# 1986 Nissan 300zx Refuses to Start



## nonresponsivenissan (Dec 30, 2015)

Hello all,

I am the proud, slightly frustrated owner of a manual 1986 Nissan 300zx Non-Turbo. I don’t have much car experience or knowledge, but I am more than willing to learn and apply what y’all have to offer. Sadly, the car is currently sitting in the driveway motionless as it has done off and on for several months. The ignition appears to have no rhyme or reason and will only start on random occasions. I am in desperate need of some guidance.

As for some back story, I purchased this car from another owner who had preserved the engine of the vehicle but not much else. He had installed a custom audio system and hotwired several wires. It was running at the time and I decided to undertake a minor project as it appeared to mainly be in need of aesthetic upgrades/repairs (stuff I could handle). The car ran great for the first few weeks and I thus decided to fix a few of the minor issues the previous owner had pointed out. I parked the 300zx in the garage and proceeded to replace the brake pads, headlights, and headlight switch. Upon replacing all of the pieces, I proceeded to crank the car but discovered that the battery had died. I then replaced the battery with a brand new one and found that the car turned over but still refused to crank. It was then that I began trying to diagnose the silence.

After reading several similar forums and following the instructions of others, I have replaced the distributor, distributor cap, crank angle sensor, ignition coil, spark plug wires, and power transistor all to no avail. In addition, the car has had an oil change, the tank is filled with at least five gallons of premium gasoline, I have had keys made in order to reset the security system, and I have checked to make sure the fuel pump is priming upon ignition. I am unsure of what else to replace as my knowledge is limited and I’m not interested in throwing money at anything and everything I suspect.

Over the summer, the car randomly decided to crank up and I was able to drive it for several days before it died yet again. In case it helps, I took note of the warning lights which appeared on the digital dash. The “Lights”, “Windshield Spray”, and “Sensor” lights were all illuminated. 

I realize that I’ve thrown a lot of information at y’all, but I simply wanted to be sure and cover all of the bases. Thank you for your time, and I look forward to corresponding with you.


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## rogoman (Dec 16, 2004)

One of the first things to do is perform an ECU code readout. If there is one or more fault codes set, they can help point to the malfunction. If you have a copy of the FSM for your vehicle, the code readout procedure is described there along with a listing of codes. You can download a copy of the FSM sections from the Nico Club web site; here's the URL: http://www.********.com/FSM/ (replace the asterisks with "nico club" spelled as one word). The section ECEF.PDF is the one you need to read.

Here are some things to check for your problem:
- Measure the fuel pressure, it should be around 30 psi.
- There may be a major vacuum leak in the intake system.
- The cam timing may be incorrect.
- Make sure the spark plugs are firing.


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## nonresponsivenissan (Dec 30, 2015)

Alright, so I ran an ECU code readout and collected two separate readouts. The first corresponded to that of a “Load Signal” and the second corresponded to that of an “Idle Switch”. I’ve conducted a small amount of research regarding these two and will continue to do so, but is there anything obvious I should notice about them and/or look for?

I also pursued a fuel pressure reading as well as a cam timing reading but have yet to acquire the proper tools (This should come later). In the meantime, I checked the fuel pump fuse as well as all other fuses and found that they’re good. Should I check for a fuel pump relay or is this piece nonexistent?

Finally, and most importantly, I checked for spark in the plugs and found that *I’m not getting any spark*. The plugs are in decent firing condition as I tested them with another vehicle, but the 300zx refuses to produce any action. The vaccum tubes are also slightly aged but appear to have adequate seals at all connecting points. What steps should I take next in order to diagnosis this issue?


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## rogoman (Dec 16, 2004)

If you're not getting any spark on any spark plug, then maybe the security immobilizer has the system locked out.


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## nonresponsivenissan (Dec 30, 2015)

So what exactly should I look for or fix in order to resolve the security immobilizer? I went ahead and made sure the system was working properly by sounding the alarm. I rolled down a window, locked the doors, and then manually unlocked a door after ten minutes had passed. Upon opening the door, the alarm sounded which told me that the system was at least accomplishing the basics. I also removed the passenger seat in order to expose the security system and found that the previous owner had mangled some of the wires and hotwired others for what appeared to be the sound system. Not sure what to do there...


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