We just replaced a bad stock pump with a walbro 255 in a 2000 Chevrolet 1500 with a 4.3.

The the pump works, there is pressure at the rail, and the truck will not attempt to start. I do not know where to go from here. It came in for a bad fuel pump, we replace it and it still will not start.

We could get it to run with the old pump, but you had to bump the bottom of the tank to start it.

Any help is appreciated.

EDIT: I just checked the pressure at the rail @ 20psi.