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Re: need an ISV

>Does anyone know
> what the effect of unplugging a good ISV would be, and what should the
> effect be of unplugging a bad ISV?

Um, it depends... On the three wire ISV like I have (and I don't even
know if all three wires are active, one may be "AC" only) the rest
position is about 1/4 open.  12v on one terminal opens it all the way,
12 v on the third closes it.  Of course it is not a static device, it
has a duty cycle and there is a test connection (at the right strut
tower) to check this.  So it is being switched on/off as fast/often as
necessary to let the appropriate amount of air bypass the throttle
plates and idle screw passage.

If it is sticking, it won't work right, cleaning seems to work sometimes
I guess (no btdt really).

If I unplug mine with a warm engine, as I recall, the idle goes up a

Not saying that is a "working" example, just that is what it does!

one of these days I will try to figure what the difference *really* is
between the two wire and three wire ISV's.

Huw Powell


82 Audi Coupe; 84 4kq; 85 Coupe GT; 73 F250