Before I run out and get a new cold-start valve...

John Larson westcoast at
Sat Dec 15 11:21:19 PST 2007

This thread has gotten to:

"I'm looking for a sure-fire way to verify that the cold-start valve
> on my 84 4ksq is really shot.  The car does start fine in warmer
> (above about 35F) temps....below that though and it'll take ten
> minutes to start (and my battery/cabling is fine.) I just don't want
> to replace it...and then discover that it's some other
> temperature-sensitive sub-system further up (or down) stream that's
> bad.  Any BTDS's? 

That's the one thing it's most likely *not* to be.

Most likely culprit is the NTC sender on the coolant neck which tells 
the ECU the engine temperature.  It should be a few thousand ohms at 
freezing (remove and put in ice water), and under a hundred ohms near 

Even likelier is the wire from the solenoid to the thermotime switch 
(that NTC sender to which you refer).  They've used CSV/TTS setups since the late 60s on all kinds of EFI cars (and CIS, as well), and the wiring is by far the #1 cause of problems.  On the Audi, the starter wiring hangs down into the dirt/water/road cr*p stream, and the wire either falls off or is deteriorated beyond all usefulness.  Bentley describes the test procedure.  IMO, if any owner of old Audis doesn't own the appropriate book for the car, he/she might as well forget doing anything mechanical or electrical to the car.  John

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