Have a 1986 nissan 300zx V6 non turbo wont start, hear fuel pump runnung no oil pressure on gauge replaced oil pressure unit still wont start any helpful advise

Sort of.
There should be a relay that provides power to the pump when you first turn the key on.
Then once the engine starts power is provided by way of the oil pressure switch. That way the pump won't run in an accident.
The oil pressure switch grounds the fuel pump relay on some models.

do you have spark? have you checked any of your sensors like crank sensor or cam sensor you said you small fuel I would do a fuel pressure test, befor you put a fuel pump in. please let me know if this helped i could have you do few more tests if needed

stockam auto

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About the only thing left is the Ignition Control Module.

Check to see if she that is the car is drawing air mabey through a broken air pipe.

try taking the sender unit out and checking the connection pipe from the pump to the outlet on the sender unit but first check that you have a spark

REPLACE FUEL PUMP RELAY.SOUND LIKE ITS STAYING CLOSE..

This is more complex and you won't find anyone to give you advice. Dealer solution on this one.
Sometime they don't even know and guessing.

Maybe it's time to buy another car?

a fuel pump here in the us is about 240 dollars, since your looking for the cheapest route, aftermarket should be fine. what a pump will cost in Australia I have no idea

Dear number601513: DANGER!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
Adding oil is not going to make the oil pressure build up by adding more. The system is slightly more than a 4 qt system with an oil filter change. By adding oil, you raise the levels in the engine to areas where it is not designed to collect. Consequently, it is prone to leaking and can smoke by picking up oil through the pcv.
The fuel pump has NO relationship to it's oil pressure. The only relationship would be through providing enough fuel to power the engine speed above 600 RPM which would and should be more than adequate speed to drive the oil pump. The oil pump on the VG-30 is located at the front of the engine and is the last component which is installed prior to to installing the timing belt gear. The pump is crank shaft driven, so it is a positive drive unit and not very prone to failure. The oil pickup tube which is bolted to the bottom of the pump, is sealed by an "O" ring. This is a probable place for it to loose prime. The screen at the bottom of the pick up tube could be full of sludge which limits the flow of oil, thus keeping the oil pressure dangerously low. One suggestion prior to condemning the engine oil pressure, is to do a mechanical oil pressure test. You can remove the oil pressure sending unit and screw a mechanical oil pressure guage in it's place. The threads are not metric, but NPT tapered design. You can buy mechanical oil pressure gauge kits relitavely cheap and make a test tool with one. Due to the fact that the oil pressure gauge is electric, they can give misleading readings. If your readings are down in the 8-10 PSI area @ idle this is bare minimum, when you raise the engine speed, the oil pressure should reach 40-60 PSI. Make sure you bleed the air out ot the oil line going to the gauge beause "AIR" compresses and will give you a false reading.
I hope this is informative. Good luck.
PS, I'm the new guy on the block here in "Fixya" if I've helped you out, please write back in to let them know. THANKS>>>>>>>>>9

may wanna check the distributor could be outta whack (timing).