Autometer fuel guage not working

autometer number 4315, 73 OHMS empty/ 8-12 ohms full, for most fords before 1989 and most chrysler vehicles.

thats right of the box.

I do have it wired so that it is 12 V, i checked the power into the guage and it is 11.8 V with the car off.

Still about 4 V on the wire to the sending unit at the guage and sending unit.

I ran a jumper wire from the fuel line to the rear to double check the ground, but I still have 4 V at the rear, and OL displayed when i switch the meter to OHMS.

There is probably only 3 gallons in the tank, so the reading should be low, but i have no idea what the voltage is supposed to be.

Thanks,

Steve