The Stovebolt Site Forums The Shop Area The Electrical Bay sending unit

Ok been wrestling with my fuel gauge and sending unit. Was working good at half tank, after fill up goes to empty with both new and old sending units. I can get it to work briefly out of the tank. I can keep it moving after it reads full by turning ignition on and off. As soon as i kill the power to the truck and let it go completely to empty before and after reassembly it stays there. I have jumped wires past the new wiring harness with the same results. I have worked with my ground to see if it good and it appears to be. Tonight I will connect the grounds using the star washers to get a better bite as it seems in all the info i found last night the ground is the biggest culprit. I am assuming my gauge is good as it does work intermittently. Any other ideas? Thanks Steve its on a 1950 3100

Might be a sticky gauge. Or rubbing on the face plate. Just some thoughts.

six volt or 12 volt

The volts shouldn't make any difference Fred. You say you can get it to work "briefly" out of the tank. A bit further info would help. It should show a consistent, continual reading on an ohmmeter as you work the float lever. It should show 0+/- ohms empty and 30+/- full with a smooth transition as you move the float lever. If the reading comes and goes you have a bad sending unit.

its now 12v running through the voltage reducer from classic parts. If I quickly ground the sending unit center post the gauge will go to full as long as the power is on on the truck. as soon as i kill power to the truck and let the gauge go to empty, turn the truck on it stays on empty until i restart the process. I have read that a lot of folks do not even use the voltage reducer, do I really need it or will i fry my gauge? thanks for any input

I can't for certain say you won't fry it but I can tell you that when I converted my 55.1 panel to 12v in the '70s I never even thought about the gas gauge needing reduced voltage. I put over 100K on that truck with the gauge at 12v & it never fried.

took apart the gauge cluster checked the components and all check out good as well as the wiring and sending unit. Only way the gauge works is if i jump the sending unit lead to ground. It will work until the truck is off for a bit then it wont respond until it is jumped again. Aggravated. Any other suggestions would be welcome?

You might have a sending unit with a bad wiper. The part that rubs on the wound wire that is the resister. Try to increase the tension on the wiper and see if it is more stable out of the tank. Hook up every thing and move the float up and slowly watch the gauge and see what happens. In my truck all you need to do is pull the screws that hold the seat back and remove it to gain access. then be careful because you do have an open fuel container right there where you are working. But you can pull the sender and work on it from the seat. Use a jumper to ground it and try it.