67' Fuel Sending Unit, No Ground?

Hello all, another dumb question. The fuel sending unit on the 6-gallon cell under the seat has only one wire(sending). Is there supposed to be a ground attachment somewhere, or does it just not need one? There is no other hook-up I can see, unless you just use any one of the mounting bolts. Thanks for all the help. Got that 225 running pretty good now.
(67' CJ5)

 

The metal tank is the ground.

 

But not a good one.. So just put a ground wire onto one of the screws on the sender cover and take it to frame.

 

Will do! Thanks!

 

i kinda have the same problem. i have the ground attached to one of the mounting screws on the sending unit, but when i turn the key, the gas gauge just barely moves off the E peg. even with a full tank of gas.
any ideas??

 

Remove the wire (hot from gauge) to the sender and temporarily touch it to the ground wire. This will make the gauge go to full. If it does, then you have a bad sender. If it doesn't then check for better ground, or bad wires, or bad gauge. You may have lost the float off the sender control arm?

 

My fuel gauge just stopped working one day. And after getting tired of checking my fuel level with my lighter... No not really, but I took it apart and found that the brass float had a pin hole in it. Thus always reading empty. I made a cork float for mine and attached to the arm and it is working fine now.