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All lights are dim, brighten when I rev [UPDATE] Alternator not charging

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JTCN    0

UPDATE: After completing the install my alternator isn't charging the battery. Please see the post at the bottom of the page

 

So I have a '75 280z and recently I've noticed my headlights get brighter when I rev the car. (Both in neutral at stand still and in motion)

I also noticed that my dash lights and interior lights get brighter as well.

The headlights are also very dim whether or not the car is revving or not, revving only brightens them a little and overall they're still dim.

The A/C fan also gets louder and blows harder when revving.

 

So somehow all of these problems are connected to something and I'm at a loss on what to do next.

I've been reading a lot about this and my best guess is there's a problem with the grounds.

If so, where are the grounds located?

 

My problem isn't with the lights/fan getting brighter, but a possible problem with low voltage getting to these systems at idle (or in general)

 

What do you guys think could be the source of all this?

 

Sorry for the barrage of questions but I'm new to electrical gremlins and it's all especially confusing to me.

Thanks for any help

Edited by JTCN

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Zetsaz    4

If they're all working properly, but get dim, more than likely it's your voltage regulator or alternator going bad. Or just as likely it's not strong enough to keep up with everything at once. Alternators are rated by max amps, at idle they're noticeably lower. 

 

Look into doing a later model ZX, or turbo ZX, alternator swap. Or look into using a GM unit. The ZX ones only require a couple wires to be spliced and they give you the security of a more modern, internally regulated, unit as opposed to the units your 75 and my 76 use. The voltage regulators had a tendency to fail prematurely anyway, so it's a great upgrade, especially if you plan on running any sort of more modern audio or upgraded headlights in the future.

 

http://atlanticz.ca/zclub/techtips/alternatorswap/index.html

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JTCN    0

Take the car to Autozone or Oreily's etc and they will check the alternator and battery for free. Then go from there.

 

Also, a loose fan belt can cause those same symptoms.

I've actually been having problems with the alternator belt slipping, every now and then I hear it squeak.

It used to be a lot worse. Squealed the entire time until i tightened it but I think the belt is stretched, so I'm sure I will replace that soon.

In the mean time tomorrow I'll tighten it as much as I can again and see if it fixes the light issue.

I have a feeling it's something more severe though.

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JTCN    0

If they're all working properly, but get dim, more than likely it's your voltage regulator or alternator going bad. Or just as likely it's not strong enough to keep up with everything at once. Alternators are rated by max amps, at idle they're noticeably lower. 

 

Look into doing a later model ZX, or turbo ZX, alternator swap. Or look into using a GM unit. The ZX ones only require a couple wires to be spliced and they give you the security of a more modern, internally regulated, unit as opposed to the units your 75 and my 76 use. The voltage regulators had a tendency to fail prematurely anyway, so it's a great upgrade, especially if you plan on running any sort of more modern audio or upgraded headlights in the future.

 

http://atlanticz.ca/zclub/techtips/alternatorswap/index.html

Thanks, the symptoms of a failing voltage regulator definitely line up with the problems I'm having.

Just found a guide for the ZX alternator swap, do I have to pull one from a junkyard or can I buy a brand name replacement? (Like this one: http://www.ebay.com/itm/Alternator-ACDELCO-PRO-334-1649-Reman-fits-81-83-Nissan-280ZX-2-8L-L6-/331625213876?hash=item4d36672fb4:g:7-UAAOSwPcVV2eDg&vxp=mtr)

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NewZed    56

1975 still has the Ammeter so your simplest quickest check of a failed VR is to put a meter on the battery terminals and rev the engine.  If you get 16 or over, that's bad.  The complete, thorough test procedure is shown in the FSM.  

 

Whatever path you choose, owning a good multimeter is almost mandatory for working on these cars.

 

You can just go to the parts store and get a 1982 280ZX alternator and you'll be fine, if you decide to do the swap.

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JTCN    0

Alright so I did a test on the battery earlier.

I got 12.5 with the car off.

Around 14.8 with the car running and not charging.

When I revved at steady 2000 rpm it was hitting 16 volts.

The readings were also pretty sporadic.

 

Just ordered a ZX alternator and fan belt, hopefully that fixes everything.

I'm going by this guide: http://atlanticz.ca/zclub/techtips/alternatorswap/index.html

 

I'm banking on this fixing my problems, I really believe it's the voltage regulator considering all the common troubles people have with it.

Even if this doesn't work at least it's an upgrade and 1 less thing to worry about.

 

Edit: Got a few numbers mixed up, corrected them

Edited by JTCN

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JTCN    0

UPDATE: My alternator and fan belt came in today so I started and completed the project.

Unfortunately after doing all of the steps in the swap guide, my alternator isn't charging the battery.

With the car off the battery had 12.5v

I turned it on (no lights/accessories) and it was around 12.4v

With lights and fan on highest speed it was 12v. And the fan was hardly blowing on its highest speed.

 

All of the wires for the 1975 year in the guide were the right color on my car, so I crimped the Green/Red wire to the White/Black wire.

Then I crimped White to Yellow.

 

The rest of the wires (Green and Black) I taped up the ends and left them dangling.

I think I did the wiring correctly, but I figured I'd post how I did it anyway.

 

For the alternator wiring I connected battery, earth, and the "T" connector.

But I found a strange blue wire in my battery connector for the alternator.

I think it connected to this thing on the back of the alternator. (Not my pic but it shows where it connects on the original alternator). http://img.photobucket.com/albums/v337/cd1105/IMG00215-20130127-1535_zps87ef6ea3.jpg

My old alternator had the blue wire plugged into that thing but it broke off just from me touching it.

My new alternator has one of those cylinder-shaped things on it but its connected to a bolt on the alternator itself. (Sorry I don't know what the things called lol)

 

So for my first question, do I need to connect this blue wire somewhere? Could that be why it isn't charging?

Here's an album I just made so you guys can see some pictures of it all. http://imgur.com/a/gM5pj

If you guys see anything in these pics that even MIGHT be a problem, please let me know.

Also If you guys want some more pics I'll go out and take some.

Edited by JTCN

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