zx killing alternators?
 

Ok i have a 83 zx n/a. I was running a rather large sound system when i got it drove great for many months then the alt died. I figured that the sound system was just way to much draw for the stock 60 amp alt. So i removed the system and replaced the alt and all belts while i was in there.
Went back to normal charging everything was great for about a mnth. And the new alt failed charging dropped to 12.6 at idle. So i replaced it again since it was still under warrenty. It last only about 2 hrs about 6-8 start ups. Then failed and down to 12.3 this time.
I am going to go through the whole system and look for some sort of short or something i really dnt know what to look for. I am hoping somebody will have some tips or have run into this type of problem before.
Next step is to do the maxi fuse upgrade get rid of the fusible links, big 3 alt cable upgrade and the gm one wire alt upgrade that i have read about on here.

If anyone can point me in the right direction that would be great. I have searched threads looking for for a similar problem with no luck. I do have the fsm and thats what im going to use to go through the starting and charging systems. Please help thanks guys.

GM one wire 100 amp alternator!

x2. Unfortunately the 280zx remans fail all too often. If you can drive your car to your parts store, they can do a battery / alternator load test.

+1 on the gm 100 amp. ill never use a stock alternator again. its possible that the wiring to the fuse center and battery has a problem as i replaced mine with 4ga wire. i also did the maxi fuse upgrade. stock wiring is one wire going to 2 10ga wires splitting to the fuse panel and the fuseable links. the joint where they wires connect is near the fender fuseable link area, its not all that great looking, kinda poor actually and just some tape protecting it.

Well i havent had the time to go through all the wiring, but i did pull apart the fusible link area. All the contacts are clean and have good connections. My local parts house only had an 80 amp gm one wire so i went ahead and put that in. Drove around a while charged great at 15volts. That is until i went to work got about 3 miles down the road and zap no more charging. But this was with the lights on... is there some junction point where the lights could directly affect the charging system? But then again the last one it burnt out, i never even hit the light switch... Any direction would be a great help. Thanks guys. going to upgrade the maxi fuses this weekend.

may have found problem please help me confirm it.
 

Ok so i spent last sunday. Pulling out all the extra moded stuff that i did not put in myself that i had no idea how it was installed into what systems.. alarm system that was no longer functional including drivers side door actuator. Racing push button start. Home made Interior leds.

Ok so this is a list of removed items and the problems they cured.

So the alarm was tied into multiple systems. Pulling it out. Restored my passanger door lock actuator contoled by the drivers door. Turn signals now working again as well.

Leds had no effect that i know off guess they were installed in a proper fashion.

Racing push button start. I believe this was installed because the actual ignition switch "start position" dose not function no power sent to starter through the yellow wire.. but i do hear the ignition relay click?

So if im reading the fsm schematic properly the yellow wire is a direct line to the starter. power from the batt through the fusible links to the ignition switch via white with black strip. Acc power routes through the ignition relay which is also part of the charging system. So if by running the push button start has cause a short in the ignition relay or if it has just failed. This could be causing the alternators to burn up the rextifiers??

In addition i also got the maxi fuse upgrade done. Wasnt able to source a big enough distribution block so i had to use what was available. ( yuma az is a very small place with not very much around closest larg towns are 3 hrs away) anyway had to go with wallmarts dual amp aplication distribution blocks not as clean as i would like but it works and gets rid of the fusible links. I also ran larg gauge wires direct to the alternator neg right to the batt and power through the dist. Block with a 60amp fuse hopping this would baypass the problem. It did work for a couple days. Then the alt died again. I did get a gm one wire although all the parts had was an 80 amp it burned that out to so i exchanged both the hatachi 60 and gm 80. Course i sacrificed the 60. Hope to solve this soon have the ignition switch and relays on the way.

Those of you that hung in here with me and read this post through heres some pics lol ;) any advise would be greatly appreciated

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its weird that after all of that your alt burned out again. the fuse box looks good and your using sufficient wire size as well for the alt leads. how tight are you pulling the belts? if you go too tight it will screw alternators as it puts side load on the windings. next to check is the wire that runs to the fuse panel from the power block. take out all the fuses except anything that makes it run. this way you know what system to check. do you have a multimeter? use it to check for any draw on the systems that are still energized if it still kills alts. unhook the stock volt gauge as well, its trouble. mine used to read 10v at 12v and it was killing the stock 60amp. i put in an autometer and tada problem solved.

What kind of Battery you have?
 

Was Wondering how old your battery is and how many Amps? For me Higher Amp batteries help the Alt last longer. Maybe the Alt is charging all the time without a break. The regulator would have to come on more often charging the battery. A higher amp battery draws all the energy in and hold and stores it better. Don't know what kind to stereo system you have but them AMPS draw hard. Think mine is a 90 amp most cars with lots of power assy's have at least that but a good bit of that power needs to be stored.

Yes it is very disappointing after spending almost a full day on her my main problem had not been resolved. But looking at the bright side I did get a few other minor problems fixed.to answers your questions. I’ve always tightened my belt to have minimal torque on the pulleys. In this case for the alt I can reach down inside and with a little force I can spin the alt pulley without moving the belt. But while running the alt pulley is able to rotate at normal speed with no slipping.
Which wire would you be referring to? “ next to check is the wire that runs to the fuse panel from the power block.” If your talking about the main lead that powers the interior fuse panel. If there was an issue there wouldn’t I have issues in just about every other system in the car?
Yes I have a multi meter problem is that this is my daily driver I leave when its dark so I can’t kill all the other systems and wait till the next alt dies. This one lasted 3 days. With bypassing the factory wiring I was assuming that the volt gauge was just reading battery power not charging power. Would this not be the case? As I did leave the “T” plug disconnected but that is just for the idiot light is it not?
Interesting I have noticed a bounce in the volt gauge I wonder if this could be my problem as well
Thank you for the input.

Battery is new replaced it at the same time as the first alt mention in the beginning of the post. I use to run all red tops but started having a starting problem with the gel type batteries in cold weather tried the hybrid gel acid after that and have settled for the slandered acid. Now I run the super start platinum dual posts. At this point in time im not running a radio at all i pulled the system out all together the radio itself is not even powered.

inculded a pic of my Z in its current state now that ime in smog free az i cant wait to get engine upgrades going but first to finish off problems. thanks for the help guys.

Nice looking Z
 

How are your body grounds and engine grounds other then the main ground?

Thanks wana get problems fixed do the bumper mods tben ready for paint..
Cleaned sanded them down at the batt frame an starter. I hit the basics first. Fresh conections at the alt

Ok who has that quote in there signature "SHADY IS CORRECT AS USUAL" LOL
Well I pulled out my triple gauge removed the stock volt meter hooked up some leads to the stock output points for the gauge replaced the alt AGAIN (stock) hooked the leads up to my multimeter and ran for a week no issue. Charging properly. Put in the 80 amp gm one wire. Ran for another week. No problems. Until my son left the lead hanging out the door and I drug it all the way to work. No charging so I was like fuk. Swapped back to the stock went to replace the 80 maxi back to the 60 and low and behold the maxi system worked lol. Now why did I swap back to stock, cuz I got use to swapping them what 6-7 times lol. DAMN IT! :46:

so eventually I'll put back in the gm more then likely when I go to hook my radio and amp back up. So yes the problem was the stock volt gauge as shady had said. Found my extra triple guage swapped in the (known good) volt meter and no more issue.
THANKS SHADY!

I'm curious what it is about the volt meter that causes these problems. A volt meter has a super low draw on any system it's measuring normally. I wonder if it has something to do with the charge indicator lamp...

You know, I have no idea but it would be nice to know. I don't think it would be in the charge indicator lamp because it did cause the 80 amp one wire to fail aswell . In that case the idiot light was not plugged in. It could be possible that it has an intermittent or direct short withen itself which the alts rectifier just can't handle? If you like I could send it your way for inspection.

hahah!! great you got it fixed. i don't know whats up with the stupid volt gauge but it reads wrong and causes a huge draw, maybe it shorts or connects something it shouldn't after all these years. everyone should change theirs out when having weird problems. the new aftermarket gauge fits perfect in the hole anyways so it doesn't look horrible. I've been a professional mechanic for 15 years, been working on datsuns about that long too.