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VYII 3.8 Idle issue.

Discussion in 'VY Holden Commodore (2002 - 2004)' started by Ralphski, Jul 22, 2016.

  1. Ralphski

    Ralphski Ralphski

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    Hi all,

    I've googled the world for this with no joy.... Hope someone here's experienced this & is in 'the know'...

    2004 VYII 300k's (I've had it since 140k's) standard motor (ex Pol car, factory LPG), auto, only change I've made is from vaporized LPG to injected LPG.
    Coils are less than 20K old
    Plugs & leads less than 40K old (platinum iridium plugs)
    No check engine warnings
    The problem happens on both LPG & petrol.
    When the engine is hot (normal operating temp, never when cold) sitting in park/nuteral or drive.
    At totally random times the rpm will suddenly drop, then recover. Only once has it ever dropped enough to make it stall (in drive, stationary stuck in traffic).
    I've checked for vacuum leaks, nothing heard/seen.

    I'm out of ideas (fyi, I'm not a complete newb, I did my apprenticeship in the early 90's just been off the tools since 00).
     
  2. caaf

    caaf Member

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    Crank angle sensor? I know in the VN days a for a non starter a good cold wet soaking closed the fault all be it very temporary.

    I guess this is a token post as I to have a 300k plus VYII. Touch hairy wood the old girls putting along ok ;)
     
  3. EYY

    EYY Well-Known Member

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    Have you checked the IAC valve?
     
  4. Ralphski

    Ralphski Ralphski

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    I've taken the IAC out & cleaned it up, a bit of carbon on it, but nothing serious. Also 'brake cleaned' the whole throttle body, took the plenum apart, cleaned it out & resealed it back on.
    No change.
     
  5. Ralphski

    Ralphski Ralphski

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    Cheers Dave, Except for the random stutter she's running like a dream :)
     
  6. SavVYute

    SavVYute Active Member

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    My VY has the occasional stumble after sitting at idle for a few minutes.
    More so after I've been playing around with the engine or have recently disconnected the battery and it hasn't had a chance to 'relearn' or fine tune itself after a few starts.
    I put it down to the engine management system switching from closed to open loop mode.
     
  7. Ralphski

    Ralphski Ralphski

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    Update...
    Replaced the IAC (had the battery off for about 15mins... IAC change & coffee).
    When I started her up (cold) idled fine. Got her hot (just like the wife :) and the problem returned... bugger!
    It's almost as though she's idling too slow & when any accessories kick in it drops the revs a little & she stumbles & then recovers.
    Next mission off to RTFM (Read The Flipping Manual), plug in the laptop & see how slow she's really going...
    To be continued...
     
  8. caaf

    caaf Member

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    Certainly seems like the lappy should be plugged in over a journey or two as it'll hopefully record something.. Nothing worse chasing ones tail!
     

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