I am a new member here on this forum and I have a 83 Z28 with the crossfire injection and is totally stock inside and out. it has 135,000 miles and no major problems yet not even smoke. My temp gauge I believe just died on me how would I fix this? Do I need a whole new gauge or do I just need some type of sensor. I did replace the coolant sensor. any help would be great. I cannot stand gauges not working.

 

J&J,

Welcome Aboard!

There are at least two coolant temperatire sensors on your engine, possibly three if you have electric radiator fans.

There should be one sensor in the front coolant crossover of the intake manifold. It should have a large white connector with a single wire or smaller connector with two wires, (probably yellow and black). That is for the ECM and engine control input.

There should be another on the left (driver side) cylinder head. This sensor should have only a single wire (probably light green) in the connector, and is the sensor used to signal the dash gauge.

There may possibly be a third sensor on your car in the right (passenger side) cylinder head, which would be for operating the electric cooling fan(s) behind your radiator.

If you didn't replace the sensor for the gauge, it may explain your problem. You can test the sensor wiring and gauge operation in two ways.

First, whenever you crank the engine, the temperature gauge should climb rapidly toward the "hot" end of the scale, then return to the correct reading as soon as the key is released. If this doesn't occur, you may have a problem with the gauge itself. If this is still working, the gauge itself is working, and you have a different problem.

Second, you can remove the connector from the sensor in the left cylinder head, ground the wire to a good engine ground, then turn on the ingition. The temperature gauge should climb to the full "hot" end of the scale. Removing the wire from ground should return the gauge to the "cold" end of the scale. Grounding the wire again should cause the dash gauge to go full scale again. If this doesn't work, you have a connection problem between the sensor and dash. If it does work, the likely cause is the sending unit.

When you replace the sending unit, use only a thin layer of teflon pipe sealant. Too much sealant and/or inadequate torque of the sensor can result in a poor ground path for the sensor body, and no gauge operation. The sensor body must be grounded to complete the gauge circuit.

Good luck - keep us posted.

 

Vader thank you for the info. installed both sensors though no movement. The gauge is pointed past the hot and just stays there. could the gauge itself do this and if so where could I buy a new one.
Also my speedometer cable keeps breaking almost every 2000 miles. Though when it works the needle shakes, what would do this. any help Thank you