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Re: Idle Stabilization Valve correct operation
Mirrors my experience. Except that I broke my coolant bleeder screw today
while changing the fluid - damn plastic. :-( Temporarily replaced with a
bolt. "Placebo", huh? Better than "Ibizia" or "Octavia"...
At 08:43 PM 8/16/1998 , Phil Rose was inspired to say:
> Now I've had a chance to peer into the bowels if my '91 200's ISV, and I
> revise my earlier suppositions. I, too, see an opening about the width of a
> nickel (uh, about 1.25 mm--for the numismatically challenged). There was
> quite a bit of black crud showing on the cylinder surface, but application
> of 9V could move the mechanism easily to and fro. Many on/off cycles failed
> to diminish the size of the ISV opening at the "rest" (off) position. I
> seemed to hear the rotation stop with a resounding "clack" as the shutter
> hit the limit screw.
> I applied several squirts of carburetor cleaner. I repeated the 9 volt
> jolts some more, and convinced myself that things were moving freely and
> weren't gonna change. The opening _could_ in theory be closed up by use of
> the potted adjustment screw. But why? Could the original adjustment
> actually have "worn" away to the extent of a 1.5 mm opening? I think not.
> The adjustment screw has a broad, flat end, and I doubt Bosch would be dumb
> enough to have designed a "pointy ended" screw for this application. So I
> think the ISV opening is the way Bosch set it to begin with. Also it's
> cemented in place and virtually impossible to turn (as reported by Brett).
> If the screw _could_ be turned, its fine thread would require at least 3
> full turns to eliminate the "gap". I left it alone and reinstalled the ISV.
> Damn, I think the car runs better. Maybe I oughta rename it "Placebo". But
> that sounds a little too Spanish for a German car, dontcha think?
88 90Q - <insert pithy witticism here>
88 Golf GTi - PRO Rally