On my 89 rs the temp gauge shows over 260 degrees even when it is shut off , so I replaced the temperature sending unit. What do I look at next? Not sure if this helps but the oil gauge isnt working with. Not sure if they are related.

 

Short in the wire, or bad instrument ground to gauges?

 

First post/reply ever here, so give me a break if this is the wrong format. Trying to learn.
With my experience on my '87, the ecu decodes the signal from the sensors on the engine, and then sends them to your cluster. If your engine stills runs/starts well, your ecu is most likely reading the temp correctly, but the signal is not being received on your gauge cluster.

 

No input from the ECM on these cars. The gauge system is exactly the same as a 55 Chevy.

The problem here is either a bad sending unit, bad wiring, or the gauge movement physically stuck. Or even, the GAGES fuse (yes it's misspelled on the fuse block) is blown.

Could be the wire shorted to ground but that would be unlikely anywhere except where it connects to the sending unit.

If the oil pressure gauge is also not working I'd check the fuse first.

 

ive been on vacation so now that I have time to get back to this I will check the gages and see if it is blown. Would the gages control the tach and charging gauges? They are both working.

 

Yes it does, so if those work, then the fuse is good.

 

next step will be chasing grounds.

 

I was just thinking about this, but does the temperature sending unit control the electric fans?

 

No. Not the one for the gauge, that is. The gauge circuit exactly is the same as it has been since the 50s. Even the same color wire and the same connectors.

Probably not a ground issue. All the gauges are bolted into the metal pod. If one is grounded, they all are.

 

I just had to replace the gauge in my cluster. Everything wire wise was fine.

No matter what with the old gauge it would stay pegged past hot.

I got a new gauge and once I plugged it in it immediately dropped to the bottom. I grounded the green wire with key on and it pegged hot as it should.

 

Yup, even as simple as they are, the gauge itself can in fact go bad. Sometimes it's as simple as something just getting hung up when it goes to the extreme of its range, and can't get itself unstuck. Like, just tweeeeking the pointer with your finger might be enough to repair it.

Glad you got yours sorted out, in any case..

 

where did you get a new guage?

 

You can order a new one from Classic Industries: https://www.classicindustries.com/pr...b225fca5dc2eca

I tried to chase down my temperature as I felt the engine was running a bit too cold, here is where the temperature gauge sender is and what I replaced: https://www.thirdgen.org/forums/nort...ml#post6422334

I may buy one too, but since the gauge is consistent at what it reads just below 160*, never hits 160*F before fans kick on (I have a Hypertech Power Chip Stage II which is set for 160*) I’m comfortable with the gauge I have so…

 

Found a guy near me selling used Camaro parts and happen to had one in an old cluster.

 

I heard sometimes the camaro gauge can get stuck.... if you're going to go try replace it might as well open it up and tap it with your finger to see if it gets unstuckk?