Ok sometimes when I start my car my idiot lights stay on for a while. The Brake, Fuel, Door, etc lights stay on. Sometimes they will go off shortly, sometimes it'll be my whole drive home. The car doesn't seem to have any problem running, but when they do go off my gauge lights all get brighter and so do my headlights. I just put in a new alternator a couple months ago thinking the original was bad. I had the original tested and it showed no problem. I'm wondering if the new one is going bad?

 

Did this start AFTER the new alternator was installed?

 

This actually started a few days ago, but the alternator was installed a couple of months ago.

 

Check your alternator wiring, as well as ignition wiring.

 

check your alternator belt, if its loose it will do that. its prolly loosened off after the change out.

 

That's what I was thinking, I actually had put a new belt on after changing it. Once the weather got cold I started getting a horrible squeal and found the belt had loosened, re-tightened it and solved that issue, so maybe the belt is just loose enough that it's not squealing but causing a lower voltage to be delivered. I'm using a cheap belt. I'm not sure what belts are good or better or where to get them. I'm gonna take a look once my car isn't frozen over and I can open the hood up.

 

Alright, checked the belt...It was a little loose so I tightened it back up, this seemed like it solved the problem, but the idiot lights are still coming on. Today though I noticed a couple things a few times my idle started getting real unstable. My A/F gauge stopped reading normally like it wasn't bouncing around as if something was wrong with the ECU or like the ECU wasn't even using the O2 signal. When I went back to restart the car the lights were back on, but didn't go away. Pretty soon my dash lights were really dim, my headunit just turned off, and my fan motor wouldn't work. After a drive on the freeway everything suddenly lit up again and was working like normal.

 

sounds like a defective alternator if you ask me

 

Problems just apparently decided to plague my Z all at once. I went to the ATM and while I was sitting there I turned the car off. Car wouldn't restart, so I had to get a jump. My Uncle and Dad came along. So while the car was idling I pulled out my voltmeter and was testing the voltage across the battery terminals. With no lights, headunit, blower motor, etc turned on I was getting around 13.8 volts across the battery. My uncle said that would indicate that the alternator is working correctly. I turned on the headlights and head unit, I was getting a little lower but still around 13.4-13.5, he said that looks about right.

Anyway I've had a problem for a long time with my blower motor for my heater controls. The blower will at intervals randomly stop, then shortly come back on. Or I can turn it off then on again to get it to come back on. So far if I start the car with everything turned off it seems to be fine, then I'll turn everything on with no problem.

Now all of a sudden I'll start getting an issue where my idle will start to get bad, not even like a slight stumble or miss, but just a really crappy idle. Tonight again I noticed that the A/F gauge on my car wasn't bouncing around like normal as if you were still in warm-up mode and the ECU isn't using the O2 sensor. The idle was really poor, I checked the voltage across the battery and was getting about 13.25v so still charging at least. I get in the car and for the heck of it shake the wires by the ECU, all of a sudden the A/F gauge starts bouncing around like normal, the idle goes nice and smooth, and everything is good. So I wonder if I have two separate problems. ECU wires and blower motor? Or could this all be linked to the ECU wiring? Maybe a ground or wire arcing, causing something to ground out and kick the idiot lights on? Guess I'll have to let the car idle and start wiggling wires.

 

That doesn't mean your alternator is working correctly. It should be putting out volts closer to 14.7. The alternator needs to have a load test.

Also... your "ecu shake and runs better" sounds like a ground problem I have come across. On the 280zx turbos, the lowest ecu plug, lowest wires (2 or 3 black) join together about 2 inches into the wiring harness by a really crappy coupler. I found this because my Z as well (after doing the Z31T ecu swap) would idle really crappy. After hours of trouble shooting I narrowed it down to touching the ecu wiring, then to those bottom wires. That coupler was corroded and the wires were frayed. I chopped it out and soldered the ground wires back together. No idle probs since.

 

Alright, so I'll have to go put on my original alternator as it was tested at the auto parts store and found to be good, then I'll go get my remanned tested out.

Anyway, I think what was the lowest plug became the top most plug on the Z31 setup, with the way the ECU is mounted so it lines up with the bolt holes. Anyway that splice is located inside the cabin then? Or would that be outside the cabin where that splice is? I think I remember looking for that coupler before and not finding it, but this would be for the two ground wires that are grounded on the intake manifold, correct?

 

See attached pic... the wires join together about 2 inches into the harness from the ecu plug (maybe 2 to 5 inches). It's a crunch coupler (or it was on my harness & my spare turbo harness).

 

Well now that I have a better idea of what I'm looking for I'll go through and seek that out. I do remember when I was running my original ZXT AFM/ECU I had issues with anything over 3500 RPM that was due to the wiring, but I cleaned up the grounds on the intake and it seemed to go away. It may have just been that moving things shook it around enough caused the issue to stay in one place until maybe recently when maybe I hit just the right bump, or bumped the wiring.

 

I was poking around my wiring harness looking for that connector. I believe I found it, I just need a warmer day to mess with it more, but anyway it looks like two solid black wires and they both go into something, but it's covered by some kind of wrapping? Does this sound familiar, or sound like where the crush connector was? Some kind of material surrounds the two wires where they meet up and continues on for a while and inside of this wrapping feels like there's only one wire.

 

Yep... that "wrapping" should be the electric tape. Remove it (you will want to wrap it w/ new e-tape when you put it back together).

 

On my dash my ignition bulb is burned out. Which is basically what the Haynes guide has you go by, but all the other idiot lights work. So would the other idiot lights come on when the ignition light would come on, or are there cases where that ignition light would be separate. Remember this is a Turbo, so my ignition light is in the main cluster with the Speedometer, tach, temp gauge, etc.

Anyway I tried cleaning alternator wiring, I'll try again in the morning, I was poking around my ignition wiring. Found that my connector to my ignition unit had a whole bunch of green corrosion. I did my best to clean all that out. Anyway if I run the car in the day or with no lights, parking lights, etc. My idiot lights do not come on, the second I turn on my parking lights, or go to my headlights, all the idiot lights on the dash come on. When I got to work I left the car idling, but turned off my headunit, headlights, etc. I checked the voltage across the battery and it was showing under 12 volts, but once I shut the car off the battery did have a bit over 12 so it was charged enough to start. I don't know if a bad or corroded ground would be able to cause this problem or not.

Oh and so far it's happened every time without fail. Tonight I was holding the idle up a bit, then turned on the headlights and all the idiot lights lit up without fail. If this is indeed a bad alternator, I wonder if that could be linked to my funky driving issues I've had lately.

Also I've been wanting to do the GM 1-wire swap for a better alternator, but I'm not sure what vehicle to get it off of. Can anyone give me the name and year of a vehicle that one of these came off of so I can get one?

 

I guess it's been too long since I've been in my Z... because I don't remember an "ignition light." Where on the dash is that light?

Anyway... have you taken your car / alternator to a parts shop to have them load test it? That will tell you how well your alternator is working. As for the GM 1-wire... most any Chevy 305-350 motor alternator will work. I think I got mine for an 89? Camaro. I had a crappy old junked alternator that I gave them for the core. I used this "How-To" page to understand more about what is needed: http://www.zcarcreations.com/howto/delcoalt.htm

In a nut shell:
-You will need to cut the wide mount side of the GM alternator to fit onto the 280zx bracket (or fab up your own funky bracket if you feel like engineering).
-Swap pulleys (I had to use a washer between the inside edge of the pulley & shaft to make enough clearance for the alternator fan.
-Hook up the battery wire to the alternator (I had to leave the "charge" wire disconnected).

Done. I've put about 2k miles on that alternator... pumps amps like a champ!

 

The ignition light is in the upper right corner of the main gauge cluster. It's in the series with the Brake, Door, and other lights. I know one of the ways they have you test it was by grounding one of the prongs on that little T-style connector that plugs into the back of the alternator, and when you would all those other lights would light up as well.

I'll have to take the car up to the auto parts store. I didn't know they could load test it, or at least properly load test it in the car.

 

That light should say "CHARGE" right? or for the non-turbo model it's the "LIGHT & KEY." Or does it actually say "IGNITION" ?

Give your local AutoZone / Napa / Kragen / Checker a call & ask them if they can test the alternator if you just bring the car to them. All the AutoZones here have a cart they wheel out & hook up to the battery while you rev @ 2k rpms.... but I've heard that not all parts places do that.

 

Would that be essentially the same thing as if I just put a voltmeter on my battery and had someone hold the car the at 2k rpm? Maybe it does say Ignition, it's never actually lit up for me to see it. The bulb appears to have burned out. I guess I should remove the cluster and replace it. Once you do the GM alternator switch you wouldn't even have that light anymore would you?

 

Yeah... that light says "CHARGE"

Yes you can use a voltmeter & watch the volts when you turn on the lights / accessories. Same basic idea... but the AutoZone test would be a bit more reliable (says I anyway).

When I did my GM alternator swap, I kept the charge light wire disconnected.

 

I'm wondering if the regulator is going bad or something, would a faulty regulator still allow the car to run, and charge, it just would cause issues with extra accessories and such?

 

If you are going to test the alternator go ahead and cover all your bases...test the battery as well. Not when the car is running...take it in and have it tested. You never know.

 

Yeah I'm lazy on this one, but this is odd. I finally decided today that I would stop beating around the bush and go fix that ground wiring on the ECU that nismo clued me in on. Well after doing that my car seems to start up smoother, my A/F gauge seems like it starts reading quicker, and my idiot lights stopped coming on. This is weird, but I guess it's quite possible that a faulty ground in the ECU could cause the problem?

Although I wouldn't be surprised if the idiot lights going off is some sort of weird coincidence.