Hello everyone, can someone help?

The fuel pump failed and was replaced by access to tank gained by cutting floor. replacement pump( from the states) runs and fuel arrives at the pressure regulating valve located at the rear of the rocker cover, this is checked by breaking into the lines at the wheel well, but does not pressurise the fuel system and there is no fuel to allow the engine to fire, sounds a bit af a coincidence that the pressure regulating valve should have failed at the same time, anyone with clues or advice? all very much appreciated, thanks, Mike.