My 31 Independence fuel gauge only reads 1/4 no matter the fill. At turn of key it goes from E and flips up immediately. Wiring to the tank appears to be in good shape.Tank looks new so assume the float had been replaced at the same time. Attempted to check but it appears it will be necessary to drop it to gain access. It's full to the brim currently but still reads only a quarter on the meter.
Just Google “Troubleshoot Fuel Gauge”. There are lots of great YouTubes to help you determine if the problem is the gauge, the wiring, or the unit in the tank.
If the vehicle has been sitting a while it could be that the float arm is stuck either due to gum/varnish from evaporated gasoline or rust.
Until you do some troubleshooting everything we post is just guessing.
To really understand what is going on with that system you will need an ohmmeter.
It had set in the same spot for eleven years with little gas in the tank. Very possible the float is stuck. What if I attempted to free it up utilizing a coat hangar through the filler hole? Either that or a cleaner additive in the tank?
Please do the proper troubleshooting before you attempt any repairs. You could ruin a perfectly good sending unit. Or break off the float so you are then forced to remove the tank to get out the pieces.
Crawled under the car earlier today and the tank is flush mounted to the frame thus impossible to trouble-shoot at that end without draining the unit and taking it off the car. No ready access to the sending unit and float.
Thanks Rusty. I've owned several 50's cars all with bad gas sending units. All were easy access via the trunk floor. Amazed this Chevy requires a drop of the tank to access if the sending unit goes awry.
If you do not have a nice warm shop with a lift, the cheap and easy method would be to use a paint stirring stick. Once the weather improves you could make it a weekend project. In our '40 the gauge does not work so we just keep a mileage log in the jockey box. It got a predictable 15 mpg. It was in the process of being hot rodded when we got it. The tank had already been replaced, they may have installed a 12 volt sending unit in a 6 volt car. Someday I will investigate and make it a project.
Thanks for the assist. What's strange is all articles indicate issues with gauges that consistently show Full or Empty. Mine is stuck at a 1/4 setting. It registers empty until I turn the key. Then jumps up to the 1/4 mark and stays there no matter what the true tank fill level.
What were the results when you tested the circuit following the steps in the Filling Station article?
Will the gauge go to full reading when you disconnect the wire at the sending unit? Will the gauge read empty when you ground the wire?
Until you test the circuit electrically you do not know if the problem is the gauge, the wiring, or the sending unit.
I have had issues with old gauges being so dirty that they would not travel full range. Also, there could be corrosion with where the gauge mounts to the dash.
Please post again after you have done the testing.
In looking at a few tanks, catalog, and senders it looks like you could have a couple of different tanks and senders. I agree with the above comments about dropping the tank once you know it is necessary. It wasn't to hard but run it dry or drain it as much as you can. The tank with the single float has the sender about 12 inches from the end of the tank with the fill hole so it is conceivable you might be able to get the sender to move with something but I don't think it will free it up enough to be useful. If it is the double float there are gears and shafts that most certainly are rusted and will require careful repair. The senders are not interchangeable and the repos may not match your hole pattern.
Dave - The car was restored twelve years ago and then parked for eleven years due to the owners demise. The tank looks newer so assuming it had been replaced at the time. My guess is the float has stuck in place and will need be either freed up or replaced. As luck would have it just filled the tank to the top and being winter not likely to drive the car until spring. Agree it need be dropped and need take a look inside.
Took another look at the tank this morning and it's obvious it and the wire leading to the dash gauge had been updated with the restoration. Cannot access the float to check for ground or function without dropping the tank. Suspect the gauge since it appears old and crusty. Where it fits against the dash is clean and tight so it doesn't appear to be ground related on that end. Is there a way for me to clean or repair the gauge? Either that or suggest a shop that can refresh it?
If you’re under the dash, disconnect the wire coming from the sender, (with ignition on, test the wires for voltage, the one with voltage do not disconnect, remove the other.) Turn on the ignition again and if your gauge is good, it should read full. If it does, run a wire from the sender terminal to a full chassis ground. With ignition on it should show complete empty. If all this checks out, it sounds like it is the sender. There’s a good chance the new ethanol gas ate away the cork float and the small brass float arm isn’t moving due to the gears on the sender gummed up with green crud. Sometimes the contact inside sender has too much spring pressure on the contact that runs along the rheostat and it won’t move because the float is gone. I’ve seen over ten tanks that I recently worked on virthave nothing left to the cork floats and have a stuck sender arm. To replace the float go to Aircraft Spruce and order their replacement floats for home built aircraft. Way cheaper than buying floats from antique car parts suppliers and aircraft parts have to work as there’s more stringent requirements.
It's the sender unfortunately. Only because I need drop the gas tank to get at it. Ran the tests suggested and the gauge, power draw and wires appears to be just fine. The tank has a drain on the bottom so need run most out and perch the rest. Appreciate everyone's assist. Thank You!
Be careful with the drain, the threaded part is soldered to the tank and many times trying to loosen the plug will break the solder free. Use a siphon or a drill powered pump and empty the tank that way. I never touch the drain plugs.
dropping the tank is not that bad. done it more than once. 2 straps, 1 fuel line, wire for sender. easier when rear is up on lift or jack stands.
when i put a new sending unit in the 1930 i followed Ted's (Chistech) advice and ran a ground wire from the sending unit to the frame to back up the ground it gets from screwing to the tank. this was cheap insurance to ensure a good solid ground !!
and while you have it out, have it cleaned, my local radiator shop dips them. then i repaint the outside and looks like new. they will also coat hte inside with an industrial coating if desired. they do a ton of radiators, heat exchangers, etc... mainly for the military around here us car guys get the perks of an old school shop that knows what they are doing and very good at it.
AACA - VCCA - Stovebolt - ChevyTalk Love the Antique Chevrolet's from 1928-1932 The Beauty, Simplicity, History, and the Stories they Tell
Really appreciate the warning about the drain. Also the ground wire advice. The exterior of it currently looks newer but it could be an old unit painted to look nice. Will due diligence to assure it's put back on with any issues addressed.
