fuel wont pump up

[the evil twin]

If the vehicle was running and has starved of fuel (assuming it didn't run dry) then you will need to find the reason and fix that first.
Split line or whatever...

If it is a CRD they can be a real PIA, try filling the fuel filter manually, take off the filler cap, prime as much of the hose as you can and pump and pump and pump.
Don't, whatever you do, crack any lines or unions on the hi-pressure rail side...