Fuel Sending Unit Tests??

[55 Fargo]

Hi, how does one test a 2 wire gas tank sending unit. I have mine out(it's from a 47 Chrysler), and would like to test it before re-using it.........Thanx Fred

[bach4660]

you can test with an ohm meter set to resistance, even without the specs you should see the different readings on full and empty (on the trucks the sending unit is 90 ohms full and 0 ohms empty- sorry don;t know the cars)

[Reg Evans]

For my 40 Plymouth the with a 2 wire unit does it matter which wire goes where. My new units terminals are marked 1 and 2. I couldn't see these numbers on the old unit because of rust so I didn't pay attention to their locations. With the new unit installed the gauge seems to fluctuate from 1/4 to 3/4 depending on engine RPM with a measured 8 gallons in the tank. Very strange.