VCCA Home Forums TECHNICAL - 1945 AND EARLIER 1929-1932 Troubleshooting Gas Guage

I spent some time this afternoon getting the Chevy ready for driving this spring and I noticed a problem with the gasoline guage. When the ignition switch is turned on, the needle on the gas guage is "pegged" in the full position even though I have less than a full tank. When the switch is turned off, the needle goes back to empty.

Any suggestions on where to start looking into problem?? :confused: :confused:
Would appreciate the help.
Thanks

You may have a short circuit to ground in the wire that goes to the tank sender. Do you have a continuity checker or ohm meter?

John and d2d2, that is another reason to show those sixes and buy a roaring four,(1928)to drive!

No wires to the gas gage, however you do have to walk around to the rear of the car to see it.

If your gas gauge reads "full" all the time, then check the wire and the conncetions between the gas tank sending unit and the gauge. Your tank sending unit could be either burned out or you have a bad ground. If you cannot find anything wrong, then remove the wire from the tank sending unit and ground it somewhere near the tank on the frame of the car. Then, turn on the ignition switch and if the gas gauge still shows "full", then you have an open wire between the tank sending unit and the gas gauge. Replace the wire. If the gas gauge shows "empty", then you have a bad sending unit in the gas tank.

Good luck!

I just corrected two different gas gauge problems in as many weeks...

on the roadster delivery, it read "empty" at all times...I disconnected the wire at the sender by removing the wire terminal nut, then grounding it (touching it to a grounded metal part of the truck) as jyd suggests, and the gauge jumped to "full"...

I pulled the sender unit by removing the five mounting screws and found that the corks had shriveled and were no longer bouyant...I reconnected the sender wire, grounded the sender, and while moving the sender manually, the gauge registered all across the scale...

once I get new corks installed, it should work fine...

does anyone know how long these corks generally last?..could these be the original floats?..

the gauge on our kc was stuck on "full"...going through the same process, we found that the sender had rusted in the "up" position...we knew that the tank had a lot of corrosion, as it is constantly plugging the fuel filters we have installed...but a little wd-40 and working it back and forth freed the sender and now it's working well...

epi

I am currently troubleshooting a problem with my gas gauge. If I am reading the information in these posts correctly, if I connect the terminal on the gauge that goes to the gas tank to ground, it should read full?

My gauge reads empty all the time. I tried grounding the terminal labeled tank to ground expecting it to read full, but it remained on emtpy? So I tried another gas gauge that I thought was good, and same results :confused:

Is there a way to confirm the gauge is workng or bad before I drop the gas tank to get at the sending unit?


Thanks,

Jim

Did you have the ignition on when you tried the test? :confused: :confused: :confused:

I would suggest a conductivity test on the meter. A VOM or other test meter should tell if the coils are ok or not. The gauge is a bridge circuit. Also make sure the gauge and sending unit are both grounded.

Hi guys;

I just heard a story yesterday at work were a guy was working on his gas line under a modern car without running down the tank. After removing a line fitting the gas started pouring out and he rolled over on to his droplight. The bulb broke and started a fire. Good thing he was not hurt seriously, but the garage and car had extensive damage.
Be careful! :eek:

Rgwiz
Some 20 years ago the local f*** dealership burnt to the ground because of a very similar incident. In that case noone was injured but not much else was saved. There were 10 customer cars in for servicing and 20 new cars on the showroom floor. So much for safety lead lights.

Thanks for the replies.

I did have the igntion on :) That is something I can see myself doing, but not this time.

I checked the gauge with a meter, and it looks to be good. I did notice yesterday while I was out for test drive that the gauge will move up when I hit a bump. So I tried bouncing the rear of the car in the garage a little and when the backend is bounced the gauge is moving, the more the bounce the more it moves. It may just be the cork is no longer able to float? Can new cork be purchased to replace it?

I guess I'll drop the tank this winter.

Thanks,

Jim

Yes corks can be purchased. The Filling Station has them. I get mine from a local hardware store. The old procedure is to coat them with shellac but I now use gas tank sealer. A thin coat is all that is needed. Be sure that the coateing fully cures before putting it in the tank. I have not tried it but a thin coat of epoxy or polyurethane paint should also work to seal the cork.

Just and update on my initial posting of the problem I had with my gas gauge. The grounding of the sending unit appeared to be the first problem. I had installed an "in-line" fuel filter that interfered with the proper grounding of the circut. I ran a small ground wire from the sending unit dirctly to the frame in an out of the way place so it was not seen...grounding problem solved.
The unit then read empty even when the tank was full. Dropped the tank once more to replace the old corks and now the gauge reads fine.