[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Fixed Idle Oscillation

I'm not a list regular, and utilize it primarily when I'm seeking advice for 
a problem with my 88 80Q.  People have been extremely helpful to me on those 

I'd like to provide information on my recent solution of a problem I'd been 
experiencing for a considerable amount of time with an oscillating idle rpm 
and a more recent problem with the engine dying at idle when cold.  I'd been 
informed on list that the former problem was an idiosyncrasy of audis and I 
might as well learn to live with it (or replace the idle stabilization 
controls frequently - expensive).   For the latter problem I suspected faulty 
cold start controls.

It turned out that neither were the culprits.  Both problems were fixed with 
15 minutes work (after many hours of scratching my head) and $23 spent at the 
audi dealership.  The culprit was a badly leaking hose (vacuum?) from the 
idle stabilization control valve to the intake manifold.  There are two hoses 
connecting to the idle stabilization valve.  The bad one was the bottom of 
the two.  It sits on top of very hot engine components and was deteriorated 
very badly from the heat and age. 

The hose is buried beneath the intake manifold, and it looks like you have to 
remove the intake manifold to get to it.  I got an estimate from my local 
repair shop for $100.  While pondering this expense, I picked up the part 
from the dealership and was surprised to see that it was only about 8 inches 
in length and did not require clamps at either ead.  I decided to see if I 
might possibly be able to replace the hose myself without taking off the 
intake manifold.

As it turned out, the air stabilization valve lifts directly off of its mount 
providing just enough room to pry off the old hose.  The old hose pulled off 
of the intake end mount even more easily.  I sprayed the new hose ends with 
silicon to make the blind assembly to the intake end mount as easy as 
possible.  After a few minitues of blindly trying to line up the hose to the 
intake mount, presto it slipped right into place.   You can see the idle 
stabilization valve connection, so that is no problem.  Drop the idle 
stabilization valve back on its mount and the job is done.

Its beautiful when a nagging problem can be solved at minimum expense.  The 
car runs better now than it did 90,000 miles ago when I bought it with 66,00 
miles on it. 

Speaking of that, I would like to replace my 88 80Q with either a 20v Q or a 
'93-'95 90Q.  I'd appreciate any advice on reasons for chosing one over the