More NF idle problems - more specific

[Ben Swann]

If I recall correctly, this ISV is either bipolar or three wire and adjusts idle up and
down.  The circuit will not be enabled and will not function correctly if the idle
switch or circuit is defective. 

Let me know what you find.  I can pull the factory service guide out that describes it
in more detail – but behind schedule right now, so check that first.  I haven’t dealt
with NF/NG since Project GTQ #1, but recall getting rid of an idle hunting problem that
drove me nuts for awhile was due to a flaky idle switch.  This switch can generally
cause problems on most of these cars and does it in different ways on the 5000’s, 4000’s
and turbo quats.

You may find some wiring details off this page:
http://www.gtquattro.com/GTQDetails.html

Ben
www.gtquattro.com

[Date: Thu, 11 Oct 2007 16:29:34 +0200
From: "Eyvind E. Spangen" <200q20v at bluezone.no>
Subject: More NF idle problems - more specific
To: <quattro at audifans.com>
Message-ID: <000601c80c13$24f4e400$6edeac00$@no>
Content-Type: text/plain;	charset="windows-1250"

I removed all the hoses on my NF engine today to check and clean them. They
were all fine. I messed around a bit more and discovered something:

When I first start the car with the ISV connected, it will jump straight up
to around 2000 rpm, stay there for a few seconds and then go down to around
400 rpms, sometimes stalling too. If I unplug the ISV, the car will idle
almost like it should, just a bit higher. (around 950-1050 rpm)

It looks like the ISV is causing the trouble. I've cleaned it and it looks
just fine inside, but is there a possibility that the ISV itself is broken?

-- 
E. Spangen]