Hey guys I am currently working out some issues with my 75 280Z. The EFI has been removed and replaced with carbs. Lately I have been having some random starting issues. It doesn't happen all the time but once in awhile it will crank but not turn over. I have narrowed it down to the fuel pump cutting off during starting/cranking. Currently the fuel pump is wired directly to a 12v ignition wire from behind the ignition switch. I hooked up a volt meter to this ignition wire and usually 9 times out of ten, it only drops to 10-11 volts during cranking...but every once in awhile it drops to 0. When this happens I can look at my fuel gauge under the hood and it drops to 0-1 psi, which causes the vehicle to not start and just keep cranking.
What i've done so far:
tested for other 12v ignition sources - same result
replaced ignition switch - same result
replaced voltage regulator - same result
oh, and all the wiring has been removed, cleaned, terminals replaced if needed, etc...
Anybody have any suggestions?