Hi all, looking for some expertise.
Gas gauge needle is pegged at top above full. After reading some other posts, tried disconnecting sender wire in trunk with power on at ignition. No change, needle still at top. Took car to speedo shop, hooked up potentiometer to sending wire in trunk and tested it up and down, no change. Removed instrument cluster and had them bench test it. Gauge works. Haven't tested wire for continuity yet, just trying to figure out how this would suddenly fail when wiring hasn't been touched? If anyone is familiar with these, I'd appreciate some suggestions on what else to check.

Thanks,

John

 

You have a bad connection between the sending unit and the gauge. The gauge has a constant 12v to it and the sending unit in the tank is the ground side. If you remove the wire from the tank and ground it, should read empty. If it does then it's the sending unit in the tank. If it does not then run a temporary jumper between the tank and the gauge.

 

Performed test as you described, and gauge went to Empty. Thanks for the input, so glad issue isn't with wire in main body harness! I'll prepare for fun removing sending unit...

Best, John

 

It's not bad to remove, just drive your car until the tank is almost empty.

 

Your biggest issue will be finding another one if the one in your car can't be repaired. After 50 years, the problem is more likely one of corrosion and/or wear, and repair might not be possible.

These things are not made new in the aftermarket, as I found out trying to find one for my '67 Delta. I ultimately found that a sending unit for a '72 Delta would work even though the mechanism was different, and, fortunately, and for the moment, those are still made. But it fit.

You may have to do something similar. Find a unit for a comparable Chevy or something that is made in the aftermarket and that will fit and work. It may require some hunting and contacting places specializing in vintage gas tank and fuel system parts.

Also, unless your tank is nearly empty, anyway, rather than waiting until you've driven enough to lower the level, which might take a while depending on how often and how far you drive the car, you can also just siphon the gas out. That's what I did. You can buy a low-cost siphon pump and tubing that will work at the local auto parts store.

I didn't have a 20-gallon container to siphon into, so I just siphoned into a regular 5 gallon gas can, and as it filled, I would stop and pour the gas into the tanks of my other cars so that I didn't have to store it anywhere, and none went to waste.