Modernizing a 55 fuel gauge

[Guest MV10]

Not surprisingly, my gas gauge has always required the services of a 1-800 psychic hotline when I wish to divine the contents of my fuel tank. But the condition appears to be worsening, so I've been kicking around the idea of buying a modern aftermarket gauge and trying to jam the guts into my factory unit.

I realize this will probably require changing the sender, but I'm not averse to replacing the whole tank (and sender) if it helps. Off hand I don't know the voltage range of the factory sender, or if any modern-day aftermarket units are available that will work with this.

Or alternately, is it perhaps the sender that is so flaky, and a modern sender might correct the issue, with no changes to the gauge? That sounds nice in theory. I really don't know. Just started giving it serious thought today.

Has anyone done anything like this? (Ok, I know Captain Moneybags at 55buick.com has been there, but I mean anybody with a less-than-unlimited budget.) Looking for pointers, tips, ideas, warnings, links, whatever.

Hep a brutha out. Thanks.

[old-tank]

Not surprisingly................

Well it is a surprise that you are having so much trouble. I have had a '55 in my driveway or garage since 1962 and have never had a problem with the gauge. The few problems were related to grounding issues with the tank and a float in the tank that leaked and filled with fuel. All 3 of my present '55s are surprisingly accurate...1/2 tank reading = 10 gallons. There are vendors that sell replacement sending units and I am sure there are others that will repair the gauge if defective. This is one case where you don't need to reinvent the wheel.

Willie

[Bhigdog]

There are universal replacement senders availabe. They may require some adaptation but they are only about $28. The float for my chryser was made out of unobtanium but I adapted a universal with no problem......Bob

[NTX5467]

The fuel gauge is a simple volt meter, with the sending unit's potentiometer varying resistance with varying float lever arm movement. As Old-Tank mentioned, making sure the wiring connections are in good condition and the ground connection is similarly good would be the FIRST thing to do--period.

The variable resistance "potentiometer" is on the sending unit. Sometimes, they can wear or become corroded, but can probably be gently cleaned up, if they are not worn out. Seems like Year ONE used to rebuild fuel tank sending units? As you're reasonably closeby, you might check that out.

Again, all the gauge does is read a variable voltage. NO need to re-engineer the fuel gauge "guts". You might get an electrical schematic for the car and see where the fuel gauge's feed voltage comes from--that might be a problem, too, which also might be related to another circuit having an issue you might not be aware of.

Regards,

NTX5467

[stealthbob]

If it helps here is the talk on the gauge for the '54....

Pages from 1954 Shop Manual Full 4.pdf

[Bhigdog]

If you've checked all your connections and the tank is grounded (important) most likely your sending unit is BAD. The unit internals consist of a very fine nichrome resistance wire wound around a thin piece of fibre that's bent into an arc. The ohms should be 35 to 240. The float is connected to a thin phospher bronze wiper that rides along the wire and reads the resistance that corresponds to voltage drop that your gauge registers.

there are many things that can/will go wrong with your sender. THe wiper will wear out and make iffy contact, the float may sink, the bearings float rides in will sieze, the resistance wire will open, the wire will get corroded, etc etc etc. You can take the unit apart (it's riveted together) and spend a day screwing around with it , and make the tiny rivets to put it back together or you can google Moeller Marine then go to Amazon. comm and buy one for $24. The choice is yours. Decisions, decisions............Bob