Hi for the first time to everyone. I just bought my first Camaro, a 1980 Z28 in preaty close to original but nice condition. My question is with my temp gauge. With the car running the gauge stays below 100 no matter how hot it gets, but when I turn off the car the gauges appers to read the right temperature. Does anyone have any idea what may cause this? I was thinking it was a grounding issue maybe?Also there appears to be three diffrent sensors and Im not sure what one feeds my gauge. There is one right behind my waterneck, one in the head on the passenger side near the back and one in the drivers head near the front. Which one feeds the Temp gauge

 

I replaced the sensor today and got the same resaults with the new one. If I ground thewire the gauge goes all the way past the 260 mark so I'm preaty sure the gauge is working, but when connected to the sensor it only shows a temp with the keys in the off position. Come on guys surely someone has encountered this condition before????

 

I have a 74 camaro so I don't know if this is correct for yours. But on mine it's the pink wire (Circuit 39) that goes to the gauge cluster and is responsible for turning on all the instrument panel's functions only when the car's ignition is in the "on" position. I'll see if I can find someting for a 80 z28.

Edit:

Nasty28.com has the wiring diagram for yours. I would recommend buying a wiring diagram book which you can get for about 10 bucks.

wiring diagram from Nastyz28.com

It looks as if yours still follows the same wiring specifications that mine does on some of the circuits (one of which is the plug for the insturment panel to the printed circuit on its back). Circuit 39 is the pink "on" and you should be able to buy a cheap plastic "tap" connector for about 2 bucks at almost anywhere that will allow you to splice the wire without cutting it. I think what you've done is tapped a power wire that's only completing a circuit when the ignition is in the off position and I'm not sure how you did that or how it would only complete the circuit in the off position unless you've got the circuit backwards or shorted.

 

All other gauges work fine only the Temp gauge is screwy. Im not sure if its showing the correct temp with key off or if its just moving to a diffrent position but when its running the gauge shows 100 and dony move from there.

 

Is a stock gauge or an aftermarket?

 

Here's a foldout one for 20 bucks...

You might be able to find it cheaper somewhere else though. My manual's only about six pages but is more than enough. It's helped me through a lot.

 

stock in dash gauge

 

Could be the sending unit. Have you replaced that? On mine the sending unit is between the spark plugs for cylinders 1 and 3. If you've replaced the gauges and it does the same thing then that would be my next step in the troubleshooting.

 

no I replaced the sndig unit not the gauge, I fiured sine when I grounded the wire the gauge needle went all the way up that the gauge was good