First thanks to all that have helped me with my 87 GTA. I located the MAF and replaced it and the K&N filter. I went with a Fram paper filter. Cleaned all the rubber intake parts that hook up to the MAF. Cleared the codes and fired her up. No SES light, man I am jazzed now. The Water Temp Guage quit working quite a while ago. So off to Autozone for the sending unit. The one I pulled does not match the old one. The old has a single round tip with a single wire. The new one has a male/female connection with 2 wires. I read the directions and they state that it is to replace the old round tip single wire.

I carefully solder up add shrink wrap the connections. Yellow wire to the gauge and black wire to ground. Fire it up, and we now have water temp reading. Start driving and the temp shoots up into the red, 260degrees. I shut her down and start checking. The radiator cap not hot, the upper hose is warm, so the thermostat is working, water in the radiator and overflow bottle. Back home. I go. I have and electric Sunpro guage that I was going to use on another vehicle. So I wire it up, use the sensor that came with it. I have two places where I can obtain a switched 12V. Hook it up and no reading. I am thinking possible air in the system. I drive it around and pretty soon the guage comes up and reads 180degrees. I am feeling better now. So I pull up at a light and the guage goes to zero temp…WTF. So I take off again and the guage comes up. I think that somehow the computer shuts off power to the connection I made. When the rpms go up. I try another 12V connection and still the same thing. So I go home and run a direct wire from the battery to the gauge. All seems to be well but the guage never fluctuates. So I bring it home, go thru all my connections and still the same thing. So Now I am figuring the guage is bad. I start it up and now the SES light comes on… WTF again. I clear the codes fire it up and go to Autozone. No SES light They will replace the guage. So off to home to pull it and the SES lights on. Now it seems if I clear the code, start it up drive it SES light, soon as I shut it down and restart it, the SES light comes back on. BY the way its sending a code 36. So now I am totally frustrated, I decide to get some fine brewskis, clean up the tools and the garage and hope you guys can shed some light on my problems I am having. Sorry for being long winded.

 

My 1988, shouldn't be any different. OEM part #8993146
The problem with the replacement is that the engine temp sending unit is a single wire (green,) sensor located on the driver's side head between #1 & #3 spark plugs in the same wire loom as the O2 sensor.

The only sensor with yellow & black wires is the coolant Temperature sensor (CTS) located in front of intake just above the water pump, which is for the ECM, and is in no way connected to the temp gauge.

 

Thanks for the reply, this is a TPI unit if that makes a difference. I may just go and get that part form GM.

 

You say the SES light is coming on, what code is it throwing?

 

Code 36

 

This is what we have for a code 36.


36. Burn off at mass air flow sensor OR
Problem in transmission shift OR
Fault in direct ignition system OR
Missing pulses in electronic spark timing signal

 

Mine is also a TPI, it's available at any part store.

 

I think it should be noted right out loud that there are 2 different temps sensors:

1. A 2 wire (black & yellow) up on the intake manifold that is the Coolant Temp Sensor (CTS) that the ECM uses.

2. A 1-wire (black??) temp sensor screwed into the driver's side cylinder head that runs the gague in the dash.

THat's most likely your parts mix-up. Get the right one and you should be getting more "sane" temp readings.

 

I had already clarified that on my reply of 8-1-2005.