Packard Forum Index » Post-War (1946-54)

Two weeks ago I dropped the tank on my '54 Convertible and installed a new sending unit. The old unit was bad and as a result the gas gauge did not work. I made sure there was no paint under where the sending unit seats and ground paint off the underside of the upper cradle where the tank sits and the top of the tank itself where it meets the cradle. After the install the gas gauge worked fine. The car than sat for two weeks and the gauge did not work. I ran a ground wire with alligator clips at each end from the fuel line where it screws into the tank and a bumper mount bolt and the gauge works. The wiring diagram shows the sender grounding at its interface with the tank. What am I missing?

I doubt you are missing anything. The tank itself was the factory ground and ground was obtained by tank metal touching the body or frame and also thru the connected steel fuel tubing. Rust, new paint or new anti squeak strips all contribute to an intermittent or poor ground. If you have an electric pump and the tubing was cut for that install perhaps the most reliable solid ground path source obtained between the tubing connection to tank and where tubing clamps to the frame was interrupted.

It is harder to add a solid ground on the 51-6 tanks since the sender is not retained by screws but some have managed to solder a wire to the sender retaining ring and ground that to the frame. Others have chosen to drill or punch a small hole in the wide flange around the middle of the tank and use a screw to attach a ground wire. If you have a good section of fuel tubing directly connected to the tank and easy to reach perhaps use a clamp or other means and bond a ground wire between the tubing and frame. You could also use a clamp and bond the wire to the tubing on both sides of the pump to re-establish the solid connection.

My car did come with an electric pump installed. I never considered that the fuel line would/could be the ground. I will try clamping a ground across both ends of the pump before drilling into the flange around the tank. With my luck...........Thanks.