Re: Irratic Idling...

[rwcohn@chinet.chinet.com (Robert W. Cohn)]

> 
> At 04:08 PM 11/22/94 -0700, quattro@swiss.ans.net wrote:
> >Well after the suggestions from everyone, I went through everything and
> >can't find any vacuum leaks anywhere. So the only thing that I can think
> >of is the idle stablizer.. how much to these puppies cost? 
> >oh yeah, 89 100Q
> >
> >Any other ideas out there?
> >Thanks for all the input.
> >Shannon
> 
> I missed your first post, but I gather you have an erratic idling problem 
> which can't be found for love or money.  Join the club.  I have a 88' 90Q 
> with 138K on it that Audi has chased for 6 years trying to find a low idle 
> speed with AC on when very hot. (Like summer in Phoenix.)
> 
> Anyways, if the 100Q is like mine, check for a dwell signal across the two 
> terminals  at the stabilizer.  No signal means problems in the wiring 
> harness or computer.  On the 90Q a dwell signal should *always* be on the 
> stabilizer.  (when running of course!)  Different techs have replaced the 
> following items looking for this "missing" signal:  Idle stabilizer, O2 
> sensor, knock sensor, fuel computer, ignition computer, and potentiometer (a 
> thingy on the fuel injection control unit).
> 
> Any questions, let me know.  I have a fair understanding of the Bosch KE-3 
> Jetronic, which I believe you have as well.
> 
> 
> allanm@primenet.com
> 
> 
Also check for a bad connection at a shared ground point, used by the 
differential pressure regulator and the ignition.  Just trace the ground
wire from the diff. pressure regulator to the intake manifold.  I found
mine to be loose.  I un-screwed it by hand, ran a tap in the hole to 
clean the threads, cleaned the stud with a wire wheel, and slightly 
deformed the threads by tapping them with a ball pien hammer.  I then 
used two nuts tightened against each other to provide a suitable way of 
driving the stud into the manifold.  Some white lithium grease was used 
to prevent aluminum oxide from forming, and causing a poor electrical
connection again. 

I found this after testing the entire ignition system, and the injection
system.  The tests on the ignition and injection systems showed everything
was fine.  The problem finally got bad enough that the car would buck.
I then open the hood expecting a cracked vacuum hose.  One that would open
when the engine was under load (engine would move).  What I found was this 
connection arcing.  

Robert.....
rwcohn@chinet.com

>