The gas gauge is not reading the amount of fuel. This happened all of a sudden. Its essentially "off track" in the sense that its just all the way to the right and hanging there. How do I fix this issue?

 

you can go under the car and test the sending unit with a multimeter. the factory sender is 0-90 ohm . if its not reading correctly the sender may have failed.

 

Also check the grounds

 

Turn key on and disconnect the wire from the tank unit, gauge should go past full. Take a test light to ground and check the wire to the tank unit and it should show voltage and the gauge should drop when you touch the light to it or ground the wire. If with the wire to the sending unit disconnected and the key on if the gauge doesn't go past full and there is no voltage at the wire then you have to go to the dash and check.

 

Thank you everyone!

 

I have the same issue in my 84. I can’t seem to find a replacement sending unit. Does anybody have any suggestions?

 

I have a 1984 T/A. my gas gauge is fine but I only have less than 30000 miles on it. Cross my fingers.

 

If I’m doing the sending unit then I might as well do the fuel pump too right ? Also change the gasket. Anyone know the part number for the gasket? Anything else I should do since the tank will be pulled ?

 

Have you truly isolated the problem to the fuel sender? No point in going inside the tank if the problem isn't inside the tank.

Normally, the fuel gauge needle sweeps to Empty when the fuel level sender is at 0 Ohm resistance (a short circuit).
And the fuel gauge needle sweeps to Full when the fuel level sender is at 90 Ohm resistance. Anything more than 90 Ohm circuit resistance will drive the gauge needle higher until it pegs out.

Your needle being pegged high (above Full) means that,
* There probably is power to the gauge with key ON. That's good.
* There is very high resistance somewhere in the sender circuit, likely indicating a bad connection or open wire somewhere. That's not good.

You can do a simple test to figure out whether the problem is inside the car.

1. Climb under the car and unplug the C313 connector located on firewall behind the rear seat (connector with 3 wires). This will make the fuel gauge see an open circuit (very high resistance) and the needle should stay pegged high with key ON.

2. With key ON, jump terminals at the connector on firewall between the center pin and passenger side pin (these should align to the pink and black wires). This will make the gauge see 0 Ohm and the needle should slowly travel to Empty. If it doesn't, then the problem is the gauge or wiring inside your car. If it does, then the problem is somewhere in the harness to fuel tank or inside the fuel tank.

If you want to confirm the tank harness (including fuel level sender) is indeed stuck above 90 Ohm, then use a multimeter to measure circuit resistance in the tank harness between the Pink and Black wires. If it is, then it's probably time to drop the fuel tank to figure out why.

 

good point. I’m not sure if it is or not yet. I was assuming so I bought a new OEM sender ha.
the car is in storage but it’s not stuck on full. The needle is like on empty but like further past empty. Like almost like it’s ‘off’ track in the sense that it’s past the empty

 

Alright, do the same tests I described earlier but keep your eyes open on finding out why the gauge is being pulled low. Make sure the gauge works. If it is working, then there is a short circuit somewhere (resulting in high current in the Pink wire that is pulling the gauge needle toward empty).

Good luck with the investigation. What's most important is you understand how the gauge works so that you can interpret what the test results mean. Just follow the data and go where it is telling you.

 

Have you tried taking the bezel off and seeing if the pointer is merely stuck? You can move the gauge with your finger, turn the key on, and see what happens.

 

I havent yet. I will do that this spring!

 

Will do!
Appreciate the feedback and taking the time to post!

 

I don't know about 1984, but my 1989 Firebird gauge just rests wherever it was before key off. It does not drop to bottom with key off, and therefore cannot get stuck on bottom either. If my gauge pegs low, then something wrong had to have pulled it low first.