Fuel gauge always goes to full when running

[GrumpyOldTruck]

I've replaced pretty much everything on my fuel system

fuel pump
fuel filter
fuel regulator
fuel injector spider
fuel relay
sending unit

whenever I start my truck the gauge goes straight to full and stays there as long as my truck is running, however when I turn my truck off the gauge goes back to where it's supposed to be. Any ideas? Is my gauge bad?

 

[twomanymontes]

It sounds like there is an open in the circuit. Most likely between the gauge and sending unit.

I'd try and find the connector near the tank and check the ground and the power supply. I believe it should have either 5 or 12 volts. They will be the smaller of the 4 wires to the connector. Not 100% sure what colors though. But, I believe the power wire is purple and the ground is black with a white stripe.

Hope this helps

 

[GrumpyOldTruck]

ok thanks, i'm gonna check the grounds and then the voltage. I didn't have this problem before I replaced my fuel pump. hmm

 

[twomanymontes]

Then I'd check the connection for sure. Or could the float arm be stuck in the up position?