The Stovebolt Site Forums The Shop Area The Electrical Bay Gas Gauge Question

Members, I installed a new gas gauge and sending units in my 54 3100. I tested both before installing...seperatly and then together. All was fine. I installed them and they worked fine for 600 miles. Now my gas gauge is pegged at full. When I turn the motor off the needle is at 1/2 way...turn on and it pegs.

Befoe I start tearing into it..anyone else have this problem ? could save me a bunch of time.
I plan on checking my grounds,then taking out sending unit,and checking it manually. Having it hooked up and moving the float arm up and down to see if any movement...then go from there. Is this the right direction?
Thanks

6v or 12v electrical system?

6v or 12v gauge?

If 12 electrical system and 6v gauge, what type of resistor, and how/where is it connected?

More than likely you've lost the ground at your tank that the sender needs to complete the circuit. Does it have a short ground wire at the sender flange or was it getting it's ground through the mechanical connection of the tank to the body? You may have to add a ground wire. You can easily test to see if this is the problem by adding a short ground wire from the sender flange to a good chassis ground.

If all that looks good, check each connection and splice (if any) between the guage and the sender - something has become discombobulated!

Jimmi -

I'm in the middle of replacing the fuel gauge on my '54. Hope it lasts longer than yours. You may have also lost the ground between the back of the gauge and the inside of the gauge cluster housing. Should be sanded shiney bright.

>> Question: When the ign is off, does (did) your fuel gauge read EMPTY or did the needle settle somewhere near the middle. The gauge that I bought from the Truck Shop settles a little past 1/2 full in the box before hookup and when hooked up with the power off.

Good luck with your gauge.

The loss of ground at the sender or loss of connection between gauge and sender would spike a good gauge to Full.

What about the 50% reading when off? Did it originally read completely Empty when the key was off?

Tim -

Not sure about the EMPTY reading with a bad ground on the gauge. That ground serves a different purpose than the ground at the sending unit. I bench tested my gauge and forgot to ground the gauge. I remember that it didn't read right when I briefly connected to power, just don't remember what it read. (Senior moment). Not saying you're right or wrong. Just saying that I'm not sure.

RE: my "50%" reading - -
My fuel gauge is a repro. It read 50% in the box. I bench tested it with the repro sending unit -- sending unit and gauge properly grounded. Seems to work OK, just does not go back to EMPTY when off, like the original ones did. I called The Truck Shop and was told mid-reading when off is OK. I noticed that pics in the Truck Shop catalog and other suppliers show the needle at various locations other than EMPTY.

Jimmi - please update us when you find the problem.

Hey Guys, 12 volts system. My gauges were tested before putting them in. BUT....I had painted the housing inside and out ( to make it pretty )...gauges didn't work....had to investigate about the ground. Took it all apart ground it down and reinstalled it...worked great. I even gounded the sender with a wire to the back of the cab.
I just got back home,so I haven't had a chance to check it out. Still confused about it only going to half when Ign. is off vs. empty reading...Unless it reads what is in the tank even when off?
I'll keep you posted.

Thanks

Like I said, my 12v repro gauge from The Truck Stop reads about half full when off. It was that way in the box, before I hooked it up. Maybe that's the way gas gauges read in China!

and you didn't immediately ask for a refund??

Bill

The reason I backed off asking for a refund is that on-line photos of 1954 12v fuel gauges at American Classic, Classic Chevy, Filling Station, and The Truck Shop were all at 1/2 full. Jim Carter pre '54 gauge pics were also 1/2 full - '54 NA. Only Chevs of the 40's showed gauge at Empty, and that was available only in a cluster. Maybe it's a 12-volt thing (?)