20 Most Recent 1986 Nissan 300ZX Questions & Answers

Dear llama470: there is a fuel pump relay located in the worst possible place Nissan could possibly think of! In the right 1/4 panel just forward of the wheel house. You have your work cut out for you if you want to get to it.
1st remove the sill plate from the door opening.
2.nd remove the trim panel which goes across the roof behind the seat (most 300ZX's are "t" tops")
3rd carefully gain access to the interior 1/4 panel. I gave you these instructions because the plastic gets very brittle and cracks easily when stressed. Anyway, as you remove the panel, just about 1.2 up the 1/4 just behind the door striker is a GREEN relay. That is the starter relay. The relay is energized by the ECM. There is a black wire with a few traces or red dots along the way which will end up going to pin # 108 on the ECM connector. If you ground this wire, the relay should click and the pump should run. Most Japanese cars make and break the grounds, not the positives, so the positive will be hot as soon as you turn on the key. The reason it will start then die, is because the fuel pump has two circuits to run on. One relates to the cranking circuit which will energize the relay and the other will only energize it after the car has started. This was designed so that if the car were in an impact, the impact would kill the fuel pump. NOW, The ECM is what runs the relay after the car has started. you may need to try another ECM.
The fuel pumps are easy to get to on this car. Remove the foam insulating floor covering behind the seats and you will see a large round metal plate with a wire harness going through it. There are quite a few bolts going around the perimeter to retain the plate. NOTE! BEFORE YOU REMOVE THIS PLATE, BE ABSOLUTELY SURE THE PUMP DOES NOT RUN.
Here is another way you can check:disconnect the starter solenoid and with the help of a friend, have them hold the key in the start position. You should hear a kind of shishhhhing sound coming from around the fuel lines. Also, prior to turning the key, pinch the fuel hose where the fuel filter is and you will notice it is easy to pinch flat. If the pump is working, when you turn the key to the cranking position and hold it, try pinching it again. The hose will now fee; some what hard. This would indicate it has fuel pressure, thus indicating the pump is working. Which means is all likely hood the ECM is probably the culprit. Most other components wont keep it from running, it will just run badly. Let me know how you do. Good luck

1986 Nissan... • Answered on May 15, 2019

Are you sure you have the correct gearing for the differential? It appears there is alot of torque being applied and it is causing the spindles to shift. Check your springs also.

1986 Nissan... • Answered on Feb 18, 2018

check for fuel compression, gas filter and try, a gas treatment, you buy it at auto zone the gas treatment is suppose to clean the jets . if you think is a valve issue then you should give it a compression test I would use the type gauge that screws to the piston hole and check each piston for compression. good luck.

1986 Nissan... • Answered on Feb 04, 2018

Sounds like computer issues from the cables being on wrong

1986 Nissan... • Answered on Jan 11, 2018

-Possibly the main fuse or possibly there is a relay for all of those circuits. Check it out. Good luck Mai

1986 Nissan... • Answered on Dec 15, 2017

A fuse in the fuse box may be loose.

1986 Nissan... • Answered on Nov 19, 2017

check for a blocked cat converter could be a problem EGR valve

1986 Nissan... • Answered on Nov 05, 2017

Check intake manifold gasket for leaks. Do It Yourself Diagnosis and Repair

1986 Nissan... • Answered on Aug 05, 2017

if you are running an amp, you need a much thicker positive wire coming directly from the battery, i pushed through the clutch linkage grommet on my 85 300zx

1986 Nissan... • Answered on May 27, 2017

battery going bad in key.. need new battery and reprogramed to security system..

1986 Nissan... • Answered on Nov 13, 2016

if I remember when you unplug these and the car starts the MAF is bad and the computer goes into backup mode.

1986 Nissan... • Answered on Jul 06, 2015

I suggest disconnecting the mass airflow sensor and see if the car idles. If the car starts then you have a bad sensor. The next step would be to inspect data on scantool and look for scewed coolant sensor reading . coolant sensor readings should not fluctuat. Good luck I’m happy to assist further over the phone at https://www.6ya.com/expert/richard_9a19ee73dfa4686a

1986 Nissan... • Answered on Jul 02, 2015

You should be able to do this without taking anything off. There is and tensioner/idler wheel that can be loosened on the belt line by the alternator. One bolt will loosen it to a point that you can remove the belt. Pay attention to how it runs. There will also be a belt diagram on a sticker under your hood. Remove, replace and retighten the idler wheel ( I use a crow bar or long piece of pipe to apply pressure) You will see what I mean when you get to this point. Tighten the idler back down and you are done.

1986 Nissan... • Answered on Jun 23, 2015

Probably best to install whole new circuit, such as from ignition switch ON position (or straight from battery if you want it always hot) thru fuse of amps you think yu will need and then to lighter.

1986 Nissan... • Answered on Jun 18, 2015

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