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.