 2008.

  1. S3-Andy
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    S3-Andy Member

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    [Sep 10, 2008]
    well guys as the title says my s3 has developed a huge missfire,
    the car drove fine to work this morning,no problems at all,however this evening on the way home as i entered a dual cariage way i put my foot down for a bit of go, it reved to about 2500 revs just as it was coming on boost i got a huge missfire/splutter,changed up and got the same in all gears all between 2-3000 revs.
    Going to have a proper look tommorow after work,i am going to start with plugs and coils as i have spares,i had a quick listen and can hear any boost leaks,
    the car revs and runs fine when parked up its only happening under boost, if it was a coil would the car no run lumpy?
    there is no management light, anyone experienced a similar problem or have any advice?
    would the maf or injector or any fuel issue bring the management light on?
    the car is a 2001 and has a revo map
    cheers for any help
    andy
    #1
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  3. Tastyterrier
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    Tastyterrier Monkey Trainer

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    [Sep 10, 2008]
    Could well be the MAF, try running for a short while (like a mile or so) with it unplugged.
    #2
  4. themanthatcan
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    themanthatcan Member VCDS Map User

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    [Sep 10, 2008]
    Sounds like a dying coil pack to me. Does the car drive ok if you stay off boost?
    #3
  5. DBXdarkangel
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    DBXdarkangel Member

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    [Sep 10, 2008]
    mine did the exact same thing. turns out it was the hose that goes from the turbo to the intercooler (near the front drivers inner wheel arch) i tightened it up and all was well. soon as hit 3k revs when the turbo kicked in, the pressure was lost and the car felt like i was breaking and miss fired real bad.

    http://www.audi-sport.net/vb/showthread.php?t=58464&highlight=turbo
    #4
  6. S3-Andy
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    S3-Andy Member

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    [Sep 10, 2008]
    ill give all hoses a proper check tomorrow and yes the car seems fine when not on boost which does give the impression it could be boost related or prehaps the coils are just made to work harder when on boost?
    #5
  7. DBXdarkangel
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    DBXdarkangel Member

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    [Sep 10, 2008]
    took me hours to check all hoses on mine properly. id check teh intercooler one i mentioned first. might save ya time m8ty. because the juberlee clip was near the wheel arch. it started rusting and for some reason worked loose with the water.
    #6
  8. [Dave B]
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    [Dave B] Rrrrrrrr-tech

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    [Sep 10, 2008]
    I reckon it's a coil pack, the symptoms are the same as when two of mine went pop.
    #7
  9. S3-Andy
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    S3-Andy Member

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    [Sep 10, 2008]
    i think thats gonna be first on the list
    got a spare new set when i bought the car
    cheers
    #8
  10. fran-s3
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    fran-s3 Active Member VCDS Map User

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    [Sep 11, 2008]
    Just to throw another cat in the pigeons, my did exactly the same thing.. I had multiple missfires come up on boost and my exhaust was even popping. Turned out it was my fuel pump! Obv wasn't getting enough fuel when it really needed it most... But yeah VAG-COM will be a big help, get someone to log your run.
    #9
  11. tel
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    tel 4x4 junkie

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    [Sep 11, 2008]
    mine was doing this after my remap it was my plugs at fault
    #10
  12. S3-Andy
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    S3-Andy Member

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    [Sep 11, 2008]
    just thought i would give a quick up date,
    drove the car to work this morning and found it still mis behaving in the same way although if you eased on the power gently it seemed fine,anyway i changed the 4 coil packs during my 30 min dinner break and glad to say it is a 100% improvement,only drove a few mile home but seemed to be responding and picking up very well,so it looks like problem solved,thanks to every one for their input :thumbsup:
    the car has only done 43k but has a revo map is this a common fault should i expect to replace them anytime again?
    just glad the previous owner gave me a new set when i purchased the car 6 month ago
    thanks again
    #11
  13. [Dave B]
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    [Dave B] Rrrrrrrr-tech

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    [Sep 11, 2008]
    I remapped mine at 42k and it nobled the plugs with a month, that was 18 months ago now and it's been fine since. Which revision coilpack did you replace the knackered ones with? If it was the latest one (they have a letter at the end of the part code, I think the latest is J or R but can't remember exactly) then you should be fine.
    #12
  14. S3-Andy
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    S3-Andy Member

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    [Sep 11, 2008]
    it had new plugs less than 3k ago,
    not sure about the code could be L i think, dont know when they were bought but at least i never had to shell out for them so i cant complain.
    #13
  15. Jimmeh
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    Jimmeh Active Member

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    [Sep 14, 2008]
    Can someone link to me to some plugs I can try in my S3? Garage did some pressure tests and fuel pump etc is still fine.. Wouldn't mind try to change the coilpacks myself to see if I can save a trip to JBS in Chesterfield.

    Is it any easy fix?
    #14
  16. Tastyterrier
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    Tastyterrier Monkey Trainer

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    [Sep 14, 2008]
    I have Bosch Super 4s in mine, they seem to work really well with the remap.

    Changing them is a sinch. Remove engine cover, pull the coil packs vertically upwards, take the spark plugs out of the cylinder head with a torque wrench with an extension arm and Spark Plug adaptor, refit new plugs (careful not to cross the thread), torque up the setting quoted on the plug and push the new coil pack down onto the spark plug until it clicks (should only need medium force).:thumbsup:
    #15
  17. tel
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    tel 4x4 junkie

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    [Sep 17, 2008]
    after loads of looking i went for bkr7e with a .28 gap which is a stage cooler
    they say every 50bhp over standard you go you need 1 stage cooler plug

    they sorted my running out and gave me better mileage

    super 4s were the plugs i had fitted that were giving me all my problems
    #16
  18. 1animal1
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    1animal1 The Clar!! it mouves!!! VCDS Map User

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    [Sep 17, 2008]
    so what are we concluding here, that Audi plugs will do the trick when remapped?
    #17
  19. Jimmeh
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    Jimmeh Active Member

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    [Sep 17, 2008]
    I'm yet to get my car back from the spray shop, but can someone send me a link to some plugs!? The plugs that tel talks about if poss... I want to try as much as I can at home, before sendind the car in to a 'local' specialist.. (£££!)

    would it be worth me letting Audi takeWmy car from the Sprayshop to do a VAGCOM run on it? Any idea how much they'd charge? (I'd like to find someone off here local too me if preferable, pay them rather than Audi - Newark, Nottinghamshire)
    #18
  20. lee16037
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    lee16037 New Member

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    [Aug 7, 2009]
    hi my a3 2.0 tdi is doin this was fine yesterday then put sum deisel in and it started splutterin between 2 & 3 thou revs dont now if the fuel has got sum **** init or summat anyone any ideas ??? thanks
    #19
  21. s3 Hoggy
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    s3 Hoggy Whats going on???

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    [Aug 7, 2009]
    Hi lee you might get a better responce if you post in the 8p or diesel section mate
    #20
  22. lee16037
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    lee16037 New Member

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    [Aug 7, 2009]
    cheers hoggy can u tell me ow 2 do this i i only joined 2day and cant find where 2 go :thumbsup:
    #21
  23. s3 Hoggy
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    s3 Hoggy Whats going on???

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    [Aug 7, 2009]
    Yes mate if you click home in the top left corner. You will then be at the main home screen where you will find forums for; diesels, and a forum for new a3's then just hit new thread and ur away!
    #22
  24. badger5
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    badger5 www.badger5.co.uk Site Sponsor

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    [Aug 8, 2009]
    yes, there are higher cylinder pressures when under boost and a weak spark will literally blow out. wider gaps on worn plugs also will exasserbate the work the coil energy which needs to be produced to arc, and weak ones will do this.
    best to swap all 4 as they need to be matched and fresh in energy terms.. you would be surprised how much a difference to burn effeciency some weak coils will cause.
    surprised me on matts a3 BT build.. completely changed the afr it was running from ok to lean as when swapped to 4 new coils and plugs.
    regards
    bill
    #23
  25. Fuzzy felt
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    Fuzzy felt Member

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    [Aug 8, 2009]
    i am suffering exactly the same problem at the moment, just had a remap and the car is now misfiring badly, the chap said it is almost certainly the coil packs, does anyone know the best place to get them, or is it a main dealer visit ? also, does anyone know how much they are at audi?
    #24
  26. badger5
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    badger5 www.badger5.co.uk Site Sponsor

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    [Aug 9, 2009]
    £25 approx each + vat

    GSF car parts, or your local TPS
    #25
  27. Fuzzy felt
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    Fuzzy felt Member

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    [Aug 9, 2009]
    thanks Badger, who are TPS ?
    #26
  28. Andrew@A.L.D
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    Andrew@A.L.D Cylinder Head Master

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    [Aug 9, 2009]
    #27
  29. Fuzzy felt
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    Fuzzy felt Member

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    [Aug 9, 2009]
    thanks Andrew, i'll look into them
    #28
  30. IIIadidasboy
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    IIIadidasboy Member

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    [Aug 9, 2009]
    Can't belive just how many of us are suffering from misfires at the moment - must be something in the air!!!!

    I can see a swell in coil pack / MAF sales coming up!!
    #29
  31. badger5
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    badger5 www.badger5.co.uk Site Sponsor

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    [Aug 10, 2009]
    TPS = Trade Parts (aka VW/Audi group)
    #30
  32. Fuzzy felt
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    Fuzzy felt Member

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    [Aug 10, 2009]
    cheers badger !
    #31
  33. subby
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    subby Member

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    [Aug 12, 2009]
    Ive just put Denso Iridium Tough Spark Plug VK20Y in mine.

    Had it remapped today and they seem fine.
    #32
  34. badger5
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    badger5 www.badger5.co.uk Site Sponsor

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    [Aug 13, 2009]
    Denso Iridiums are not a plug I will ever use again.
    ceramics cracked on 3 out of 4 of mine, damaging pistons and turbo.
    ££ to repair for £30 of plugs.

    NGKs for me now
    #33

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