Hey guys. Newly registered member even though I've been reading here for awhile. I will detail the complete engine mods made to my 289 this winter later, but while the car was in the shop for the winter I repalced the entire gauge cluster with aftermarket auto meter gauges. The fuel tank is new and empty, the sending unit is new. When the fuel gauge is hooked up it reads full and will only go down when all wires are disconnected. I (we) have tried many things to solve this (old sending unit, several grounds, reversing the hook up etc) without success. Any thoughts?

 

I would say pull the sending unit and properly ground it so you can move the arm and see if you can get the gage to move. If not then I would bench test it and see if you can get any resistance changes when you move the arm. No change would mean a bad sending unit. Also check the auto meter gages again to see if you hav ethe correct one. I think they sell 2 different gages to work with different sending units.

 

Is the fuel gauge for the early Ford sending unit? Autometer offers one for late model Fords and if you use it it will register full when empty. If you have the correct gauge check for a short to ground on the wire from the gauge to the sender.

 

Gauges are from Summit and sales person knew the application. Still could be wrong though. Tried bench testing and moving the float to see if any effect without success. I think I will order a new gauge and sending unit to make sure they are working ok. I can always use the packaging to return one set.