Re: Audi 5000s Idle Stabilizer Valve

[orin@netcom.com (Orin Eman)]

> >From the obvious, I'd say the valve is for smooth idling when the engine 
> is cold. The thing obviously works, but I'm thinking its supposed to shut 
> off when the engine is warm, and its just not doing that. If I were to 
> keep this sucker plugged in (as is), I'd wear out my brakes in no time, 
> and I'd have to wonder what it would do to fuel economy. 

The valve has two purposes, to give the engine some extra air when the engine
is cold and to stabilize the idle when the engine is warm.

> 
> Think its simply a matter of adjusting something, or is the valve dead?
> 

There is a procedure in the Bentley manual for adjusting it.  Basically, you
put a meter in series with it and check the current while the car is idling.
It should be (for my car, a 5kCSTQ) 430mA +/- 20mA.  You can try to get it
in line by adjusting the screw on the throttle body.  It that doesn't work,
some people have had good luck taking it off and cleaning it out with
carburettor cleaner/WD40 and trying again to adjust it.  You should also check
that the idle switch on the throttle body is working.

I just adjusted mine.  My idle had snuck up to 1100rpm.  I improvised a test
adapter using a couple of miniature alligator clips soldered to some hookup
wire and used a Digital MultiMeter.  It showed the current to be around
390mA.  I adjusted the idle screw on the throttle body until the meter read
430mA and lo and behold, the idle was at 800rpm, right where it should be!

Orin.