Greetings,
Does anybody know some troubleshooting short cuts / tips / links / diagrams, etc. to find out why my fuel gauge is reading full all the time. 1989 Firebird with stock tank and sending unit. Any and all information will be greatly appreciated.

Ciao~
BH

 

In general, GM fuel senders measure 0-ohms when the tank is empty and 90-ohms when full.

You can measure this resistance at the fuel tank connector to see if it's the gauge or the sender. Doing it this way requires you to measure the resistance with the tank partially empty.

Or you can perform the test per the attachment (Chevy-Pontiac should be the same for both).

 

Thank you for the information, let me ask you this question:

Before I ask, I have not read the Service Manual PDF's that you posted.

If I remove the connector for the fuel sender and pump (located just above the read diff) should the fuel gauge read empty?

Ok I am bit confused, how does the pink wire get to the dash. Is C208 located behind the back seat and is some how connected to connector C313 which is above the diff? I dont see any wires leaving the tank going to dash.

Thank you for your time.

BH

Thanks
BH

 

Unplug = full
Short to ground = empty

See my signature