5000t idle problem

Ameer Antar ameer at snet.net
Sun Nov 11 21:48:50 EST 2001

i bet it's not the valve, although it is possible. Sounds like a classic
vacuum leak. Check ALL the turbo rubber hoses for cracks...from the air
cleaner to intake, also on any hose connected to the intake, such as
intercooler, idle stab. valve hose, etc. The only real way to be sure is to
remove each one, b/c often the cracks are at the bottom and can be hidden
in folds. Oil from the turbo / crankcase ventilation often pools in the
hoses, and eventually rot the rubber parts. A vac. leak can cause the car
to stall and idle rough.

The idle stab. valve just allows air to get around the throttle valve if
the engine is cold and needs more rpm or under load, like a/c. But this air
is metered. In other words, since the idle stabilizer valve diverts air
that has already passed through the fuel metering valve, so the system
accounts for this air when deciding how much fuel to squirt. So, no matter
how open or closed the stab. valve is, you should always have enough fuel
to air ratio. Rough running is usually b/c of a very bad fuel:air ratio. My
guess is you have a leak somewhere between the air cleaner and intake, or
maybe in the hoses for the idle stab. valve...Make sure to follow each hose
and check them, but the real tiny vac. lines might not be as much an issue
to cause poor idle like that. Your problem is very common, and you might
wanna replace any hoses that look almost dead...good luck.


>From: Randberg at aol.com
>Date: Sun, 11 Nov 2001 19:18:38 EST
>Subject: 5000t idle problem
>To: quattro at audifans.com
>[ Picked text/plain from multipart/alternative ]
>    I finally got my '85 5000s turbo started but it runs rough below 2200 rpm.
>It will not stay idling. How do I know if the idle stab vaslve is the
>problem? Randy in MN

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