This may be a weird question; but on which side of the fuel filter assembly is your inline K pump located?
If it is after the filter, then something on the new fuel filter assembly is leaking air and not allowing the inline pump to build up vacuum all the way back to the fuel tank.
If it is before the new fuel filter assembly (between the filter & fuel tank), then I would take a real hard look at the pump itself and / or all the fuel lines, connections, etc... all the way back to the top of the fuel tank.
Also, some inline pumps do not allow fuel pass through if they fail or are not running! So manually pumping the primer pump is a waste of time if this is the case?
Many, including myself have installed the in-tank lift pump due to it's many advantages of putting the entire fuel system under positive pressure when running and it will also allow fuel passthrough if it were to fail for any reason. This feature also allows the manual fuel primer pump on top of the fuel filter housing to function normally and / or allows the CP3 the ability to suck the fuel from the fuel tank as it did when it came from the factory...
If you disconnect the fuel outlet hose from the K pump and cycle the key and nothing comes out of the inline pump while it is running, then either it has gone bad, or you have a leak on the suction side of the K pump allowing it to suck air and never build up any vacuum...
Good luck, and keep us posted as to what you ultimately find wrong...
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Supporting Vendor and Moderator of LOST05 Jeep Liberty CRD Limited
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