Re: ...the mystery of the stalling 20v Coupe Quattro

[John Graham <jgraham1@erols.com>]

Peter Schulz wrote:

> Hi folks!
>
> My frustration with the off-load stalling of my CQ continues...
>
> To reiterate, my coupe quattro will stall randomly when the car
> is taken out of gear, as when coming to a stop. RPMs drop to
> 0, and then the idle restabilizes.  Sometimes.  Other times
> it completely stalls out. The is most evident
> when, for example, pullin into a parking spot...This happens
> on Dry days and wet days, engine hot or cold.
>
> I've removed and cleaned the ISV repeatedly with brake cleaner
> and carburetor cleaner ( It's two years old). I removed and
> lubricated the solenoid from the ISV
> I've cleaned the contacts. Chris Semple at Autobahn downloaded
> the fault codes.  They came up 4444 (ok).
>
> The car has the updated crankcase breather hose.  I've tried the
> butane torch (unlit of course) check on the vacuum lines. (at least
> the ones that I've been able to identify. Bentley is NOT alot
> of help here.)
>
> When I disconnect the ISV lead, the engine immediately bucks, then
> stalls.  If I reconnect it before it completely stalls, the car
> idles normally.  Without the ISV connected, the car will not start.
>
> When it's not stalling the car idles normally.  No wander, no drift.
> O2 sensor is two years old. Gas filter is 1 year old.  I usually run
> the car on Texaco 93 octane.  Trying different gas and different
> stations has not made a difference (tried Mobil for a while). Cap,
> rotor, plug wires, plugs are two years old.
>
> HELP! My wife refuses to drive the car because she's afraid of it
> stalling repeatedly in traffic.
>
> Thanks for any advice!
> -Peter Schulz
> 1990 Coupe Quattro
> schulz@ed.ray.com

 What type of spark plug are you useing. It must be the three electrode
type. NGK BCP6ET or Bosch
F6DTC. Also was the idle set with the computer in open loop? If not, the
ISV will never work right.
It's the only way to center the ISV.  To set it in open loop, jumper 1a
and 1b of the computer under
the dash to the left of the clutch.



John
1990 CQ