Lefty Polaski

The fuel gauge in my 74 reads way past full. I pulled it this weekend and found that if I hook it up to a 9 volt battery it will move but not return to enpty on its own. If I reverse polarity it goes back to empty. Upon reinstallation I had it at empty. As soon as I turned the ignition on it went back to past full. Any ideas of what the problem may be? It is obivously getting current. By the way the tank is less than 1/4 full.

Thanks
Lefty

Pedro'74

Lefty,

If the gauge is reading past full, that means the circuit is open. There are two wires connecting to the fuel sender, at the tank--if either one was somehow disconnected, the gauge would read past full. So the first thing I'd do is make sure the wires are connected. It might be as simple as that--a disconnected wire, or maybe a bad connector. If not, then pull both wires and connect one to the other. If gauge still reads past full, then the problem is the wiring. If the gauge reads zero/empty, then the problem is the sender (and replacing the sender in the '74 is not a big deal).

Hope this helps some...

-Pedro


[Modified by Pedro'74, 3:57 PM 2/17/2002]

Lefty Polaski

Thanks Pedro,
Kind of concerns me because I can only find one wire running from the sender and no other wire or connection in evidance. Hummmm.... I'll have to dig deeper and see where that other wire went.
Thanks again
Lefty

Pedro'74

Lefty,

Guess you've found the problem already.... If I remember correctly, one of the wires is black and is hooked up to a flat type terminal. The other wire has a rubber boot, and hooks up to a kinda "plug"-like terminal.

-Pedro

Lefty Polaski

Hi Pedro,
I found it!! When the rear bumper was replaced someone bundled the wire with the rubber boot with the wires for tail lights. Plugged it in and the gauge went from past full to empty. That's promising as the tank is nearly empty. We'll see what happens when I put gas in it in the spring. I've got it up on jackstands for the winter while I redo the interior and do some work under the car.
Thanks Again
Lefty

Paul Borowski

Lefty, one other thing to keep in mind is your black wire for grounding the fuel sending unit, license plate lights and taillights. It is near the rear of the frame just above the left muffler. If this ground fails to work properly, your gauge will do also what you said your's did in addition your taillights may be real dim or not work at all. Happened on my '68(fuel gauge went way past "full") this past summer and this was the problem.