1987 nissan 300zx starts but wont stay running

I have the same problem and working on it. I have found a few connectors that were corroded. I also found my ECU wont turn on it is not getting power from the ignition switch. here are some places you can look. Passenger side behind that battery is your fuel pump relay also passenger side behind the seat another relay. your car is shutting off because the pump is loosing power

OK here is the fix. check both relay connections fixed my problem, Fuel pump relay by the battery and blue relay behind the passenger seat you have to remove the side panels for that one and you have to remove the battery to get the fuel pump relay.

1989 zx300 fuel pump relay location

my injector 12volt all time with out switch

So I've got an '89 300zx and I'm having a problem where the car runs perfect, but only for 30 seconds, on the dot. I've replaced the relay behind the passenger seat, but haven't checked the relay behind the battery yet. Would there be any other problem causing this?

Try checking your fuel pressure regulator