Instrument cluster showing higher engine temp

[afterburner]

My instrument panel temperature was not working always, it was constantly going up and down, so I removed the cluster and cleaned the two contacts and now it shows stable and consistent temperatures. The problem is that those readings are around 10 degrees higher then what they should be. I have a 70 degree stat and a fan switch that kicks at around 80 but when the car is stationary the fan kicks in at 90 on the cluster. When stationary the cluster shows 90-95, when cruising the temp drops and stays stable at 80, but it should be 70 because of the stat.

I measured with an IR thermometer and it also confirms that the cluster shows higher temps. How can I confirm that my sender is sending the correct resistance? Does someone know any test values? Thanks!

[UrS4boy]

You are not telling us which engine you are talking about. That said, why are you running such a cold thermostat? Typically Audi's want 87C or 89 C thermostats. Running the engine colder will not be good for engine performance.

The fact that you are getting 80 C when the thermostat is 70C indicates to me that the engine and cooling systems natural equilibrium is higher than 70C and unless you upped the size of the radiator and fan system, you'll never get as low as 70C.

[afterburner]

The engine is a 4 cyl. ACE 2.0 16v that's soon to be turbo.

I am not worried about the performance of the colder engine, because it is not running liquid fuel, so I don't need the evaporation effect from the hot engine.

I measured the actual temperature at the MFTS when the gauge was showing 80 and it was around 70, as my stat. Even if I cut the fuel on a downhill run and leave it in gear + the AC fan on it still stays at 80 on the gauge, meaning that this is the actual stat temperature, so I haven't reached the cooling system's equilibrium, the engine is not generating almost any heat at that point, only that from friction.

[afterburner]

Put my original fan switch in and now the gauge shows around 100 degrees at the point where the fan kicks in, so definitely a problem either in the cluster or in the MFTS.

Does anyone know the test resistances for the MFTS, so I can verify if it reads correctly?

[UrS4boy]

MFTS Info

Put my original fan switch in and now the gauge shows around 100 degrees at the point where the fan kicks in, so definitely a problem either in the cluster or in the MFTS. Does anyone know the test resistances for the MFTS, so I can verify if it reads correctly?

To quote Scott Mockry at the SJM link inside the MFTS link below:

"Unfortunately, the 3 terminal version may fail with a "false" overheat signal which will shut off the A/C compressor and send a signal to the 1991 200TQ 20V ECU to lower the boost. "

This could be your issue.

http://forums.quattroworld.com/s4s6/msgs/22584.phtml

[GazzaG60]

id say so. my 16v q does similar on dash. I think temp switch.