Thank you all in advance. I have an 85 Camaro with a 350 (non - stock), when I first got it the temp gauge didn't function, it went to the top of the gauge when I first turned the key then dropped to zero and stayed there. The last few days it has gone to the top of the gauge and stayed there. It won't come down. I searched a found a post describing looking for a green wire from a firewall harness that leads to the sensor connection on the passenger side head between the first and third cylinder. I do not have a sensor there. Nor do I have any provision for one. However I have two sensors in the water neck at the top of the block. Would one of those be a temp sensor?

 

The one that controls the temp gauge is a sending unit and not a sensor. The temp sensor is for the computer. The gauge sending unit is located on the driver side head in between the # 1 and 3 spark plugs, not on the pass. side head. Just make sure the wire is hooked up to it. If it is and the gauge isnt working, might be a bad sending unit.

 

I don't have anything between the first and third cylinders. No sending unit or anything. I can't find the wire that would hook up to it either.

 

Could likely not have been installed in the replacement 350. The heads may have the provision for one with a threaded plug installed. If not a temp sender can be installed in the water neck or tapped into the manifold.

 

I have what look like two sensors in the water neck already. One has a matching plug in the same harness that has the carb connections for the passenger side of the stock q-jet. The other doesn't have any kind of connector, could that be a temp sensor? If so how would I hook it up to my temp gauge?

 

wait...your looking on the passenger side of the motor?

all 3 of my v8 f-bodies are on the drivers side

 

Don't have one there either. Just an 02 sensor.

 

I dont think your looking in the right place on your head. There is a sensor in the drivers side head in between those cylinders. Its about level with the spark plug holes. Unless some one before you has modifiedthat motor the temp sensor could be any where of 3-4 places. Driver or pass head could have the temp sensor in it. It could be pluged in to the intake manifold. If your seeing a O2 sensor that high on the motor something is wrong there usally at the bottom end of the y pipe. Do yourself a favor and by a shop manual at the auto parts store it has pics and explains alot. it would be a great help to you.

 

It's not the original motor. Temp sensor may or may not be installed in the head.

Look for the single wire lead coming out of the engine harness - not the ECM harness which contains the leads for the carb and the coolant temp sensor (2-wire to ECM) which is normally installed on the water neck. This lead comes out of the harness that crosses the brake booster. If it is loose and grounding it will peg the guage.

Guage sender will be single wire, usually with a spade connector. A PO may have re-installed it on the water neck and may have routed the lead any which way.

 

look for this connector near the steering shaft...its a green wire btw