Ignition Wiring/Starting Question

[DuoWing]

Ok well to start I wasn't sure where to post this. This thread kind of goes along with this: http://forums.hybridz.org/showthread.php?t=154198

 

What I got out of that thread was that my fuel setup, pump, etc is fine and there's really nothing wrong with it. Anyway I have a question related to the electrical. This is my 76' 280Z with an L28ET that's been converted to a Z31 ECU/MAF setup and then NIStune was added to the ECU. This was all running properly on my 280ZXT before it was pulled.

 

Anyway I've noticed something else when messing with the car. This is just kind of separate, but part of my theory. When I have the car on I can connect my Laptop to my Nistune consult with no issues, when I go to crank the car my Laptop will lose connection. There's ways to diagnose that, but I'm not going to get into it. Anyway then one other thing I've noticed is that when I prime I will hit the 40psi then after the prime cycle stops it will quickly drop to 0. Now one time I had another person crank it to start while I watched the Fuel Pressure gauge. I noticed that even once it started cranking the fuel pressure gauge sat at 0. After a second or two all of a sudden the gauge jumped and suddenly built pressure and finally then started.

 

I'm wondering if this is an electrical issue. Maybe the ECU is losing connection momentarily from the ignition switch? When I go from ON to Start, and hence why I lose my connection to my ECU consult? Sometimes it will start and othertimes it won't. Once running the car idles fine, revs fine, and will idle and run all day long. One other thing I noticed is that when I'll be cranking and say it won't start I'll let off so the key will be back in the ON position and I'll hear the fuel pump run it's 5-second prime cycle again. My Z31 doesn't seem to do this.

 

I read another thread about where a guy's ignition barrel or the connection was worn out so he wasn't having a constant power even while cranking or it wouldn't start. Something to that sort. Any ideas here?

[DuoWing]

Can anyone tell me what triggers the start signal for the ECU? I was trying to test the car by putting the key in the ON position, then using a screwdriver to jump the terminals. It seemed like my fuel pump started working as my pressure gauge was building pressure and it seemed more steady than before, but the car didn't start. Also my batter was quickly dieing so I didn't get far into this test.

 

Does anyone have any ideas of things to test. My car when it runs runs/idles fine. So I don't think there's anything wrong with my ECU/EFI wiring. I'm just having issues starting. Seems like the ECU is pulsing the fuel pump or something. Making me think I was losing or having itermittent power to the ECU during cranking.