89 200q ISV function

[jesper moreau]

>From what you say, I would really tend to think your issues are
elsewhere. Sounds like your Isv is working, just being given the wrong
instructions, if you know what I mean. I would prefer to believe your
problem lies with the Idle/Wot switch located on the throttle body. on
a properly functioning CIS system, if you unplug the Idle/Wot switch,
the Idle goes up. So either the solder breaking inside of the switch
or loss of continuity to the switch (eg. broken wire) will raise that
idle.

My other guess would be an ait leak either in you intake hoses
(michelin man, throttle plate boot, intake elbow to turbo, turbo to
IC) or a breather hose (commonly the T on the valve cover, or the
drivers side block to T hose)

 As fot thatIdle WOT switch, there is an updated replacement available
that doesn't break so easily. part no. "0 280 120 308" by bosh of
course. SJM has them as does adirondack-german auto parts.
HTH
good luck
Let me know what you found

On 10/4/05, Ed Kellock <ekellock at gmail.com> wrote:
> My ISV is keeping the idle speed elevated most all the time once the engine
> warms up most of the way.
>  It's operation seems appropriate when cold and warming up, then it'll keep
> the idle at 1000 to 2000 until I blip of the throttle.
>  I've cleaned it very well. I even made a rig with a 9 volt battery and a
> switch to keep it open so I could do better cleaning.
>  I don't believe my issue is due to any crud in it anymore because when the
> idle seems elevated, even if it's only 1000 rpm (no a/c or rad fan running),
> if I unplug it the idle immediately drops to a steady, even 800.
>  So I'm trying to figure out what might be triggering it to raise the idle
> speed when it doesn't seem necessary. I'm going to have a look at the wiring
> diagram this evening, but I thought I'd post to see if anybody has any BTDT.
>  Thanks,
> Ed
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--
Jesper Moreau
'88 5KTQ rocket
'86 5KTQ stocket