My fuel gauge is not working so I tried some things: -tested my sending unit. No good. - bought and installed a new unit, gauge still reads E - checked continuity on the sending wire, the wire is good. - when I ground out the sending wire, the gauge goes to very full. (confirming continuity) - realized that I have a sending unit ground issue. - when I jumper wire the sender ground tab to a good body ground the gauge reads very full (I have about 10-12 gallons in it) - when I jumper wire to a body ground using this capacitor looking thing the gauge reads empty. Q: what is this thing and do I need it? ‘54 Customline 6volt positive ground.
That does look like a capacitor (used to be called a condenser). They are usually used to reduce electrical "noise". I would start by removing the sender from the tank, connecting the housing to the body with a wire, and connecting the wire that goes to the gauge. Then turn on the key, and move the float arm through it's travel, and see what the gauge does. If it works, then sort out the wiring. If it doesn't work right, let us know what it does.
If an original style tank, capacity is 17 gallons. Should read about 1/2 full with 10-12 gallons. leaving a couple of gallons in reserve when showing empty. I agree with Jim, most likely the capacitor has gone bad. You really don't need it. Ground the sender after adjusting the float arm to read correctly.
I’d swear that this car hates me sometimes. I pulled the new sender out and jumper wired the post terminal to the sending wire. I also jumped a straight ground. When I did, the gauge pegged full. Then “for fun”, I ohm tested the new sender. Nothing. At a loss of what else to do, I used the same jumper wires on the old sender and it worked! The gauge moved with the float. I installed the old sender with a ground straight to body and the gauge reads 2/3. Also, the “capacitor” had no continuity. Thanks for the help guys. I fixed it, I’m not sure how, but it works. Doesn’t seem that hard to test a sender, but I do dumb all the time. Dutch
Capacitors don't show continuity, unless they have a short in them. Pretty hard to test unless you have a DMM that has a capacitor testing function. good to hear you got it working, even if you did waste money on a junk new sender.
STOP and read this! Early Fords, (and I believe the '54 is in the group) use gauges that operate on the "King-Seeley" principle and not on resistance. Almost all "replacement" sending units operate on resistance. Your gauge is most likely incompatible with your sending unit. You need a proper replacement King-Seeley" sender. Hopefully, you haven't thrown the old one away, because it may be able to be repaired. I would suggest that you do a little research on King-Seeley"; it may help. The capacitor is there to suppress radio interference. It mainly affects the "AM" range, so you can remove it if it would make you feel better and don't have the original radio.
Your Ford's gauge is likely a King-Seely (?). They operate differently than the more common resistor gauge and don't respond correctly to an aftermarket variable resistance sender like the one in your picture. @tubman beat me by one click while I was getting the picture I had saved.
Wow! Great info guys. Thanks so much. Somehow, luckily the old one works again (with the capacitor removed). Funny thing is, it’s a factory radio delete car. Thanks again, cheers!
Glad to hear it's fixed. @SillyBabbit please edit the post title to something like "Early Ford Fuel Sending Unit Condenser? (King-Seeley)" Might help the next member who has an issue. Also make it easier to find to reference.
Good you got it going again. Just so you know, the temperature and oil pressure gauges work on the same principle.
My '51 Ford was also a factory radio delete car. It came with suppression condensers on the generator, oil pressure sending gauge, etc.
The Jalopy Journal
