samkin said:
Hi guy. Im restoring my old 77 k10. I replaced the gas tank years ago when i bought the truck. The gas gauge wasnt working at the time. I found the ground wire was broken so i fixed that when i changed out the tank. The problem is when the fuel gets down to about 3/4 to 1/2 the gauge starts bouncing all over the place as the truck is moving. Any thoughts. I would like to fix it while i have the cab off the frame. Thanks for any help.... Sam
Most often the problem is in the wiring, especially the ground. Since you've fixed that (and verified it), check the supply current wiring and connections.
On the sender, check the wire that is wrapped around the core of the rheostat for being loose. If it's loose, when the wiper that's connected to the float gets to the loose part of the wires, they can move and short to each other, changing the resistance- and causing the gauge to wander or bounce.
Also you can look the wiper over closely (and the entire assembly for that matter) to be sure there's nothing on it that's contacting the rheostat at the point where the needle fluctuates causing a problem.