Idle too high, 97 Jetta

Discussion in 'VW Mk3 Jetta, Passat TDI and other/older diesels' started by alfa4door, Feb 2, 2012.

  1. alfa4door

    alfa4door New Member

    Joined:
    Feb 2, 2012
    Messages:
    6
    Car:
    97 jetta td
    Hi,
    I am a new member here and i just acquired a 97 Jetta TDi. I have read with interest the buyer /new owner guide and the 1000 tips sections. EXCELLENT.

    My car needs a TB and a few other things. I will implement all the suggestions posted in this forum, it is a neat car with 250,000 Km, th every basic model, manual windows and all which is what I prefer.

    However, my car idles at 1100 even when at operating temperature. In addition the large black pull-out lever to the left of the steering appears to make no difference in or out at any temperature. I thought it would be like a Mercedes to raise the idle but it does not do anything.

    Why is the idle too high?
    I read here is should be 900 +/- 100 so we are not way out there but shifting is unpleasant and I worry about the clutch. Is there a way to lower it?

    What is the black pull0oul lever supposed to do?
    When is best used and can it be adjusted?

    The car is a little hard to start. Should I replace the glow plugs as a matter of course?

    I looked and looked and did not find an answer, so here I am.

    thanks, Andrea in BC
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  2. Seatman

    Seatman Active Member

    Joined:
    Jul 9, 2010
    Messages:
    5,222
    Car:
    2000 Mk4 Golf Estate 1.9tdi 174 bhp
    Location:
    Scotland
    Mods:
    PP764's, turbo and mapping
    Sounds like the coolant temp sensor might be busted, it raises the idle speed. Does the glow plug light stay on for long or just a couple of seconds?


    welcometomyturbodies
  3. alfa4door

    alfa4door New Member

    Joined:
    Feb 2, 2012
    Messages:
    6
    Car:
    97 jetta td
    HI Seatman,,

    i thought about something like that, the glow light stays on several seconds, what appears normal to me.

    Where is the coolant sensor, maybe I could disconnect it with the car at working temperature and see if it makes a difference.
  4. Seatman

    Seatman Active Member

    Joined:
    Jul 9, 2010
    Messages:
    5,222
    Car:
    2000 Mk4 Golf Estate 1.9tdi 174 bhp
    Location:
    Scotland
    Mods:
    PP764's, turbo and mapping
    Not sure on your car, I suspect you might have more than one, I think one of them at least is on the end of the head at the gearbox end anyway.
  5. audi1z

    audi1z Member

    Joined:
    Oct 16, 2010
    Messages:
    254
    Car:
    Audi 80 1Z Engine
    Hi,
    from your description I think that your car does not have a TDI Engine, but a TD Engine with turbulent chamber injection, Motor Code AAZ (?). The pullout lever is a cold startig aid, which changes injection timing towards early and increases the idle running speed.
    With warm engine, you should get a harder ingnition noise when the lever is pulled out. Cold engine start is hard when the lever is not pulled.
    Injection timig and idle running speed are adjusted manually.
    Perhaps you can identify the motor code and post a picture of the injection pump, to put us on the safe side for further discussion?
    Cheers
    Audi1Z
  6. alfa4door

    alfa4door New Member

    Joined:
    Feb 2, 2012
    Messages:
    6
    Car:
    97 jetta td
    engine identification

    yoiu are correct, the valve cover sticker reads "AAZ 735 386"

    regards, andrea
  7. alfa4door

    alfa4door New Member

    Joined:
    Feb 2, 2012
    Messages:
    6
    Car:
    97 jetta td
  8. alfa4door

    alfa4door New Member

    Joined:
    Feb 2, 2012
    Messages:
    6
    Car:
    97 jetta td
    AAZ idle adjustment

    I have found the idle screw for the AAZ pump on line I thought I would post it for future reference.

    here is the image that speaks for itself

    [​IMG]

    thanks to Mattley of the SEAT CUPRA NET
  9. audi1z

    audi1z Member

    Joined:
    Oct 16, 2010
    Messages:
    254
    Car:
    Audi 80 1Z Engine
    Hi,
    this image makes the idle speed alignment easy.
    - check that the cold start aid is completely shifted in and that the lever is at its stop;
    - adjust the idle speed with -1- to 900 +/- 30 min-1;
    - if not possible, loosen the counter nut of -2- and turn -2- back to give the idle speed lever some space, retry with -1-;
    - turn -2- forward until contact with the idle speed lever, fix it again;
    - pull cold start aid completely out;
    - adjust -4- to get 1050 +/- 50 min-1;
    Cheers,
    Audi1Z
  10. alfa4door

    alfa4door New Member

    Joined:
    Feb 2, 2012
    Messages:
    6
    Car:
    97 jetta td
    idle sttign sequence

    thanks and best regards, Andrea

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