The Stovebolt Site Forums The Shop Area Engine Shop fuel gauge? ???

Hello to all


I have a 55 chevy 3600 pickup and had a question on the gauges. My fuel gauge ain't ready , sonic replaced the fuel sending unit and nothing so I'm assuming its the guage. Should the fuel gauge have a grind on it? My gauge has two prongs on it. Also my trucks wiring has no fuse box none what so ever.

The fuse box used on 1950-1955 trucks is described (for 50-51, which is the same for 1953) in this Shop Manual. Some other circuits are protected by circuit breakers in the light switch on the dash.

"Should the fuel gauge have a grind on it?"
I do not know what grind would be needed on a fuel gauge - ground?

Most problems related to fuel gauges the result of:
- power lead connected to wrong post on gauge (fries the gauge even if you reconnected that lead correctly)
- a bad lead from the gauge to the sender
- bad ground at the gauge and/or the sender
- bad sender unit
- bad gauge (often "fried" by connection of 12v power to the input post on a 6v gauge)

Fuel gauge problems seem to be a common problem. Diagnosis can be tricky, tedious, and confusing. Here is a good Gas Gauge Problems Tech Tip

Typical fuel gauge wiring and operation.

Power ( + ) is hooked to one side of the fuel gauge. It should be a fused circuit.

Power flows through the gauge and comes out the other side terminal post,

Power ( + ) leaves the gauge is on its way to the sender by way of wire harness,

At the fuel tank is the sending unit, center post is ( + ) wire hook up, mounting pad with five screws is the ground ( - ) side of the circuit.

( + ) flows through the sender to reach ground ( - ). If the tank or sender is not grounded properly, the gauge will not function.

The fuel level varies the resistance to ground, so the gauge needle varies from full to empty depending on the resistance in the circuit at the sender.

YOU MUST HAVE A CLEAN GROUND CONTACT at the sender and truck body or frame.

Run a test wire from gauge to sender and sender to ground post on battery, if the the gauge is good and sender is new, it should work. Its easier to remove the sender from the tank for testing.

Joe

Make certain you have a 30 ohm sending unit. If your sending unit was replaced with a "one fits all" or universal model, it could be the wrong rating.
Jon