Electrical issue with fuel system. Need help

[Blackbettytt]

I'm the pround new owner of a 107000 mile nissan 300zx twin turbo, but I will say so far the relationship hasn't been pleasant. When I purchased the car previous owner stated it needed a fuel pump it ran, but took some time after started to run correctly. Long story short I believe I have an electrical issue. I can say without a doubt that the fpc is shot, when bypassed the car fires right up and runs great, but here is the kicker in the process of diagnosing this issue I have seemed to lost signal from the ecu to the fuel pump relay. (Pin 18). With some more diggin I found that from the relay back to the ecu I'm getting voltage and not ground. It's my understanding that the ecu sends a ground signal to relay. I have all the proper voltages at the relay. When I manually ground pin 18 relay clicks in and pump primes. Why would I be getting voltage back from the relay into the ecu?

[DCaff300ZX]

Welcome!
Sorry I can't help here and so far no responses, have you tried a fuel system specialist for any clues to what may be occurring?
My first thoughts and surely yours are a short somewhere, but assuming you've made that sweep and found nothing out of line, other than replacing components I am clueless where to go next and would be visiting my Z specialist...do you have one of those? I know tons about the Z32, but not nearly everything so really that would be my next step. I've had two issues that were beyond help in any way except teardown by a specialist so that is why I accept that route as a viable alternative.
Good Luck with that and if not, hopefully someone else finds this and has an answer.