# Trouble with 85 300 zx



## Justice300zx (Mar 31, 2017)

Sat for year and having trouble. Fuel pump won't cycle on sometimes to get the car started. Once running it held 35psi just read 0psi when cranking I've had it started with ether few times and seems to cycle on. Codes 13 14 23 31 
Has been giving me issues running rough have to hold it 3-4k warm it up b4/it stays running. I had unplugged tps and ran fine for a mile b4 and started missing out. Restarted vehicle fine after its warmed up and made it home barely. Next day it needed the sensor plugged in to run. I unplugged maf and car idles fine doesn't lug just hits limiter at 2k rpm and appears to Run just fine. Plugged maf in and car had trouble idling and wouldn't Rev just bogged. Killed it car cooled off cleaned maf with maf spray cleaner now can't get it to start with ether. And seems like it fuel pump only cycles once cars started but may be faulty. I'll check to see of pump wire is getting power. Question is is there anything that'll kill ignition, injectors, or fuel pump cycle causing car not to start


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## Justice300zx (Mar 31, 2017)

I'm going to try and direct wire fuel pump if it isn't faulty. Is there relay or any thing that will kill inj, fuel , fire. Any one know of good 12v source under dash for pump switch


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## Justice300zx (Mar 31, 2017)

The easily accessible circle 4 wire in tje rear is just for the fuel sending unit.? Does anyome know if the 3 wire is the fuel pump harness and which is power ground so I can direct test fuel pump? Does have trouble starting with ether but I'll give it another try after charging battery


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## smj999smj (Jan 1, 2006)

It's been a while since I worked on a Z31...but, I remember a little bit. There are two access covers in the rear. One covers the fuel pump module, which I believe is the one closest to the driver's side, and the other covers the fuel sender module. Unlike later model Nissans where they are part of the same module, they are separate components on the Z31. Sometimes the connections on top of the fuel pump module will corrode and cause poor connections. A bad fuel pump relay could also cause intermittent operation of the pump. The fuel pump relay would be the best place to start by jumping the harness connector terminals for the "switch side" of the relay. I would highly recommend you get a factory service manual for you car to give you access to wiring diagrams and diagnostic procedures. You may be able to find a free, downloadable version at Nico Club's site.


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