The Stovebolt Site Forums The Shop Area The Electrical Bay 41 Chevy gas gauge problems

Hi I am haveing trouble with the gas gauge on my 41 Chevy, the needle will move between empty and below empty, but won't go any farther even though the tank is full. It's a twelve volt system and the gauge and sending unit are both brand new, can anyone help ?
Thanks,
Ian

Gas gauge problems are usually related to one of two causes; the float isn't working right because it's flooded or soaked with gas or the ground isn't working well.

You say you replaced the sending unit. That should have included the float, so I would look for grounding problems.

One way to test the gauge is to remove it from the tank, ground the flange properly and then move the float arm up and down. The gauge should respond properly. If it does, the problem is likely the ground on the tank. One way to solve the problem is to run a ground wire from one of the flange mounting screws to a good ground on the frame.

If you remove the sender wire from the gauge, it should register full. If you then put a ground on the sender connector at the gauge, it should register empty. When you went to 12 volts, did you do anything for the change in voltage? If you didn't, you may have a burned out gauge.

I replace the gauge and sending unit, both new items are 12 volt

The float that came with the new sending unit had a brass bubble sort of float on it, I will try what you said about the ground wire.
Thanks for your help!

i just hooked up my ampmeter and when i started the engine itwent to the full left discharge so i swaped the wires it went to normal charge rate, so if nothing else works you might have the wires crossed on the gauge.

I'm kinda having the same problem with a '53 GMC. I put a new sending unit in but the gauge reads full (tank is 1/2 full). I tried running a jumper to the unit and grounding the flange like baldeagle said but when I move the float, the gauge needle moves from over full down to full. I wait to hear if you resolved your problem and what you did. Someone told me the sending unit and gauge might be mismatched.

ff171,

Do you have a 6v positive ground electrical system?

Do you have an original sender and original gauge?

I've tried that and it just moved between below empty and empty. The gauge is a new 12v gauge.

Ok I'll look and see if my wires are crossed too, thanks!

Mine is just playing between empty and below empty, I'm gonna try what baldeagle said first then what the others said, I'll let you know what works. Let me know about your gmc! You might figure it out before me!

It's converted to 12v and has a new 12v gauge and new sending unit.

Mine is 12V negative ground and the gauge is a round one bolted on below the dash by the previous owner. The sender is a repo from the classic car parts vendor.

GM up to 1964 - 0-30 Ohms
GM 1965-1997 - 0-90 Ohms

The resistance of the sender should match the resistance of the gauge.

Ok thank you