Possible Bad Coolant Temp Sensor

[TurboT91]

Hey Everyone,

I have a '91 Talon Tsi AWD 5 speed. I'm thinking my coolant temp sensor might be acting up. Has anyone encountered a Coolant Temp Sensor that wasn't completely bad(throwing a code/check engine light) but giving a false reading. According to my logger, my coolant temps NEVER go over 167 deg. My fans turn on and off and my temp gauge is right below center. I am running a 180 deg. thermostat, a fluidyne rad, and two Spal electric fans with a 50/50 water coolant mix.

My fans turn on at around 164 deg. My O2's are cycling but my fuel trims (aside from O2 trim) always stay at 100%. I'm assuming the car is in warm up mode. It's like the coolant temp sensor is working but giving the ECU false temp readings. Just wanted to know if anyone else has encountered this before I order a new sensor (money is tight).

Thanks

 

[r1991_4g63t]

fill in your profile or tell us whats done to it, dont just say alot. without knowing what mods you have its hard to know what could be the cause

 

[xreaction122]

have you physically checked if the wiring is not loose?
hows your startup when cold or cooled down?
does the startup feel hard or misfire??

that usually means the CTS is bad since it governs the enrichment of the startup

 

[1992awdlaser]

A coolant temp sensor can give false readings without being bad. The reason the fans work is, they are controlled by a seperate sensor that is on the bottom of the radiator.

 

[TurboT91]

All the wiring was redone by me the proper way...soldering/shrink tubing,etc... I'm just going to order up a new one and install it. The car is heavily modified and everything has been done the way it should. I've have actually owned and been working on the car for over ten years. I've just never had a CTS go bad on me...nonetheless not go bad and give false readings. thanks for the insight guys..