Timing? = '89 100

[Swann, Benjamin R. (BSWANN)]

Jim,

Since no one else commented yet, I'll give it a shot.

I dont think there was any damage running it in diagnostics mode, although,
this probably made for som interesting running.

This probably faked out the ISV to override whatever problem exists and put
the ECU in a more or less fail safe mode.

I would check your Throttle body switch(WOT/Idle) and also verify that you
are getting voltage to the center lead(double check this with the Bently
diagram for your make and year).  I say this, because I replaced my switch
uncessarily, only to find out there waw a broken wire under the rubber boot
in the connector to the switch.  This broken wire not only messed up my idle
as you describe, but also disabled WOT enrichment.

Refer to archived posts on "High Idle problems ..5KTQ - solved" for details
on the extensive troubleshooting I did, and suggestions from others.  This
may cover other things that what I found as my culprit.

BTW, timing on these cars is not adjustable by conventional means.  If the
distributor was turned it may be close to out of its window.  The
distributor needs to be as close to the center of its window as possible,
the ECU does the rest based on load(Manifold Actual Pressure) and RPM.

Likewise, the idle adjustments should not be screwed with as well.

Also, ISV may need cleaning(oh you did this already), and of course check
all the basics first, incl, Vac lines/leaks, install fresh Air Filter and
clean sensor plate, to achieve the side benefit of uncovering some of the
latent problems that may exist.

Regards,

Ben Swann
'87 5KCSTQW
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Date: Thu, 07 Sep 2000 12:03:44 -0400
From: jDolan <jhdolan at sover.net>
To: quattro-digest <quattro at audifans.com>
Subject: Timing? = '89 100

I've been asked to sort out a 1989 model 100 that is running poorly.
The idle was ranging widely, and it had no "oompfh." I found a bad vacuum
hose, cleaned the ISV and went over all the obvious things: grounds, wires,
etc., and it now idles in the range of 1000 rpm's, but does tend to "hunt" a
bit. It still is a bit sluggish, and I suspect part of the problem is the
cat bing stuffed up.
 My main questions/considerations are: When the vehicle came to me, it had a
fuse in place in the fuel pump relay, and it was being driven that way. When
the fuse is removed, the idle ascends to the range of 2000 rpm's. I'm
thinking that the vehicle was timed/setup with this fuse there. Should I
just remove it and re-time the motor? Is there a recommended website that
might have particulars as to how to do this? I don't have a Bentley's. If
anyone wants to offer advice, I'd certainly and welcomely receive it.
And finally, would sustained operation with that fuse in place permanently
damage anything? I have no idea how long it has been there.
 Thanks for any help offered.

jim   '88 90q  w/263K miles.