Is fuel issue

[Kiko]

Hello all. I have a Cummins isx 400 st2. 2003. Truck started and ran for 30 seconds then shut down. Checked the compu valve pressure fitting and no fuel. Pulled the plug to lift pump and had power and ground. Changed lift pump as I thought it had failed. Still have power and ground to new pump but won’t prime. Took inlet line off and inlet fitting. Nothing found. Can fill line with fuel and it won’t suck it out. Wondering what could be wrong internally for lift pump not to suck fuel. Any help would be appreciated.

[Kiko]

I guess another question is that doesn’t the fuel lift pump go directly to the pressure fitting at the top compu valve or does it go through the fuel shut off solenoid first. I could see if it does and the solenoid is no good then it wouldn’t pump fuel to the pressure port.

[Rawze]

you could always take the guts out of the fuel shutoff solenoid and see if it primes.

[Kiko]

Thanks Rawze. Figured out the problem. My lift pump had 12 volts and good ground but the wiring was bad at the fuse. It wasn’t making good enough connection to allow an amp draw from the pump. While testing with multi meter I saw 12 volts and ground. Decided to run an alternate power and ground to pump from battery and everything came back online. Traced it back to bad connection at fuse. Again thanks.