I know that there some of you guys that really understand the 90-92 gauge cluster electronics and I need help....
My '91 Z28 oil pressure gauge has been reading off scale for some time now. Sending unit is good. Dash gauge reads full pressure all the time (the needle is always to the far right - at the point of being off the scale)
This has been a problem since day one. Any suggestions as to where to start.
TIA
-Andrew

 

You probably have the wrong sending unit. Sounds like you have the one for the dummy light instead of the one for the gauge.

 

This is the way the gauge has worked since the car left the dealer's floor! I guess it's possible. If this is the case do you have the part# for the correct sending unit? Thanks
Any other ideas..
-Andrew

 

Disconnect the gauge sender connector (by to the oil filter) and perform these tests:

Does the gauge still read full?

If you ground the tan wire/pin on the disconnected oil pressure sender connector, does the gauge still read full?

Behind the instrument cluster, if you ground the tan wire on the LEFT connector, does the gauge still read full?

That'd tell us where the problem is. If all answers are "yes", then the problem is most likely the gauge (I have a spare one if you need it). Otherwise, it's a wiring problem.

Let us know.
Lou

 

Thanks Lou,
That's some good info
I will let you know.
-Andrew