High idle speed, 4ksq....More data.

[mike mcclurg]

A little more data, and thanks so far to Huw, Ben and
Bob for suggestions.

Tested some more last night. Sure enough, the idle
switch is bad - open circuit at closed throttle.
Decided to test by shorting between the leads to the
throttle switch. This has about the same effect as
when I disconnect the ISV; that is, the idle speed is
reduced and remains steady, but still too high.
Disconnecting the ISV actually has a little more
effect.

Another thing I noticed last night is that the idle
speed is OK right after you start the car. It is only
after it warms up that the high idle speed shows up.

One more thing, I noticed that the ISV vibrates
cyclically (on a couple of seconds, off a couple of
seconds) when the key is just turned on, the engine is
not even started. Is this right?

Any more ideas? Right now, it looks like the
suggestion that the whole CIS system is suspect may be
frightfully close to the truth. The thing is, under
any driving conditions it runs beautifully...it sings.

Thanks again,
Mike

Original post:
> 
> Car is an '85 4ksq.
> Recently, it has a high idle speed, about 1400rpm.
It
> is steady.
> If I disconnect the wiring to the ISV the idle speed
> drops to what it should be, about 800rpm and is
> steady, also.
> What should I look for?
> Thanks,
> Mike
> '85 4ksq
> '89 100q


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