superman3301

Hi all, my gas gauge in my 69 Charger is not working and I've tried a couple different things.. First thing I did was replace the fuel sending unit as I was restoring the car. I have one wire hooked up to the sending unit that goes back to the gauge.. There are times that the gauge just takes off and goes all the way past Full and stays there. Any ideas on what I can do to get the gauge to work? I'm not sure if something needs to be grounded on the tank or sending unit or not?? Any help or ideas would be great. Thanks

440roadrunner

What other gauges do you have, IE do you have the rally dash with an oil gauge?

Does the temp and oil (if you have it) seem normal?

In general, the cluster is fed "ignition run" (dark blue) or IGN1 from the ign switch. This goes to the instrument voltage limiter, and then branches off to each gauge

The gauges must be making good contact in the PC board, so check the connections there.

From there the (fuel) sender wire goes down to the harness connector for the rear harness down in the left kick panel, then back to the rear.

Yes the tank sender must be grounded. Originally a special clip hooked to the sender tube, jumpered over the top of the rubber connector hose, and clipped to the fuel tube.

You can clamp a wire pigtail to the sender tube and ground it to the body

superman3301

Awesome. Thank you so much. I'll go out there and dink around with it to see if it'll work. I do have the oil and temp gauge. They seem to be working fine. I didn't know about the ground wire so that is where I'm headed first. Thanks for the detailed reply!!

fivepoint

If it is pegging out past full, make sure that the wire going back to the sending unit is not grounded somewhere. If you disconnect the wire at the sending unit and the gauge still goes toward full with the key on, I would say that wire is grounded somewhere between the gauge and the sendng unit. On my satellite the wire is in the trunk and passes through a grommet in the trunk floor. I always thought that was a bad place to route a wire.

superman3301

Yeah mine goes through the trunk floor right through the rubber grommet.. It does peg out so it must be grounding out somewhere. I'll def check that tomorrow morning too. Thank you very much

Garys69RR

I just went thru all this on my 69 Road Runner. A good place to start is to have some one sit in the car, and with the key in run position, remove the wire from the sending unit lug on the tank, and ground the sending unit wire momentarily. Make sure you have a good ground connection. The gauge should move fairly quickly towards the full mark on the gauge as soon as you ground the wire. Then when you remove the wire from ground, it will move back towards empty more slowly. See if that test works or not. Good luck.

superman3301

sounds like a good plan. Thank ya sir