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2.0 TFSI - lumpy/ uneven idle after Timing Belt service & underboost fault!!!

Discussion in 'A3/S3/Sportback (8P Chassis)' started by akash_sky1, Apr 17, 2010.

  1. akash_sky1
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    akash_sky1 Active Member

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    [Apr 17, 2010]
    Alright lads an lasses got a bit of a strange problem here which haven't yet figured out.

    Jus had my regular filters & fluids changed and also the Timing Belt replaced- as car is now 5 years old although under the mileage recommened for replacing the belt.
    Immediately after driving away (was late for work so couldnt return) the engine management light came on, and stayed on for the next 65 miles.
    During this time there was a huge loss in power , incosistent jerky idle as mentioned and inconsistent turbo boost.

    The boost problem seemed exactly the same as on my Bora when the manifold pressure sens. was knackered and the boost was wavering all over the place. On returning to the garage as would be the case the fault dissappeared and the power was back to normal. Note this has never happened before and occured immediately after the service. This fault has now gone away for good , just happened that one time,

    Now although the power & boost seem totally fine, the lumpy, hunting idle is still present. The garage have checked it twice with no faults showing up, the battery and throttle have been reset to try cure it but this didn't really have an effect.

    So then the mechanic and me went for a flat out spin with the VCDS or something logging, and both of us felt the car was rapid as fook. Especiallly to me as I was now in the passenger seat, pulled cleanly right past 7k with no surges.

    From the seat of the pants , compared to similarly powered cars ive had plenty of experience in ( Z4 coupe 3.0si, S60 T5) I couldnt say its missing any horses, and feels as fast as it should.. BUT after the run the first and only fault code to be found since this idle problem occured is one that recorded an UNDERBOOST fault, suggesting a turbo problem.

    Another 2.0TFSI was in having a turbo replaced due to the same fault, and hoping mine isnt needing one too :-(

    Can anyone share there ideas here please? cheers
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  3. akash_sky1
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    akash_sky1 Active Member

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    [Apr 17, 2010]
    bump
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  4. navnayyar
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    navnayyar Member

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    [Apr 17, 2010]
    will be a air leak some where, check pipes from turbo to intake manifold. check recirc valve
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  5. KRL
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    KRL Member

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    [Apr 17, 2010]
    As above, it sounds like you have a boost leak. Hunting idle is one of the symptoms of a PCV failure so check that.
    #4
  6. akash_sky1
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    akash_sky1 Active Member

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    [Apr 18, 2010]
    Thanks il mention it to the mechanic, hopefully they can find where it's coming from. Almost certainly it was caused by something they dislodged during the service.
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  7. akash_sky1
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    akash_sky1 Active Member

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    [Apr 19, 2010]
    is it also likely that the underboost fault could be caused by the crappy pre update diverter valve not being able to cope under the extra heat/pressure of my remmapped car under sustained load?
    #6
  8. Jay88
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    Jay88 Member

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    [Apr 24, 2010]
    Hi just wondering how you got on with the car. What was the causing the problem in the end?

    :)
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  9. akash_sky1
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    akash_sky1 Active Member

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    [Apr 24, 2010]
    Still haven't had it back to the garage yet :-( its running normal apart from the uneven idle which is annoying in traffic...
    #8
  10. dean_watford
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    dean_watford Member

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    [Apr 25, 2010]
    Hi,

    I had exactly the same with my 2.0TFSI.

    Garage ran it up on the computer and found a bucket load of faults. They replaced a split pipe and a busted O ring which solved the issue of the lumpy ride. Also recommended replacing something called the Intake Flap Motor but that was just what the computer was telling them....

    I declined unless the error codes and management light comes back.

    Usually lumpy idle means air leak.....
    #9
  11. akash_sky1
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    akash_sky1 Active Member

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    [Apr 25, 2010]
    whereabouts was this pipe? thats what I was thinking, but it happend immediately after it was serviced!
    #10
  12. dean_watford
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    dean_watford Member

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    [Apr 25, 2010]
    I don't know....garage sorted it.

    If it happened right after service always the chance they have knocked / removed something and not put it back. Was it Audi?
    #11

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