The Q-list comes through again! (Was Re: Weird scary boost fun...)

[Arun Rao <rao@pixar.com>]

> I'll bet you a Fat Tire (beer) that the there is a crack in the vacuum line
> going to the ECU, probably right where  the cloth-covered rubber hose is
> clamped at the intake manifold.   Boost opens the crack, vacuum pulls it shut
> again. The cloth holds it together so its hard to find.

	When I first read Steve's post, and then Alex's success story,
	I made a mental note to check the hose on my '85 5KT, 
	which hadn't registered less than 0.8 bar or more than 1.2 bar 
	for several months.
	
	So .. yesterday, I'm poking around under the hood (as owners
	of old Audi's are wont to do!) and I tug at the aforementioned
	hose. The damn thing came apart in my hands! 10 minutes later,
	I had an engine that was suddenly very happy -- the gauge now
	read 0.4-0.5 bar at idle, and (yee-ha!) 1.5 bar at full-boost.
	No full-throttle hesitation, nice idle. What's more, I'd
	*never* seen 1.5 bar on the gauge before -- the hose was probably
	rotting when I put in the Charlie Smith spring more than two
	years ago.  Moral of the story: if you've got an old Audi, replace
	the cloth-covered vacuum hoses ..

	Sounds too good to be true? Well, it was ... sort of .Went out for
	dinner (en famille) to San Francisco last night, driving somewhat
	spiritedly, gloating all the while to my indulgently smiling wife 
	about my mechanical prowess. Got back, pulled into the garage, and
	got a slight whiff of burnt oil. Pop the hood, nothing's visible,
	engine's running fine.  Quick look under the car -- uh oh -- 10W40
	dribbling from the oil pan mating flange, rapidly forming pool of
	oil under the car. Shut the engine off and went to bed.

	My diagnosis is that the gasket was pretty marginal (I've been seeing
	some oil under the car for a while), and plugging the vacuum leak
	(and driving vollgas!) did it in completely. I've never heard of
	such a thing happening, though.  Any suggestions, folks?


	-Arun

--
Arun Rao
Pixar Animation Studios
Pt. Richmond, CA 94804
(510) 620-3526