My money is on that Hyrdo electric pressure actuator. My mate converted an XR2 which he now has given up on after fucking up the wiring after i offered to do it for him. He had the exact same things, fuckloads of pressure but none from the injectors, EXCEPT when he flicked the ignition off, and there was a brief spray. Turns out he wired the pressure actuator to the fuel pump relay somehow, (fuck knows how but hey), and after putting some temporary wiring after i suggested it he got fuelling at the injectors. Pulling the plug off should achieve the same result, very quick and easy test.