I bought a VG30DETT swapped 1985 z31 as a project and I can't get it to run. The guy said it was faulty injectors keeping it from starting. I replaced the injectors with bigger 880cc injectors and cleaned the fuel lines and tank, checked the fuel pump, filled it with premium, cranked it... And cranked it... And cranked it. And no dice. I replaced the PTU, spark plugs, and coil packs and it still won't start. Any ideas?

does it have spark? and are the injectors firing?

not 100% sure but typically injectors have a constant 12v and the ecu grounds them. i would check for voltage there.

You replaced the injectors with larger injectors. Did you get a chip for the ecu calibrated to the size injectors you are running? If the ecu thinks it has stock 370cc injectors and you put in 800's the duty cycle remains the same and you put in more than twice as much fuel as it should have and you will fuel foul the plugs. Testing the old injectors is as simple as measuring impedance of each injector. The seller may believe the problem was the injectors but he could very well be wrong. The place to start is by checking the ecu for codes. Then determine if you lack spark and or fuel.

BTW, injectors fire on saturated voltage much like a coil. They receive a constant hot and a 5v square wave sent from the ecu actually triggers them.