Re: Vacum Leak Causes A Chirping Sound (88 90q)

[Kneale Brownson <knotnook@traverse.com>]

Maybe valve cover gasket leaking?

Kneale Brownson


At 12:54 PM 12/28/1999 -0700, Robinson, Michael/SJC wrote:
>For the past two weeks the "fault light" has come on sporadically.  After
>pulling codes I got Oxygen sensor and OXS Control.  I replaced the OXS and
>knock sensor about 6 months ago, they should be fine.  Greg at M&M Audi Haus
>told me it might be a vacum leak of some sort, causing the OXS control to be
>out of range and causing the fuel mixture to be max rich (my exhaust pipes
>are very black inisde).  I found that the lower ISV hose had a tear in th
>bottom, so i repaced that easily and figure my problem was fixed.  Sure
>enough, the light comes on still, just not as often as before.  After work
>last night I reved the engine and listened for any sound of compressed air
>leaking.  As i would rev the car using the butterfly i heard a quite
>chirping sound, right when i gave it some gas.  I did it many times until i
>pinpointed the sound coming from underneath the intake manifold.  My
>question is, has anyone had any experience like this or know what it may be?
>I really don't feel like pulling off the intake if there isn't a problem
>there.  Could it by the gasket in the intake manifold?  Any help or advice
>would be appreciated.
>
>Mike Robinson
>1988 Audi 90 Quattro
>194,000 miles
>San Jose, CA