I am a custom painter, and I have the 1991 300zx (NOT a TT) from hell at my shop! The customer brought me the car, and told me it had electrical problems and I would have to jump start the car every day if I had to move it. It loses the charge overnight, even though he had just put a new battery in the car the day he brought it to me. ( He has returned the battery twice to make sure the battery is new and good) The first few days when I had to move it, I put my jump box on it, and it would start right up with no problem. I let the car run for an hour or so, and the car would start right back up for several hours, even a few days at a time? The last time I went to start it to move it, it was dead, I put the jump box on it, and all the lights, everything came on as usual except the starter will not engage at all? Today I pulled the starter out and took it to be checked. It is fine. The Tech told me when the battery on these cars goes dead, or is diconnected the starter is disabled by the security system and you need to do something to reset it? I have put the car back on level ground, locked and unlocked the doors many times then tried to start it, NO GO! I have tried everything that I have read on this site to fix the problem and I cannot get it to turn over!!!!!!! Can somebody tell me what to do to get it going? I have disconnected the battery for 24 hours, ect that this site has said to do! I called the customer and told him what is going on, and he said the car ran when he brought it, and it is my problem and it is a big problem! Any help would be appreciated! Thank you in advance!!!
Batman

 

are all the doors and hatch closed before you try to unlock...oh yeah also make sure the hood switch is down (or hood closed)
another thing, did you try to unlock the other door? maybe the drivers door switch is screwed and doesnt do anything when you unlock.
The Z alarm module is located under the passanger side floor board up above the ECU, unplug it and try to start it
good luck

 

The doors are secure, the back hatch and the hood. I have locked and unlocked the drivers and passenger side doors many times with no luck. I have unplugged the security system by the ECU and No change. I even turned the screw on the ECU all the way out and then back again! I have tried everything this site has offered with no luck? The alternator is not the problem either, it charges the battery like it supposed to when the car runs. I have jumped this car at least 5 times with no problem and all of a sudden this last time it locked the starter? I had the starter checked and it is fine. I am ready to scream! I live next to the bay, and this car if I push it once more is going in it!
Batman

 

There is no security lock on the starter that is triggered by a dead battery, that's absolutely rediculous. It's even more rediculous to say there's a way to reset it.

It has to be an electrical issue. Did you try jumping the starter (bypassing the ignition switch and just powering up the starter with a wire straight from the positive battery terminal while the key is in the on position)?

If you can't figure it out, I'd suggest posting this in the Technical forum of TwinTurbo.net... it gets significantly more traffic.

 

i had that same problem on my old Z

i had the security relay replaced, and it worked fine

but try to directly power the starter like zlover said before buying anything. i never thought of that

 

i had the same problem with my z...there was a few times when i disarmed my alarm and tried to start it up...nothing happened...then i tried to just unlock my driver side door with the key with the alarm disarmed...and tried to start it up again, it worked...i know this might sound kinda stupid ...but give it a try...i think it was part of the security system that i have

 

*ditto

the starter signal passes through the security relay, if it is not closing as it should when the security system is disarmed then you will never get the starter to work.

try bypassing the ignition system by starting the starter via battery with key in on position like was previously suggested, if that works I would check the security relay.

edit:Lol... just read the last part of the post I quoted... i guess i just reworded his post

 

This is a definite possibility, actually. I've known several Z's that have bad alarm switches in the doors. For example, with my first 300ZX, unlocking the drivers side door would not deactivate the alarm, so I had to either pop the trunk or the passengers side door first. With my current Z, the passengers side alarm switch is bad, so I cannot open the passenger side door first. If the battery is dead, the alarm might not sound, but it still won't send any signal to the starter because it'll be as if the alarm is still activated.

To test this, simply unlock both doors and then the hatch, before opening anything.

Otherwise, the relay could be a source as well (as previously stated).

 

I am unable to play with the car today, as I am in the paint booth all day. We managed to push the car into the shop last night, but I can't get to it until tommorrow. I have locked and unlocked all doors, hatch, hood etc in every order you can think of with no luck. The drivers side lock locks and unlocks itself when I put the battery charger on it though for at least the first five minutes until it starts to charge a little? It just sits there and locks and unlocks back and forth. Never seen that before either! This car is posseessed! I let you all know what happens tomorrow..............

 

I actually have this problem.....the stock alarm will not shut off by the driver door, I have to use the passenger door to shut it off. A pain, but I am not too concerned. I should have the doors apart soon to replace some speakers, so I can fix it then

 

just a thought, have you checked the clutch switch if it's a manual or the gear lock switch if it's an automatic? Either one of the switches could also cause the intermittent operation you speak of if the wiring to them is faulty.

 

good point... I second checking these as well.