'84 300ZX Ignition Problems

[DeleriousZ]

yeah... well there has to be a logical explanation for it... you're saying the fan ONLY comes on when the car isn't going to start? and NEVER does when it will start fine?

[crx1989]

could possibly be a crank postion sensor or the fuel pump relay.

[MrZ64]

Yes, it only comes on when the car is not going to start. If the car is going to start, it will never turn on. I do know that it's not a relay problem, but I'm starting to suspect that you're right about it having to do the ecu becuase the more I think about it, the more it makes sense.

[Michael.Jones]

Well, I looked for my fuel pump relay where someone said it was (passenger side in front of rear fender) and couldn't find it. But someone said earlier it could be the crank angle sensor; that's interesting because my ECU said that it was messed up. How do I get one of those? The only place I found was Nissan and they only sell it with the distributor which is $500. I already changed the distributor, I got an A-1 from O'reily and I don't think came with a sensor. Ideas??

[stephenp]

well try the connections to the crank angle and the distributer since you said after the timinmg belt change it was fine for 300 miles and they may have nbeen bumped a little and held together slightly better causing it to run a little longer
try cleaning the connections and adding some dielectric grease and see what you get

good luck

[Michael.Jones]

Ok I'll try. Umm...do you know how to do that? I have to remove the distributor, right?

[Michael.Jones]

Hey does anyone know how I go about checking the connections to the crank angle sensor? I don't want to mess anything up because I hear that that sensor is pretty durn important. Thanks

[zxturbo]

It sounds like im having the same problem with my 84 300zxT. My car has run fine until recently. I would start it cold and it would idle fine, but when I drive it would lag and bog down if I accelerated too fast until it was warm. Then I would start it hot and I would have to keep it revved above 2K so it didnt die. Now it will not start at all but it turns over. I am getting fuel but no spark. any suggestions?

[HateNissan]

We have a 1984 Nissan 300 ZX with no spark. New ECU. Coil, Distributor and all associated hardware is new or good.
Turn on the ignition key and the ECU does not bulb test or give error codes unless you momentarily ground terminal 6 whereupon it will give codes (only AC errors) and then won't turn off when the switch is turned off. Dealer won't work on it and Nissan USA knows nothing and doesn't want to help.
Below is attempt to fix summary:
I will first list parts replaced:
ECM 3 times
LED assembly in the distributor
power transistor
cylinder head temp sender (from a trouble code)
coil
EFI relay
timing belt

Things done and checked:
Checked output from dist to ECM, got the 360 signal and 1 other signal (assuming #1 cyl) with a good oscilloscope.
power to + side of coil
power to ECM
All grounds I could find with help from Alldata and an 84 300zx troubleshooting disc.
Condenser between coil from and ground @ dist base

Engine cranks normally, no spark from coil secondary. Checked and found no pulse on - side of coil.
Ignition on, ECM would not boot even with power on the proper pin at the ECM, unless a momentary ground of the #6 red wire at the ECM, from the EFI relay. Once powered up, turned screw to get codes, got 2 relating to the A/C. However, when ignition switch off, the ECM stays powered up (checked for 15 minutes) until ECM physically unhooked from harnesses. I have contacted the local Nissan dealer, and they disavow any knowledge and desire to tackle this, so in my shop it still sits.
If anyone there has any ideas, information or experience with this type problem, I sure would be grateful for help."