1986 Nissan Z31 300ZX issues

originally posted by: AutomateThis1
a reply to: RazorV66

I left the lights on

You need to get a voltmeter and the check the voltage at the battery while you crank it over and then try to get a reading while it runs for the few seconds.
You say it only holds a enough charge for 3 to 4 attempts to start it?
Battery is shot and probably the alternator as well.
If the battery was good it should run for longer than that even if the alternator was bad.
You should have a voltage reading in the 14V range, if the alternator is working....12V volts or below if it is bad.
Or.....before you spend any cash on anything, take a known good battery from another vehicle and see if it runs longer and take the readings then.

Disconnect the Alternator from the cars electrical system and try again.

Reverse polarity can do very strange things to alternators.

If it starts and runs you need a new alternator.

P

Alternator. But get rid of that thing. A Camry can out run it. I sold a 2005 RX8 a few weeks ago to a scrap yard. Still ran good but it was worth jack squat and as stated, a Camry could out run it. Unless you absolutely have to have it dump it. Get a Camry.

originally posted by: Stupidsecrets
Alternator. But get rid of that thing. A Camry can out run it. I sold a 2005 RX8 a few weeks ago to a scrap yard. Still ran good but it was worth jack squat and as stated, a Camry could out run it. Unless you absolutely have to have it dump it. Get a Camry.

A Nissan GTR can outrun your Camry. Get a GTR!

Not everyone buys cars on the basis of being faster.

P

Check the voltage regulator. Should be external and replaceable.

Also check if it has a balast resistor on the firewall/fenderwells. They blow at polarity swaps and unchecked voltage surges.

I believe those engines also have an ignition module on the distributor , below the cap mounted to the body of the distributor.
Check that as well.

a reply to: AutomateThis1


It sounds like you fried a Ballast Resistor in your primary ignition wiring, which is where I would start looking. They are designed to protect the ignition components and the way it starts and then dies is exactly what a bad ballast resistor will do. Next check if there is an oil pressure sensor, it will do the same thing if it’s fried. After that start checking any relay in the ignition wiring, you may have cooked one.

Most cars will run without a battery or without an alternator but not both. The alternator will not prevent it from starting or running, it will just run off the battery if the alternator is bad.

Given that it starts and runs I think chances are the ECU and other components are ok.

You can make a simple test light with a 12V light bulb and 2 pieces of wire. Run one end to a good ground and use the other wire to probe your ignition system wires to test that you are getting power where you need it when the key is in the run position. If there is no power, start tracing the wire back looking for any melted or grounded wires.

originally posted by: Notoneofyou
Check the voltage regulator. Should be external and replaceable.

Also check if it has a balast resistor on the firewall/fenderwells. They blow at polarity swaps and unchecked voltage surges.

I believe those engines also have an ignition module on the distributor , below the cap mounted to the body of the distributor.
Check that as well.

Regulator is in the alternator on that one.

a reply to: RazorV66

Yeah, I'm going to do that later today. I got a spare battery.

a reply to: Stupidsecrets

That's cool, but I don't care. I'm not asking for opinions on what my next car should be. I'm asking for input on what all my be messed up on my car from people who may have experience with said matter.

The cool thing is that I still have a complete Z31 on hand, so I'll probably spend all day tomorrow pulling parts out of it. I'll post pics if I can, but ATS sometimes won't display the upload page correctly.

a reply to: AutomateThis1

If it catches then dies its usually a fuel problem. Dont know that car as i usually work on more modern audis. Make sure the fuel pump is sound. Then check air flow, if it has a maf sensor try that. Check your plugs are providing spark to keep it ticking over. If none of the above i would go after the loom since you fecked the jump start

a reply to: LuxFer

Just reached a stopping point on it. I put in a good battery and it did the same thing.

If I had a jack and the right tools I would have swapped out the alternator as well.

I've checked the fuel and air systems as much as I can and everything I checked is working as it should.

I'm reaching out to some friends to see if they'll help me with the tools I need.

Still not able to post pictures.

a reply to: LuxFer

By loom, I take it that's what we call a harness over here?

Yeah, I went over that. I didn't see any burnt or melted spots. What little corrosion there was I cleaned off.

a reply to: AutomateThis1

Out of curiosity, does your car have any thermal inline fuses in the starter solenoid wiring?

I've had that become an issue on one of my mustangs after jump-starting the car to run it, as it was set up for 1/4 drag racing, and had a modified charging system and battery which would overload the factory wiring and melt them.

a reply to: AutomateThis1

I've had 3 300ZXs.
Uh how long was it smoking??
My guess is the wires within the harness could have somewhat melted together before the link blew. It counds like you have a gnarley short. Also you should be able to self check without her running, just put key in on position.

I had some weird electrical problems with one of mine after driving through too many flooded out roads. Its not worth the fun forever.

Best of luck with your issue


Check the voltage at the 12+ power wires at the ECU.



-Driver

a reply to: E38Driver

Thanks. Really appreciate it. It was smoking a good bit probably about ten or fifteen seconds. It was smoking from the fuse box area.

I did a visual inspection of all the wiring, but I'll probably end up cutting all the tape and sleeves to 100% check.

Okay, so as far as the ECU goes. I did that, but both the red and green LEDs remain lit. They don't blink.

I started with the screw all the way counter-clockwise, and then all the way clockwise. The LEDs never blinked. Just stayed lit.

Do you think that means it's fried?

a reply to: AutomateThis1

Sorry dude been busy, yea by the loom i ment the wiring loom, you can find it from you block backwards, lots of wires. Dont panic about everyone telling you its your ECU either. It takes a good surge or a flood of the box to kill your ECU normally

a reply to: LuxFer

If your ECU was cooked it woulnt start. You need ignition timing air fuel.

a reply to: LuxFer

Thanks bud. That's what I figured. It's just been so long since I've worked on a car I just wanted to hear some other people's opinions and experience.

I'm still certain it's just the alternator, but I've been busy with other stuff so the car issue has kind of taken a backseat.

I spoke with my father and he said he would help me fix it. I just need a jack and a few sockets and it shoukd be good to go in less than an hour.

I followed the wire harnes every which way, and triple checked to make sure I hadn't missed anything, and I still didn't see any signs of melting or fusing.

Thanks for the info everyone. I'll post here again after I get the car running again.

Well, it's something to do with the fuel pump circuit.. My dad and my sister's boyfriend pretty much tore the inside of my car apart trying to find what was wrong with the car, and I found that they pulled the fuel pump relay out of the wall and pulled that apart.

Well, I've got it rigged to keep pumping fuel. I'm probably going to junk it. I'm tired of messing with it.