Re: Weird scary boost fun...

[Audial@aol.com]

Yesterday I took it out one more time after letting it sit for six hours to
see if it would repeat.  Yes, it did.  Exactly the same way.  In order for
the system to get "stuck", the boost MUST go over 1.1 bar for about 2-3
seconds.  In other words, you have to be driving fairly aggressively to begin
with.  Then the gauge drops back to 0.8 and stays there regardless of
throttle position or engine RPM.  In this mode, the car is very reluctant to
drive at low speeds (heh heh).  The throttle takes on a very "lightswitch"
feel - when there is low load on the engine it feels like it isn't getting
any fuel at all, as if the fuel supply is cut, then when you crack the
throttle it comes on BAM like a clutch is engaging and you can hear the turbo
spool.  If you keep your foot in it you feel like you're tethered to the
Millennium Falcon.  

Now, it seems that the "sticking" is getting worse, because previously it was
returning to normal after about 10 seconds of no-boost operation.  After the
repeat performance yesterday, it stayed stuck for 10 minutes and I had to
shut the motor off and let it sit for about 5 minutes before everything
returned to normal.  During this time the car was nearly impossible to drive
around town because I had to "idle" the engine at 2,500 rpm and then make
what felt like high-boost launches at 3000 rpm in order to keep the car from
stalling. I live in a very populated area and was scaring women and children
with my bronco-bustin' antics.  I'm amazed I didn't get pulled over.  Not the
most civilized way to drive in traffic.  It reminded me of the time the
primary metering jets got partially blocked on my '68 Corvette and I had to
drive about 3 miles home on the mechanical secondaries, meaning approx 3/4
throttle the whole way with a 400hp engine.  Not an easy ride but I made it
in record time.  Now I know why no sane individual tries to drive a
highly-strung race engine on the street - it's exhausting and virtually
impossible not to have an accident or get arrested.

After I first cut the engine, it wouldn't restart immediately, it just
cranked and cranked.  Then I let it cool its heels for a few minutes and
everything was normal again, boost gauge and engine operation.  Niiice Audi,
GOOOOD Audi...I'm going to try to get it to metamorpohose again today to see
if I can dump the fault codes.

I am thinking it might be the pressure sensor in the engine computer box.
 Does anyone know how this thing works and is it replaceable?  Is it
solid-state or diaphragm and how should it work normally?

Thanks,

Alex Kowalski
Demonically Posessed '86 5KCSTQ