The Stovebolt Site Forums The Shop Area Engine Shop Gas Gauge Not Working

I just cleaned my gas tank and put a new sending unit in. I thought this would fix my broken gauage but it didn't. Now when I turn the key switch on, I see the needle move slightly to below the "E"

If I ground the gas tank to the frame, the gauge reads correctly. Sounds like I have a poor ground. Considering the fact that the tank is held down by straps and is full of fuel which is grounded since it contacts the metal fuel lines and carb, etc, I would assume it would be well grounded. However, it doesn't seem to be.

I know I can ground the tank with a wire which will be a quick fix. I would rather determine what is wrong and fix it correctly.

Any ideas?

You need to ground the fuel sender, not the tank. The sender is mounted to a gasket that doesn't conduct electricity. There should be a tab on the sender to connect a wire to that is part of the sender body. Run a wire from that to a clean spot on the frame and you should be in business,
Scott

Neither the original nor the new sending unit had a ground tab. Why don't the screws that hold the sending unit to the tank ground it? The contact the sending unit and the tank so it should be grounded naturally.

I've been dealing with a fuel gauge issue as well. What you need to determine from the start is, is the gauge good. One shot of 12 volts to an original 6 volt gauge will fry it, I bought a voltage reducer for my truck plus a replacement gauge since the original was fried but after inspection of the sender I see that it too needs to be replaced.

Let me know how you make out,
Rick

I could be wrong but, seems like I remember reading in my shop manual that a straight shot of 12 volts will fry a 12 volt gauge quickly as well.
I paid a shop (Hot Rods and Custom Stuff in Escondido, boo hiss! big mistake!) to switch my Pontiac over to 12 volt. When I went to pick it up, the tail lights/brake lights and fuel gauge (among other things) no longer worked. I took it back and they tried to tell me the sender was bad. For 6 years it worked perfectly fine. They do some work and all of sudden my sender goes bad? I wired up an aftermarket gauge and what do you know? It worked. I suspect somewhere along the line they fried my gauge.
No longer do I use the excuse "I don't have enough time to work on it myself".

Everything is 6 volt and I don't believe I have any damaged equipment. Last night I did go out and ground the sending unit. It read 1/2 full. I thought that sounds about right. I filled it up and it reads 3/4 - 7/8 full. Either I have a faulty gauge and/or sending unit. I think my next try is to measure the resistance on the sending unit while the tank is full. If that checks out, I may try adjusting the float.

Did you check to make sure the float doesn't leak?

I believe it is a solid float but I'm not sure. I do know it's new and shouldn't be a problem.