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2.0 tdi lumpy idle with bad smell from exhaust/engine

Hutchball Jan 14, 2018

  1. Hutchball

    Hutchball New Member

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    Hi there. I hope someone on here can point me in the right direction. I’ve been reading all kinds of threads but with no definite answer.
    I’ve had the car about three months now and I thought it was just the smell of a diesel but today I was told how smelly the exhaust was at a drive-thru! He said he could hardly breath! I have to put the re-circ on if I’m sitting in traffic.

    There is some white smoke coming out the back but with the cold days it’s hard to say if that’s normal. It smells like a ‘pungent’ smell, like something’s getting red hot.

    Also it suffers from quite a lumpy idle, the engine ‘kicks’ (like a misfire) until it’s fully warm.

    Thanks for any help.
     
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  3. Hutchball

    Hutchball New Member

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    It’s a BRD 2.0 TDi PD engine if this helps.
     
  4. Mario

    Mario Active Member Audi A4 quattro TDi S tronic S-line owners group Manual

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    Remove the fuel filter and drain it's contents into a clear glass jar. If it's black (means it has oil mixing with diesel) then that is your issue.
     
  5. Hutchball

    Hutchball New Member

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    Thanks for that. Will do that tomorrow.
     
  6. JonSline

    JonSline Considering the next mods.....

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    Indeed, sounds to me like injector seal failure, the Black is from combustion gasses mixing with diesel. Via the fuel return gallery in the head. The copper washer/seal at the bottom of the injector tube is likely to be leaking.

    Assuming you can still get the injector out then it’s a relatively easy job to do.
    VCDS can give you injector balance figures which can help point towards the faulty cylinder.

    In a really bad case combustion gasses can erode the liner of the injector tube so it worth attending to sooner rather than later.
    If you need a new injector I have to tell you, you want to be sitting down when they tell you the price even for a pattern one.


    Sent from my iPhone using Tapatalk
     
  7. Mario

    Mario Active Member Audi A4 quattro TDi S tronic S-line owners group Manual

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    It's not always due to injector seals. It can also be due to the Tandem Pump. The oil seals internally can deteriorate over time and cause oil to mix with the diesel.

    Both jobs cost about the same for parts (circa £250-ish), but the Tandem Pump swap is 15 minutes and the injectors seals is considerably more work! So it's up to you what you decide to try first to fix the issue.

    Either way, just remember that you need to run LOTS of tanks of clean fresh diesel through the system before it will start to clear up and get better as there will be oil residue in all parts of the fuel system (inc inside the tank).

    If it's still just as bad after several months, then it might be time to look at replacing the one you didn't do first time. I had this issue and personally opted to change the Tandem pump as it's easier. So far it seems to be getting better and doesn't smell as bad, but it's still not great. Going to give it more time though for the reasons stated above.
     
  8. Hutchball

    Hutchball New Member

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    Thanks for replies. Regarding the injectors what block on VCDS would give me more information? I’ve had a quick look and it didn’t throw any injector faults out at me.
     
  9. JonSline

    JonSline Considering the next mods.....

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    Yes, that said tandem pump failure would show as general poor performance, as a pose to rough idle, that and the you might also detect diesel in the lubrication oil.

    As regards to the vcds injector readings, only coil/solenoid faults tend to give a fault, and that tends to be the harness anyway.

    What your looking for is a balance figure, there will be four numbers (4 Cylinder) which vary with revs and should all be the same if ones out a bit that could give you an indication of which one to pull. But you may not have a bad enough problem.

    White smoke could also be a more sinister engine issue like a burnt valve, you might consider a compression test to give you a more clear idea of seal and cylinder condition.

    That being said the seals are 50 quid to do the lot in Parts just a little time consuming.


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  10. Hutchball

    Hutchball New Member

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    Could it possibly be something as simple as the cam timing out? When I bought it, the Torsion value was -2.2 and the torque curve while driving was odd. Now it’s at 0 and it’s nice and smooth now. I only adjusted the injector cam. Is it possible the valve cam is out?
     
  11. JonSline

    JonSline Considering the next mods.....

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    If it was out enough to smoke it just wouldn’t start - the electronics realise and just don’t fuel


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  13. mm707

    mm707 Member

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    Hi mate, did you fix it ? Mines exactly the same
     
  14. Hutchball

    Hutchball New Member

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    Hi mm. I’m toying with the cam timing being out. I’ve followed a lot of threads on here and it’s down to a new timing belt and the cams being ever so slightly out. Is your smelly too?
     
  15. noelpen

    noelpen Member

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    May need egg valve cleaning ??

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  16. Hutchball

    Hutchball New Member

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    I’ve had the EGR off and cleaned it. It was in a state. It may need another go over which I’m going to try this week.
     
  17. mm707

    mm707 Member

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    Yes it smells. Only does it when idling when cold.I notice it a lot when reversing into the drive. Ill take the egr off this week to clean and maybe the inlet manifold too.
     
  18. Hutchball

    Hutchball New Member

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    Hi mm707. I’ve sent u a pm I think. It would be good to get to the bottom of this.
     
  19. Hutchball

    Hutchball New Member

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    Hi just an update on this thread.
    After searching Internet forums I took a shot at the cam timing being out. I got the timing reset by Avon Tuning and it has cured the problem. I now have no lumpy idle and the idling smell has completely dissapeared. It wasn’t cheap but it’s fixed.
     
    Mario likes this.
  20. Mario

    Mario Active Member Audi A4 quattro TDi S tronic S-line owners group Manual

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    Good to know, will need to get mine done also and see if it helps. Already got VAGCOM and the tools, just need to find the time.
     

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