UR-Q WARMUP FIXED (uh, sorta)

[Bryan Gunn <bgunn@voicetek.com>]

Hi folks,

As you may or may not know, I have been wrestling with a warmup problem with
my ur-quattro. Now, after many months, many temperature senders, and about
a mile of new vacuum line, I've almost got it licked.

One of the things that makes Audis, and ur-quattros in particular, such a pain
in the neck is that Audi dealers don't know how to fix them when they break.
I guess this frustrates them to the point of doing stupid things. Check this
out:

Since quattro is short on instruments, there is a 3x4 grid of idiot lights 
on the dash. When the engine is too cold or too hot or doesn't have oil
pressure or whatever, it turns on one of the idiot lights. The blue "cold
engine" light is supposed to come on when the coolant temp is low, meaning
the engine is not warmed up so take it easy. Well, my cold engine light wasn't
coming on, and the engine would always run rough when it was warming up. Hmm.
Well it doesn't take a genius to figure that there's a temp sender somewhere
that's crapped out. So I replaced the thermo-time switch, and the head mounted
temp sender (the one in the back of the head), and the 3 wire sender in the
bottom of the radiator (as an aside, can anyone know what the 1 wire temp
sender thingy on the right side of the cylinder head toward the front is for?
And when I say right I mean if you are standing at the front bumper looking
at the engine.). Okay. So new temp senders.

These temp senders made no difference in the car's warmup, but they did cause
the "fasten seat belt" idiot light to glow once the car warmed up. Yippee.

At this point I got out the mity-vac and found a couple vacuum leaks since I
was sick of dealing with electrical problems. I highly recommend getting a
mity-vac. They rule. You can locate vacuum leaks lickety-split. So I got rid
of all my vacuum leaks. There were only a couple small ones and didn't really
affect the way the car ran.

Back to the electrics. I started cleaning grounds. I cleaned all the grounds 
I could find in the engine compartment. Started the car and LO AND BEHOLD IT
IDLED RIGHT ON THE MONEY RIGHT THROUGH WARMUP!!!! But the blue cold engine
light still didn't come on and the seat belt light did (after it warmed up).
So there must still be a bad ground somewhere. Fine. But maybe the clod
engine light bulb in the dash is burnt out. Off comes the steering wheel and
instrument cluster. Here's where it gets good. The "cold engine" light was
plugged into the "fasten seat belt" socket. And the seat belt light was in the
"cold engine" socket. And the "check engine" light was gone altogether. I
guess some exasparated serviceperson couldn't make it go out by fixing 
the car, so he or she simply removed the offending light bulb. I replaced the
"check engine" bulb with the oxygen sensor bulb (I just put in a new ox sensor)
and fortunately it did NOT come on (a testament to the mega bucks I've sunk
into this thing).

So now the only remnants of my warmup problem are: No "cold engine" light when 
the car is cold. "Cold engine" light when the car is warm. A slight drop in 
idle when the car is in that "lukewarm" state (like a 50-100 rpm drop - not
enough to make the engine stall or even come close, but enough to notice).

So my strategy is to clean the rest of the grounds (there's at least 10). Then
if that doesn't work, to replace the little 1 wire temp sender toward the 
front of the head (the one I mentioned earlier).

Anybody have any ideas as to other things to check?

PS. While I was visiting my folks for the holidays, I went to a junkyard and
scored the exhaust manifold and brake calipers from an '88 5000cstq. If memory
serves, this should be the famed 2-piece manifold (they're pulling it and 
shipping it to me this week). And the brakes should be famed dual piston
calipers (again, they're pulling the parts). I got the complete manifold for 
$150, and paid $50 each for the calipers. Good deals, I hope.

Later, and thanks for reading this far.

-- 
Bryan Gunn                  Email: bgunn@voicetek.com 
Voicetek Corporation          Tel: 508.250.7998
19 Alpha Road                 Fax: 508.250.9378
Chelmsford, MA  01824