Nissan Repair: 1987 nissan pathfinder 4 cylinder - injectors not opening/not getting power, crank angle sensor, noid light

Question
i have a 1987 pathfinder. now, the original issue with it, was that someone had broken into it and stole the ECU. i eventually found an ECU at a junkyard from a 1986.5 Nissan pickup with the same motor. we hooked it up and it seemed to work fine. except for one thing. the injectors on the pathfinder aren't opening. I've been told that its got fuel pressure, the injectors are good, and all that. they say that they're not receiving power. so now, I've been told that they think either the ECU is no good, or that for some reason, the ECU isn't compatible. could it possibly be that the injectors are bad? or is it the ECU?

Answer
Mariah,

The system will have to be diagnosed to determine if the crank angle sensor is sending the signal to the computer to fire the injectors.  After that, you need to see if the injectors are pulsing.  Get a noid light and connect it to the injectors and see if they are grounding.  If neither of these work the ECM is defective or the wrong one.