Rough Idle on Cold Start

Discussion in 'General Motoring' started by KLB, Apr 16, 2006.

  1. KLB

    KLB Guest

    I have a 1994 940 turbo Wagon

    Working very well but has quite a rough idle on cold start, almost chokes
    out.

    On a warm start all is well.

    Where would anyone suggest that I start looking?

    Plugs and air filter are new

    Thank you
     
    KLB, Apr 16, 2006
    #1
  2. A good place to start is by cleaning the throttle body and idle air control
    valve (the cylindrical air valve under the throttle body. They tend to get
    fouled with deposits, especially the idle passage from either side of the
    throttle plate to the thumbscrew underneath. Cold stalling is a typical
    symptom for dirty throttle bodies.

    I remove my throttle body for thorough cleaning (takes about half a can of
    carb cleaner!) but it can be done on the engine.

    Mike
     
    Michael Pardee, Apr 16, 2006
    #2
  3. KLB

    KLB Guest

    Thanks Mike

    This cleaning was or is on my to-do list and although it can be done on the
    engine I was sort of thinking of doing the whole works, hence yanking it
    off. Car is new to me and I would like to get an idea of just how dirty
    everything is.

    Any idea about my other post (replacing air intake) as it relates to this as
    well.

    Thank You
     
    KLB, Apr 16, 2006
    #3
  4. KLB

    KLB Guest

    Took the car out to my mechanic last weekend and he removed and cleaned the
    throttle body (somewhat dirty, smaller of the two ports was plugged)

    Rough idle is better but not gone away.

    What should a fellow look at next?
     
    KLB, May 4, 2006
    #4
  5. KLB

    Steve Guest

    Gwen Stefani, Catherine Zeta-Jones, or Angelina Jolie would smooth most
    things out IMHO :)

    ---might help if you told us what kinda car, what year, have you done the
    obvious fuel and ignition system maintance and how many miles are on the
    car.
     
    Steve, May 4, 2006
    #5
  6. KLB

    KLB Guest

    Sorry, Sorry

    For a minute there I thought you were all mind readers.

    Car is 94 940 turbo wagon, 110,000 miles, is not the Regina System.

    Replaced plugs, wires, air filter, removed and cleaned TB so far. Volvo
    just popped in new crank sensor via recall.

    Runs great when warmed up, just a rough idle on a cold start. Idle stays
    below 1000 during cold start, I would guess some where around 750 rpms.
     
    KLB, May 4, 2006
    #6
  7. KLB

    Steve Guest

    Cap and rotor? I know it's a bitch to get to!
     
    Steve, May 4, 2006
    #7
  8. Try cleaning the Idle Air Control Valve and checking the MAF for
    cleanliness. Some air filter housings collect a large amount of plastic foam
    dust which can affect the MAF.

    All the best, Peter.

    700/900/90 Register Keeper,
    Volvo Owners Club (UK).
     
    Peter K L Milnes, May 5, 2006
    #8
  9. The mark of a seasoned shadetree mechanic!

    Mike
     
    Michael Pardee, May 6, 2006
    #9
  10. KLB

    Steve Guest

    From their new commercial I think some Heineken light would also help
    immeasurably... :)
    (you have to drink imported beer to fix an imported car, no?)

    --Steve (who has yet to find a brew to exceed the unique wonder of
    Dortmunder Union Dark, although Becks will work in a pinch (started drinking
    those when I had VW's - Do I need to change to one of these?
    http://ohhh.myhead.org/list/2c-swe.html )
     
    Steve, May 8, 2006
    #10
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