Hi

okay so today on the way back from stamford car felt like it had bad gas coughing bucking then volts showed 5-6 not 14... soon after car stopped battery discharged. No anything for juice. It sounds like she is not charging to me. I may need a new alternator. But I am just guessing , i am charging ther battery and will try and get her hom last 10 miles on the parkway before battery goes down again. Or I may tow her home and do a proper diagnosis.
Does this sound familiar to anyone.. Battery is new 13 months ago. Anyone have a good source to order an alternator?

thanks

Barry in Fairfield 203-615-1100celltext

Barry

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1983 280ZX 5 speed T-Top Gun metal gray

It could also be a bad voltage regulator.

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'78 280Z

Thanks

maybe it is/ Good NEWS is that I left the car and brought the battery home and charged it edfour hours. I went back b4 sundown and had 12 volts for 9 miles and 10 volts for the last two miles and I got her home in the garage with pressure off to do a proper job on diagnosis. Now I need to learn how to tell if it is the volt regulator or alternator or what. The oil guage and temp guage have been erratic by the way.

Thanks

ALL thoughts appreciated

Barry

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1983 280ZX 5 speed T-Top Gun metal gray

It sounds like the voltage regulator. You will need a volt meter to test things. The following link might be useful.

http://forums.tdiclub.com/showthread.php?t=379701

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'78 280Z

Hey, Barry ~ this happened to me too, many years ago. Pulling up onto the freeway ON ramp, my ammeter suddenly went to "+45" then to "-45" then the car quit. I have my old notes to remind me what I did to repair it but as I sit here I don't recall whether it was my alternator or my regulator. I have replaced both a few times over the years. Today my alternator is internally regulated (by diodes, which do the same thing) so I no longer have a regulator.

As we have discussed on here recently, the purpose of the old regulators was to allow one-way current flow from the alternator (or generator) into the battery to charge it, and then to prevent the battery from self-discharging back thru the alternator or generator when the engine was off.

Normally, the only function the battery has is to spin the starter motor and supply a little current to the primary ignition circuit to allow the engine to start. Then the alternator (or generator) takes over and supplies all the electrical current, and replaces what charge the battery needs to be fully charged again. If you somehow manage to demand more current than your alternator/generator can supply (such as at idle with an old generator), the battery again supplies the remainder. Also of course, when you use the lights/radio while the engine is off, the battery supplies all that power. But essentially your dynamo (alternator or generator) makes all the electricity for your every need; the battery does little.

While the engine is running, the regulator *should* close its internal set of contact breaker points, allowing the alternator/generator to send current TO the battery. When the engine is off, those breaker points *should* open to prevent current flowing FROM the battery to ground thru the alternator/generator. The regulator is the 'guardian' which prevents your battery from discharging itself when the engine is off.

All things electrical eventually break. When a regulator breaks it can allow a battery to slowly discharge itself back thru the alternator/generator overnight, or it MAY provide an instant direct ground which shorts the battery out completely and essentially dumps all the electrical potential at once. (That's what I think happened to me). Your engine dies and a new battery will quickly discharge itself again until you replace the regulator.

As long as the engine remains running, a good alternator will continue to provide power to keep it running, even if your battery is flat dead. But once you shut the engine off, a dead battery of course will not turn the engine over to restart it.

If you start your engine, disconnect the battery and the engine continues to run, your alternator is still supplying power (so it's OK). If the engine dies the instant you disconnect the battery, the alternator is not putting out useable current and only the battery was providing power to keep the car running and operate all accessories.

Therefor, if your engine continues to run with one battery terminal disconnected, your regulator needs replacing. If the engine quits as soon as you disconnect the battery, your alternator has died. As I'm not familiar with the electrical circuitry of your ZX, please check to see if they made a fuse (or a fusible link) in the charging circuit, which might have blown. If that's all it is, I wouldn't want to raise all this fuss over something small.

If you change out your alternator, do yrslf a favor and spend another $11 for a new regulator, too.

(And of course, look to make sure you haven't dropped your fan belt! If the belt is off the alternator, disregard everything I said above! )

Let us know what you find out?

Frank

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1970 240Z

Thanks to you both. This forum is so valuable. I need to spend more time on it even when I dont have an issue So there is an easy way to find out.it is the voltage reg the alternator looks fairly new and yes ....there is a little fuse box thing near the battery. I'll check those. meanwhile do you have any special place you order these parts from? zcar parts z source etc? Dealer?


so what I am learning is that it may be a voltage regulator or not and

thanks again

Barry

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1983 280ZX 5 speed T-Top Gun metal gray

Yessir, many of us get our partz from MSA (MotorSports Auto) or Black Dragon (if we're really rich), and lately Rock Auto has given our whole Club a 5% discount just because we're all so handsome.

Will someone pleaZe give Barry those three links? My computer is doing weird things today and doesn't want to copy them.

Frank T

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1970 240Z

Here are the links.

MSA: http://www.zcarparts.com/
Black Dragon: http://www.blackdragonauto.com/
Rock Auto: http://www.rockauto.com/

I also find a lot of parts on e-bay but you have to be careful.

Paco Acosta

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'78 280Z

https://www.rockauto.com/catalog/rafram ... =NISSAN&ck[ID]=0&ck[idlist]=0&ck[viewcurrency]=USD&ck[PHP_SESSION_ID]=ardng15pc0fi4qlgo5rgugut95

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1970 240Z

Well Barry, you'll get a laugh out of this!

I started out for the Rochester Z fest weekend early Friday morning. I've been planning on this event for months. I had the whole car prepped for it and I was all packed and had money saved up and had my route all planned, etc etc.
I got 70 miles away from the house and my alternator died! You're the first person I thought of!
It cancelled my whole trip, since I couldn't dare drive around on the battery all weekend. I bought a replacement 90 amp alternator ($90) ystrdy and installed it today. Problem fixed but now, of course, it's too late to go to Rochester. But I thought it was pretty odd that we were just talking about this and it happened to me.

Frank

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1970 240Z

By the way, for experience purposes I'll describe what the car did and how I tested it.

It ran fine for two hours. I check the gauges frequently as I drive and they were always good to go each time I swept them. I drive with my headlamps ON and the ammeter shows a slight Positive charge as I drive. If I turn them off I get a neutral reading on the ammeter.

Leaving a Mass Pike tollbooth I tried to accelerate into another lane. The car sputtered as if it was missing on several cylinders (like you described yours as having bad gasoline), then straightened up and drove OK, altho the exhaust note sounded.....different somehow. I noticed right away that my ammeter was showing slightly Negative (discharge) and knew what had happened. This was the first time this had happened to me since driving cross-country in 1976. I thought of our conversation at that immediate moment.

I drove to a nearby state police barracks and pulled in. Leaving the engine running I disconnected the battery terminal, and the engine died instantly. That indicated the battery, instead of the alternator, was supplying all the electrical current to run the engine. I turned around and drove directly back home, hoping my battery would get me all the way without dying. I left the headlamps and ventilator fan OFF so as not to waste the battery charge on anything but the ignition circuit, directionals and brake lights.

I bought a replacement alternator ystrdy and installed it today (took about an hour). As soon as I fired it up the ammeter went to Positive, showing that I was again charging from the alternator. Hurray!

My alternator differs from yours in that my "regulator" is actually a 3-diode board inside the alternator body. Diodes only allow current to run in one direction (when they work) and they do the job of a regulator on my car. When I buy a new alternator, I am also replacing the 'regulator' along with it.

Frank

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1970 240Z

Before I sold my 280ZX in May, I had bought a new, rebuilt AC/Delco alternator on EBAY for about $50. Figured the original would crash sooner or later and the replacement part could be getting scarce. Sold the car before I ever needed it, and the spare alternator went to the new owner. Whatever you determine the fault to be, I would pick up a new alternator while they are still easy to come by. I found that the correct part changed frequently from year to year, so they may become scarce. By the by, the regulator was in the alternator itself in the '80 model year.

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1980 280ZX 2+2
2003 350z Touring
2005 350Z Touring - Silverstone Gray
CT plate PHILSZ