Truck Repair: cummins n14, cummins n14, filter heads

Question
QUESTION: I have fuel problem can't get fuel to my filter housing i fill filter and it will move it to injector line and i can keep it running until filter is empty but wont pick it up from tank and it has vacuum because i hand tight filter after running it gets tight that i have to use filter wrench to losing it up to fill again and blew air line from filter to fuel tank no blockage

ANSWER: Is your filter before the fuel pump or after if its before I would first take and hook a suction line from a bucket to the pump and see if your motor runs if it does then would take the line off going into the filter and run it out of a bucket if everything works there I would say you have a pickup tube broke or sucking air if it doesn't then most filter heads have a check ball in them same as the pump I would say you have one of those sticking. another thing you might check is if you have cloth braded fuel lines they could be collapsing.

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QUESTION: New hose, new pump,no ball in filter housing , filter before pump,all lines filled with diesel and have manual pump pumping into it while cranking

Answer
Whats sticking in my head is something wrong with the pickup tube in the tank. Think your going to have to play process of elimination. unhook the suction out of the pump and hook a hose up out of a bucket. If it runs hook it all back up then repeat for the line coming into your filter housing. then move back to the next connection til you get to the point it acts up.