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Loss of power

Discussion in 'A4/A4 cabriolet/S4 forum(B6 chassis)' started by Mollygoogle, Dec 18, 2013.

  1. Mollygoogle
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    Mollygoogle Member

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    [Dec 18, 2013]
    Some of you may have seen my recent thread about a new head gasket and head skim on my 1.9 130. Since the work was completed the car is noticeably down on power. The car struggles to start cold which it didn't before. Throttle response is erratic at times, power comes in surges. The car struggles at all revs. There is not a noticeable point that the turbo comes in, it's almost as though it doesn't work.

    What are peoples thoughts on causes? Of course the garage say that nothing they have done has caused it but it went in driving sweet as a nut and came out like an asthmatic n/a old diesel.
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  3. stu_m
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    stu_m Active Member VCDS Map User

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    [Dec 18, 2013]
    has the cam timing been checked?

    they haven't used the old method of a bi of tipex have they?
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  4. desertstorm
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    desertstorm Well-Known Member

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    [Dec 19, 2013]
    There could be many reasons for the issues you are seeing.
    They may have disturbed / knocked off a vacuum pipe for the VNT mechanism on the turbo. This would cause the lasck of power.
    Starting issues could be related to the cam timing which is critical on a diesel. Can be checked with VAG-COM

    How to adjust camshaft timing on a TDI PD pumpe duse 1.9L engine (VW and Audi) - YouTube

    Do you know how much was skimmed off the head as you can take only a very small amount off these. If it went in driving sweet as a nut why was the head gasket changed ?.

    Karl
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  5. Mollygoogle
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    Mollygoogle Member

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    [Dec 19, 2013]
    The gasket was changed as it was losing coolant at a rapid rate, though driving wasn't affected.
    I've checked with the garage and the timing was not touched. They insist that timing doesn't need to be done. They have justified this by saying it started first time after the rebuild, though I don't see how that is relevant. The car is going back in at the weekend to have the timing done at my insistence.
    Initially after the rebuild the car wouldn't run over 3000rpm, after advice on here I got them to swap over the vacuum pipes and it then ran better but still isn't right.

    I'm trying to get as much info as possible as the garage are arguing that they aren't responsible yet it is clear to me that if something has been disturbed or the timing hasn't been done when it should that the responsibility lies with them.

    Does anyone know if it is standard VAG procedure to check the timing of a 1.9 after a skim?

    Ps the garage inform me that the skim was minor and precautionary after previous experiences of issues with a head that they didn't have skimmed
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  6. B5NUT
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    B5NUT Well-Known Member VCDS Map User

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    [Dec 19, 2013]
    VAG TDI heads should not be skimmed, the compression ratio and the squish band will have been changed by skimming, you could fit a thicker head gasket but that may not fix the issue. I would go back to the garage and get them to fix the problem or by a new/recon head.

    Which garage in Darlington did this so I can avoid them? PM me if you don't what to make it public.
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  7. Mollygoogle
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    Mollygoogle Member

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    [Dec 19, 2013]
    Is this a VAG policy or just perceived wisdom? I ask as I have spent hour after hour trawling the net over the last two weeks and it's pretty much a 50:50 split between those that say not to do it and those that say it is absolutely fine but I have been unable to find anything official to say yes or no. Does anyone have access to a genuine VAG document, workshop bulletin, etc that states that the head should not be skimmed? I can see this turning in to a real battle and I want to be armed with all the relevant info before I start fighting
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  8. desertstorm
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    desertstorm Well-Known Member

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    [Dec 19, 2013]
    Looking on the Workshop repair guide on ElsaWin for the 1.9 130 engine it doesn't mention anything about machining of the head. For the 2.0 16 valve engine it does state that the head cannot be machined.
    Quite often all that is done is just a precautionary skim to make sure the face is flat and this will also clean up any corrosion or old gasket/sealer.
    You have to take the cam belt off to change the pump so the timing is disturbed

    Karl.
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  9. Mollygoogle
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    Mollygoogle Member

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    [Dec 19, 2013]
    Thanks for taking the time to check that for me Karl, it's much appreciated. The guy in the garage had it done as a precaution for those reasons and stated that he had encountered previous difficulties with a pd head that wasn't skimmed before refitting.

    Does a pump have to be changed as part of the process?
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  10. stu_m
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    stu_m Active Member VCDS Map User

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    [Dec 19, 2013]
    so if the timing wasnt touched then how the hell did this monkey get the head off?

    if the belt is removed you have to set the timing as per manual otherwise it WILL be out as soon as you put tension on the belt it will move the timing!

    from the sounds of the replies from the "mechanic" he doesnt sound all that clued up to me

    take to someone who knows these cars

    or if you have access to VCDS then you can check the syncro angle to see if its out you cant actually check timing on the 1.9 with vcds but if the syncro angle is out this is a sure thing the timing is off
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  11. Mollygoogle
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    Mollygoogle Member

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    [Dec 19, 2013]
    His answer with regards timing was that there was a plate that you undid, then tension the belt and tighten the plate back up. All sounded a bit simple and unexact to me but I don't know a great deal about engines as you can tell

    I have already determined that I will be using a local VAG specialist from now on (I've moved close to a specialist but stupidly kept allegiance with my old mechanic who used to be amazing but really seems to have lost the plot on the last couple of jobs)
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  12. B5NUT
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    B5NUT Well-Known Member VCDS Map User

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    [Dec 19, 2013]
    A friend who is a master tech at my local Audi dealer, he helped with my HG failure also stated not to machine a VAG TDi head, as I did ask if this should be done, and after checking with my copy of elsawin it also states "Reworking diesel cylinder heads is not permissible"

    As stated above you have to remove the head to change the gasket, then clean up the surfaces as their is always **** left over from the old gasket, so the head has to come off. I also had to check the syncro angle on my car even the the cams locked in place the timing was still slightly out but not by much thankfully easy fix with the help of vcds.
    Last edited: Dec 19, 2013
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  13. stu_m
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    stu_m Active Member VCDS Map User

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    [Dec 20, 2013]
    this to me set alarm bells ringing

    first he says he never touched the timing then he says he has done the above which is setting the timing!!
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  14. desertstorm
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    desertstorm Well-Known Member

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  15. Mollygoogle
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    Mollygoogle Member

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    [Dec 27, 2013]
    thanks for that, it's in the garage at the minute so hopefully it gets sorted
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