My '94 944T has started running poorly on cold start. The motor starts normally but revs to 2,000 rpm right off the bat. If it does settle down, it hunts around 750 rpm but sounds like it wants to die.

Cleaned the throttle body and ruled out the TPS, so my attention has turned to the ECT.

As per the FAQ, I'm testing voltage and resistance at the ECU. The ambient temp was 46F (~10C). My voltage was 2.75V which seems right in line with the spec.

The resistance was 1,800-2,000 ohms which would appear to be too low (I would figure around 5k to be the target). But would a lower resistance cause this problem? I would guess the opposite.

Anxious to solve this....

thanks

--
'94 945t; '95 854 base; '05 S80 2.5T

I agree, the effect would be the opposite -- that is, if the resistance were lower than its corresponding temperature, the effect would be to provide less fuel. I think the ECT is not the tree you should be barking at.

(1) The voltage reading is derived from the sensor's resistance, and barring any mess-ups inside the ECU, a 2.75V reading tells you the sensor's resistance is 3440 ohms. The explanation for your 1800-2000 reading is most likely some warmup had taken place between measurements, somewhat likely your ohmmeter isn't accurate, and least likely, the ECU internals (a pair of resistors and 5V regulated supply) are hosed.

(2) The symptoms sound more like an air leak pulling in unmetered air.
--
Art Benstein near Baltimore

Merry Christmas!