Fuel Pumps not priming

[Gregory347]

Noticed my fuel pumps not priming. Car starts ok just an extra second cranking. Car has after market fuel system using factory fuel pump power harness for prime and to close relays. Pumps have separate power source. Guessing there is a signal to the FPDM that provides timed power to the harness for priming when door is opened. Then constant power when start is initiated. Has anyone here lost prime to pumps as a result of a faulty FPDM or any other reason? Thanks

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[illadvised]

What fuel pumps do you have? Is there a check valve? I know the old dw400s didn't have a check valve, or maybe yours is faulty. I think what happens is the fuel line drains back into the tank, and the pump needs to run for a bit to get fuel all the way to the engine