The Stovebolt Site Forums The Shop Area The Electrical Bay 54 fuel gauge saga update

Well...finally got fuel gauge to work but backwards...have completed every test on this site that has been addressed. In the last trial i took everything out of truck..gauge and sender...worked fine. I put the gauge cluster back in truck and manually moved sender up and down and it worked!! Put sender back in tank and read half full which was correct. After patting myself on the back I turned the key off and gauge went to full!!!! Turned key off and the gauge never moved. Pulled sender back out. Key on, all worked fine...sender back in tank ...read half full...turned key off and gauge moved to full and won’t come back. Tank is grounded, cluster is grounded, gauge is grounded.. can remove sending wire with key on and gauge will show past full as it should..put wire back on and it goes to full and stays there whether key on or off...checked the key switch and all good. As stated several times before ...will work fine on bench test but not in truck. I’m giving up and going to start work on my bed wood...if anyone can think of anything I might try or tast let me know...time for Super Bowl ! Go Chiefs!

When you have the sender out (and the gauge mounted in the dash), it works correctly? That is when the float is at the bottom the needle registers empty and when the float is at the top the gauge registers full?

Green: How was sender grounded during this out of tank test? I see you said you grounded sender to neg batt post. Was that wire to the sender flange metal?

Red: It's not the tank that needs grounded, it's the SENDER! that needs grounded from one of it's mounting screws. You say you put gauge back in truck and you kept sender out and Moved it up and down and it worked. During that test sender was grounded to battery negative. Then you installed sender and it does not work. That means sender is not grounded to the frame of truck. You need a wire from sender flange screw to frame of truck. Grounding the tank will not do it.

The sender has a gasket, the tank has cushions, the straps can have rubber under them. So all of it is isolated from ground mostly and the sender's ground gets lost and is relying on it's screw threads. Put a wire under one the screw heads and other end of wire to a good ground bolt on frame. Clean metal both places, no rust, no dirt, no paint at those points.

I don't know what you meant when you said you found a glass/bezel problem. Sounds fishy, what was wrong? are you sure you fixed that?

Gauge should have sender wire on the full side terminal and the power to the empty side terminal.

cab ground strap maybe?

Yes, Ed: T and M have made a good point. The ground must be good between battery and body/motor/frame/dash. in any order. Double check that path. orrrrrrrrrrrrrr....run a temporary ground wire from battery neg to the sender flange/screw AFTER sender is installed into tank.

Thanks for reply...I will try to make more clear....the sending unit itself is grounded to the negative side of the battery. I was using one of the screws but now have it clamped to the gas pick up tube and continuity test shows it is grounded. In regards to the gauge cluster ...it is also grounded by a wire I attached to it and runs to negative bat terminal as well as the three screws that hold it in dash. The switch is wired to the empty side of gauge and the sending unit wire is attached to the full side. When I took the sending unit out of the tank it remained hooked up the same way. Out of the tank and moving the float up the gauge went to full...float down it went to empty. Did this 4 or 5 times. (Key on) .. I put sending unit back in tank..turned key on and gauge read half full which was correct. After taking the cluster out so many times and the gauge out seeking better ground I finally managed to fry the gauge so a new one has been ordered. I will move sending unit wire to frame...I guess I assumed neg battery post would work. I forgot to add the gauge would not go back to empty with key off

Negative battery post would work. Are you talking having a permanent wire from battery neg to sender? Would be odd, but sure would work and be better.

Yes I did have a permanent wire to negative post but now have it grounded to frame as many have suggested..the battery is under the floor board so using the negative post was not a big issue. Waiting on new gauge ...if I can’t get this one to work I guess I will find me a good willow branch to put down in tank like my dad use to!

New gauge came in today and I got it installed...I can only relate my experience with the 12V gauge for the 54 ...none of the 3 I have used will return to empty with the key off...in fact they all came out of the box with the needle on half tank or more. It will register the 3/4 tank of gas that is presently in the truck with key on but goes back to full with key off. I don’t have a clue why it works this way but guess it doesn’t matter as long as it reads correctly with key on....time will tell on that matter. Thanks for all your suggestions ...can always depend on good advice on this site. PS ...if I ever do this again I think I will use the 6V gauge with a resistor.