Replace fuel pump, no key on pressure

Need help; new fuel pump. Now there is No fuel pressure to motor until I crank and crank then starts, runs and drives fine. Shut off no fuel up top again. Is there a relay ? Is it a fuse? Is it a switch to fuel rail, gone bad. Battery was disconnected at time of replace. Help use to start right up 1.5-3 seconds . Xj40 3.6 (6) , 1989

Welcome to the Forum I will move this post to the correct place, this is for the earlier XJ 6 S1, S11 and S111 cars, don’t worry this is a common mistake new members make :slight_smile:
Sounds like the non return valve has failed, have you tried cycling the ignition on and off a few time and then try to start? This primes the fuel rail with a small burst of fuel each time.

Sounds typical of the symptoms of a failed fuel pressure regulator (FPR) which should hold fuel pressure in the fuel rail after engine shut-down to facilitate the next start (where 40 psi is required before the engine will fire)
As Robin suggests, try the ‘key cycling trick’ - that provides a priming burst each time you switch on the ignition to build up pressure in the rail before engaging the starter.

Another, but less likely possible cause which has a similar effect is the failure of the NRV (check valve) in the oulet of the fuel pump line which then allows fuel to leak back in to the tank on engine shut down to lose the ‘hold’ pressure in the rail.