Re: UR-Q WARMUP FIXED (uh, sorta)

[rdh@sli.com (Robert D. Houk)]

   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
   ...
   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

That's the one that turns on the Blue Light (cold engine), I think.

   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

That's the radiator fan switch

   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.

That is *THE* temp sender (by "THE" I mean the one the ECU listens to, and
decides how to control the engine; all the others are just fluff to con-
fuse the innocent and attempt to compete with other foreign car makes in
seeing how many gizmos they can graft onto the engine without breaking it).

   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.

Hahahahahahahahahaha . . . 

   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

Sigh. 

   "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).

The "O2 sensor" light is triggered by a odometer-driven switch, and has
nothing to do with actually verifying that the O2 sensor is even present,
let alone working right.

   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).

Put a duty-cycle on the FreqValve test point (you do have the de rigeur
SunPro CP7678 (or whatever), don't you? Why not?) and see if that is where
the duty cycle suddenly plummets from 5x% to 41% then back up to 50% just
before going closed-loop . . .

   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).

Probably not busted . . .

   Anybody have any ideas as to other things to check?

Um, your sanity? (I gave up on mine a long time ago!)

					-RDH