'88 80q idle weirdness...

[radek at istar.ca]

Rand,

I have a car of the same vintage and had the same problem.  What fixed it was a few
things:
1. clean the ISV;
2. fix all vacuum leaks (not as easy as it sounds);
3. make sure the charging system works well (charging about 14V) and has good ground.
In my case it involved removing the alternator and cleaning its contact points to the
engine bracket
(it grounds through the block).

The last step also fixed a oscillating speedometer needle.  Good luck.

Radek
88 90Q
91 V8Q 5-sp.

> Message: 17
> Reply-To: <orsopers at comcast.net>
> From: "1" <orsopers at comcast.net>
> To: "'Quattro List'" <quattro at audifans.com>
> Subject: '88 80q idle weirdness...
> Date: Fri, 5 Sep 2003 20:49:09 -0700
>
> I have had my '88 80q for about 8 mos now and aside from a big hole in the
> heater core and a dead WOT/Idle switch it has run darn near flawlesly.  It
> is actually amazing to me how well it runs at 15 years/135k miles.  The only
> thing that might be considered a problem is that it idles at ~1000 rpm.  Ok,
> not much to worry about especially since the idle is rock steady.
>
> Recently on hot days (90+) when I get it fully up to temp and then shut it
> off for 30-45 minutes and then start it again the idle will surge.  1000rpm,
> 12000rpm, 1000rpm, 1200rpm at about 3/4 second per cycle.  If it sits less
> than 30 minutes no problem or over an hour again no problem.  I assumed it
> was the ISV so this evening as it was ideling I disconnected it expecting it
> to settle down.  It didn't.
>
> Any ideas?  There are no codes, and once things cool down some it will be
> fine again.  the ISV is very warm to the touch but so is everything else
> under the hood.
>
> Oh one other thing, the 1000RPM dle will drop to 800RPM if I turn on
> something that draws a lot of current like the rear window defroster or if
> the cooling fan comes on.  Also when the idle is surging it will sometimes
> settle down when the fan comes on or I turn on the rear window defrost.
> Weirdness.
>
> Thanks in advance for any help,
>
> Rand Soper
> Portland, OR
> '88 80q