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Bad idle when warm 8P A3 2.0 TDI

Discussion in 'A3/S3/Sportback (8P Chassis)' started by Rigla, Aug 18, 2010.

  1. Rigla
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    Rigla S Line

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    Hi guys,

    ive had my A3 for 6 days now and its great apart from one thing...

    When the car is warm about 90c it idles really bad, sound wise i dont think it sounds worse, but feel wise...when im still or at a junction the car shakes pretty bad. I popped the bonnet whilst the car was running and noticed the engine was moving quiet alot (more than normal)...

    Now i've contacted the garage that sold it to me and he said he'll take a look at it etc...he didnt sound to enthusiastic on the phone to be honest so i dont think i wanna go down that route also i dont fancy a 80 mile round trip and losing my car for a dayor two is alot of hassle!

    i was just wondering if anyone had any past experince with these sort of symptoms?

    Any help apperciated :)

    Thanks
    #1
  2. mike foster
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    mike foster Fossie

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    That symptom has been found to be a faulty injector wiring loom.

    Not a major replacement if that's what it is.

    The car needs a diagnostic scan first to see if there is anything obviously wrong.

    Good luck
    #2
  3. Rigla
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    Rigla S Line

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    Thank you sir!
    #3
  4. mike foster
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    mike foster Fossie

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    You're welcome

    Hope that's all it is
    #4
  5. Rigla
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    Rigla S Line

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    Me to :)
    #5
  6. S3 MRU
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    S3 MRU Member

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    My car feels a bit lumpy when sitting at lights. and the rev counter bounces slightly???
    #6
  7. devonmikeyboy
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    devonmikeyboy As far from JBS as possible !

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    The 2.0 PD140 BKD engine does have a slightly bumpy ideal which makes the rev counter bounce slightly. If you find it annoying best thing to do is just raise the tick over limit by a few hundred which cures the problem.
    #7
  8. scottie123
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    scottie123 (●̮̮̃•̃) (●&#

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    Never thought of that. Nice one Mikey!
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  9. mike foster
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    mike foster Fossie

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    I've set mine to 840 rpm and that seems fine cold and hot.

    Need VCDS ( was Vag-com ) to do it tho'.

    Cheers
    #9
  10. scottie123
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    scottie123 (●̮̮̃•̃) (●&#

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    :icon_thumright:
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  11. S3 MRU
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    S3 MRU Member

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    Excellent. never knew you could do this. Just need to find someone local with vagcom!!
    #11
  12. AudiA3BE
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    AudiA3BE A3 Black Edition (Black)

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    I had a 1.6 FSI that has the same problem (Clunky Idle and heavy engine shaking, After 2 weeks in the garage and completely new injectors the fault was fixed. The car had done 58k and was 3 years old) Luckily it was all covered under warranty with labour and parts the warranty bill came to £5.5k ouch!

    Good luck with solving the problem! keep us updated!

    Mike, How do you set your idle rpm in VAGCOM?! :)

    Chris
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  13. mike foster
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    mike foster Fossie

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    It's so long ago that I did it I've just forgotten !!

    I'll do it again and get back asap.

    Cheers
    #13
  14. SAiLO
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    SAiLO Enthusiast

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    #14
  15. mike foster
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    mike foster Fossie

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    Ok - maybe that works for A4 etc but not my A3 !

    This is for version 908 :-
    Ignition on - engine off

    Select Engine controller 01
    Select Measuring blocks 08
    Select 'Go' in Group 1
    Start Engine ( you may be able to start engine earlier but I don't )
    Hit 'Turbo' button at top of page
    Select 'Done'
    Select Adaptation - 10
    Change channel to 06 and hit 'Read'

    First figure shows actual rpm
    Stored value shows rpm as originally set ( mine is 840 )
    New value will show same figure

    Use up/down buttons to change revs and when happy press 'Test' to see if ok

    If ok then hit 'Save' and close otherwise fiddle around with revs and test until happy.

    Here endeth the lesson !! This works on my '06 2.0 TDI Sport

    Good Luck :beerchug:
    #15
  16. devonmikeyboy
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    devonmikeyboy As far from JBS as possible !

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    Nice write up mike foster.:icon_thumright:
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  17. mike foster
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    mike foster Fossie

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    Cheers Mikey - we try to help
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  18. Rigla
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    Rigla S Line

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    Update, I showed the problem to a mechanic, he said it sounds fine but when he sat in it he noticed the rough idle feel...He said either Injector wiring loom or vacum leak...it feels rougher when the car is on a slope aswell. He couldnt diagnose it without a engine management light out either...

    So i might have to buy a injector wiring loom to see if that cures it.

    I'll update when ive fitted it.
    #18
  19. Milly
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    Milly New Member

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    Did you get a solution to this? My A3 TDI is doing exactly the same thing - the garage ran a diagnostic test and told me there was nothing wrong with it. Mine is also much worse on a slope.
    #19
  20. vw754
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    vw754 vorsprung Durch Technik

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    sorry i have a bkd engine and mines idles 100% the rev dont even move a bit on idle,it shouldnt be bumpy idle,it didnt leave the factory like that.
    #20
  21. a8 tech back
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    a8 tech back Member

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    Numerous causes and in some cases its normal egr bounce

    check mvb 13 for injector readings and they should be uniform with a/c switched off lights off and fan off

    check mvb 4 for valve timing angle, if retarded on the exhaust cam it will also cause this

    adjust exhaust cam to smooth over idle only if there is no dpf fitted

    blank egr off and check if this improves the idle, if it does remove the egr system and clean or post engine ecu sw version for possible sw update for egr cycle

    if none of these have worked then check fuel pressure out of the tandem pump at idle when warm and ref fuel temp and coolant temp

    check also fuel content for soot or oil

    if soot is found and its excessive then you have combustion blowpass at the injectors, either the seals are deteriorated or the cylinder head injector seats are pitted and allowing fuel/compression to pass albeit slightly but enough to cause erratic idle

    if you have access to remap tools alter the fuelling and again compare


    so its either exhaust cam timing issue/egr flow or injection duration as this is reduced to minimise consumption
    or
    fuel contamination/blowpass

    or its normal egr bounce due to combustion affect from dirty air in the chamber

    hope that helps

    i had the same issue with golf v bkd but i flashed the ecu as per vw tpi 2005869/12

    Engine: erratic idle speed in warm condition

    simply purchased the flash cd from vw and ran it on my vas and it sorted it out as it increased the fuel

    audi offer ecu updates but not specific for this complaint as there ecu software differs from vw

    all the above need to be looked at
    Last edited: Jun 26, 2011
    #21
  22. tdi-man
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    tdi-man Active Member

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    did u not need to put a security code in mike ?
    #22
  23. tdi-man
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    tdi-man Active Member

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    also any ideas how much the update puts the fueling up a8?
    #23
  24. a8 tech back
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    a8 tech back Member

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    Not sure but for golf v bkd this flash works.Wife kept moaning about it so I checked everything then found the tpi on elsa win but local vw didn't know about the flash so I go in touch with one of my old techs who ordered the flash disc for me and I ran it on my vas 5052

    Fault cured but for 8p A3 if everything checks out then advancing the exhaust cam slightly sorts it out, it has to be bucking and not just a little egr blip.

    This will also increase the idle speed to around 900 rpm or find a remapper who can alter the fuelling, I had a file for the poor warm start rpm crank speed to slow that would work as this overcame the injectors staying shut when the starter rpm dropped below 250 rpm


    the vw refalsh does not work for a3 even though the ecu part number is the same
    Last edited: Jun 26, 2011
    #24
  25. Ash187
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    Ash187 Audi Retrofitter

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    I have had this issue for over a year now and almost lost hope in diagnosing the issue.
    I will try out the Engine adaptation later today and see if that helps.
    Roughly how much are looking at for Injector looms?
    #25

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