I have been plagued with this issue for almost two years now. My temp gauge flat does not read all the time. Somedays it will work properly, but it barely gets above the first hash mark. And I know the motor is not running at 100' all the time. Other days the needle is buried almost pointing straight down and will never raise itself up into the parameters of the temp range. My question is which sensor does the gaues get its signal from. I replaced the sensors on the front of the intake manifold right under the tb, but nothing changed. Help please. I wanna know so I can run an autometer gauge to that sensor and really see whats going on! Thanks fellas

Will

 

Coolant temp sensor is on the passenger side head. Under the plugs. It controls the cooling fans. I believe it is also linked to the dash board guage. There is also a sensor on the drivers head...........

I cant remember what that one is..........

 

Now, I'm not the most knowledgeable on the TPI motors, but the 3 coolant sensors should have the same layout as the TBI motors (someone correct me if I am wrong).

-The CTS (coolant temperature sensor) is located in the front coolant passage of the intake manifold. This is what the computer uses to get coolant temp. info. This is the sensor that you replaced.

-The coolant temperature sending unit is located in the driver's side cylinder head in between the #1 and #3 spark plugs. This is what the gauge in the gauge cluster uses to display coolant temp. This is the one that you will want to use for your Autometer gauge.

-The coolant fan switch is located in the passenger side cylinder head in between the #6 and #8 spark plugs. This is used to turn on the secondary? fan at a predetermined temperature.

 

Bingo!! Ben's right!

 

Then one in the passengers side head works the gauge. The sensor in the back of the drivers side head is the fan switch. There is also a sensor in the front of the intake that reports the engine temp to the ECU.

 

Ben91RS is correct re-read his post

 

[quote]Then one in the passengers side head works the gauge. The sensor in the back of the drivers side head is the fan switch. There is also a sensor in the front of the intake that reports the engine temp to the ECU.]

Ben91rs is correct. The temp gauge in the dash gets its signal from the driver side temp sensor between 1 & 3.

 

the one on the pass side is the fan switch, as Ben has the other 2 correct.
also a lil note of reference for the TPI folks, the IAT and the CTS sensors are EXACTLY THE SAME PART!!!!
found this out when doing some tuning.

 

Thanks alot Ben for the useful info. I will get on that one of these days and replace it along with a few other things I have been meaning to do. Thanks again

Will

 

My camaro is an 88' IROC it's fan switch is on the passenger side head, ECM coolant sensor is on the front of intake, and the engine temperature gauge sensor is on the driver's side head.
Don't use thread sealer, (or Teflon tape) that is not conductive as one-wire sensors use the engine intake/head/block as the ground return to complete the circuit.

 

I usually use a metalic sealer or something like that. I remembr it being conductive. Thanks for the heads up though.

Will