85 turbo - idle going crazy

Discussion in 'General Motoring' started by mark french, Jul 11, 2003.

  1. mark french

    mark french Guest

    Idle speed keeps fluctuating for no reason, way overspeeding sometimes. Tried
    swapping in a new throttle position sensor as this worked on another one of
    these cars I had once, no change. Also when car is doing this when first cold,
    the speedometer starts reading off random numbers (??) but this seems to go
    away shortly. Am not getting any power loss light nor any stored codes. It
    definitely seems to be the computer telling the idle motor to increase
    erratically - if I unplug the idle motor, idle stays steady forever until I
    plug it back in, in fact I'm driving it like this now. It seems to vary
    between normal and various overspeeding, it is not making it go too low (not
    stalling). Any suggestion on what to check or change next? Could it be either
    of the sensors in the distributor? I changed the rotor but thats it.
    mark french, Jul 11, 2003
  2. mark french

    frenchy Guest

    Before I spend $ on the speed sensor...if I unplug the reference
    pickup, the idle drops to a steady level. Plug it back in and idle
    jumps back up and starts hunting up and down again. Does this
    indicate the problem might actually be that pickup? thanks! Mark
    frenchy, Jul 13, 2003
  3. mark french

    frenchy Guest

    Correction, I am unplugging the sync pickup, not the reference.
    frenchy, Jul 13, 2003
  4. mark french

    frenchy Guest

    AFter changing the distributor pickup I think the problem turned out
    to be some crud in the throttle body plate and/or orifices. I had
    scrubbed it while back but apparently some more must have built up.
    Idle must have been simply adjusting to fact the crud was built up in
    that area. Cleaned it and idle is steady as a rock now....Frenchy
    frenchy, Jul 17, 2003
Ask a Question

Want to reply to this thread or ask your own question?

You'll need to choose a username for the site, which only take a couple of moments (here). After that, you can post your question and our members will help you out.