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1975 280z New ZX Alternator Won't Charge


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#1 JTCN

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Posted 09 February 2017 - 10:56 AM

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.photobuck...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.



#2 NewZed

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Posted 09 February 2017 - 12:19 PM

"the swap guide,"

Which one?  Provide a link.



#3 JTCN

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Posted 09 February 2017 - 12:22 PM

http://atlanticz.ca/...swap/index.html this one.

#4 NewZed

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Posted 09 February 2017 - 12:31 PM

If L doesn't get power with the key on the alternator won't charge.  Do you have a meter?  Is your ammeter connected?  Have you had the car long?  Did the old external regulator system work?  Why did you decide to do the swap?  Is the alternator body grounded?

 

The thing is called a condenser.  The body is grounded and the wire is connected to the main charging wire.  



#5 JTCN

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Posted 09 February 2017 - 12:37 PM

Yeah I have a meter, I'll check L with it in a minute.
The ammeter is connected. It goes down when I turn accessories on in the car.
I've has the car for a year. Im switching to the internal reg. Because i was hitting 16v while revving the car and I was having dim lighting issues.
I connected the earth wire to the alternator so I think its grounded.
What should I do with that condenser wire? Its just dangling right now.

#6 Greeko

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Posted 09 February 2017 - 12:44 PM

Also, Check the voltage At the alternator when it is running.... If it isnt around 13-14V..you may have a bad alternator or a high resistance short between ground and battery  To check this remove the wire to battery from the alternator and start it up again.



#7 NewZed

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Posted 09 February 2017 - 12:53 PM

The wire connects to the thick charging wire.

 

You should always check your work with a meter if you can.  It will save you a lot of time.  If you don't have battery voltage at the T plug with the key on, work back in the wiring until you find the problem.  The 1975 wiring diagrams will help you also.  The Engine Electrical chapter has small specific diagrams so you don't have to use the big one.



#8 NewZed

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Posted 09 February 2017 - 01:07 PM

 

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

 

1975 doesn't show a blue wire but 1976 does.  Use your meter to find the switched power wire.  You might have 76 colors in your 75.  Nissan changed things on the fly sometimes.

 

And what does "battery connector for the alternator" mean?  Doesn't paint a picture.

Attached Files



#9 JTCN

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Posted 09 February 2017 - 01:13 PM

1975 doesn't show a blue wire but 1976 does.  Use your meter to find the switched power wire.  You might have 76 colors in your 75.  Nissan changed things on the fly sometimes.

 

And what does "battery connector for the alternator" mean?  Doesn't paint a picture.

The blue wire I'm referring to isn't tied into the regulator harness. It's literally coming out the back of the plug for the battery to alternator cable.

This isn't a great pic but you can see it coming out from the rubber boot over the battery cable.It's the yellow wire next to the white/red wire. http://imgur.com/On5jBDJ

 

 

Also, Check the voltage At the alternator when it is running.... If it isnt around 13-14V..you may have a bad alternator or a high resistance short between ground and battery  To check this remove the wire to battery from the alternator and start it up again.

Alright so how do I check the voltage a wire is getting? Do I set the meter to DC 20v and touch both probes to the wire? Sorry for the noob electrical questions.

 

 

The wire connects to the thick charging wire.

 

So... what do I do with it? Is it important?



#10 JTCN

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Posted 09 February 2017 - 01:14 PM

Here's a better pic I found of the blue wire coming out the back of the battery cable. http://img.photobuck...ps87ef6ea3.jpg

Not my pic just one I found on google.


Edited by JTCN, 09 February 2017 - 01:18 PM.


#11 NewZed

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Posted 09 February 2017 - 01:28 PM

That's the condenser.  And the charging wire (withe with red stripe).  The battery cable is the one that goes from the battery to the start lug.  It's big and thick.  Like a cable.

 

Just connect it like it's shown in the picture.  To the BAT terminal.  The wire end of the condenser connects to positive, the body to Earth/ground.  E.  It is there to absorb electrical noise.   Don't leave the blue wire coming out of the harness disconnected because it might short to ground.  Hopefully it hasn't already.

 

Check your fusible links while you're in the engine bay.  To be sure you didn't short something and blow a link.



#12 JTCN

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Posted 09 February 2017 - 01:46 PM

Okay let's get this straight. The blue wire goes to the condenser. When I removed the old alternator the blue wire came off of the condenser. I installed the new alternator and it has a condenser already installed. It's connected to the BAT terminal on the alternator. Now I'm left with this blue condenser wire coming off of the charging wire.

So since I already have a condenser and it's plugged onto the BAT terminal, I don't know what to do with the old condenser wire.

For now I think I'll tape it up and forget about it for a little bit.

 

I'm going to test the voltage going to the "T" connector and charging wire.


Edited by JTCN, 09 February 2017 - 02:01 PM.


#13 JTCN

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Posted 09 February 2017 - 02:19 PM

Just got back from checking the voltage at L on the "T" connector.

0v with the key off and I was getting 12.5 with the key on.

I took the "Charging wire" off the BAT on alternator and tested the charging wire. ( Is this what I was supposed to check on?)  With key off it was getting 12.5v, key on 12.5v, and when the car was running it was getting 11v.

 

Where do I go from here? Could it be the wiring I have done to the voltage regulator harness? I think I got it right but I don't know where else to look.

 

Edit: took a quick pic of what the back of my alternator looks like if anyone was wondering. http://i.imgur.com/fRSOvqZ.jpg


Edited by JTCN, 09 February 2017 - 02:47 PM.


#14 NewZed

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Posted 09 February 2017 - 03:30 PM

We've overlooked one of the basics of most Z and ZX alternators, especially the parts store remans - they don't put out much current at low RPM.  Did you rev the engine and check voltage?  If you have battery voltage at the L terminal (the bottom of the T) the alternator should charge if it's spinning and nothing is drawing it down.  Your battery is getting low, 12.4 means it at about 70% and needs a charge, and it might be drawing all of the current if you're doing your voltage checks at idle RPM.

 

If you give it a rev and it still doesn't charge, have it checked at a parts store.  Parts store remans aren't known for high quality, generally.

 

Your wiring seems right.  It should work.



#15 JTCN

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Posted 09 February 2017 - 05:25 PM

We've overlooked one of the basics of most Z and ZX alternators, especially the parts store remans - they don't put out much current at low RPM.  Did you rev the engine and check voltage?  If you have battery voltage at the L terminal (the bottom of the T) the alternator should charge if it's spinning and nothing is drawing it down.  Your battery is getting low, 12.4 means it at about 70% and needs a charge, and it might be drawing all of the current if you're doing your voltage checks at idle RPM.

 

If you give it a rev and it still doesn't charge, have it checked at a parts store.  Parts store remans aren't known for high quality, generally.

 

Your wiring seems right.  It should work.

Yep I was revvin it pretty good while testing. Gonna check all my connections in the morning to make sure they're real good and test it one last time.

If that doesn't work I'll pull the alternator out and drive to autozone and get it tested. Maybe I'll get lucky.

 

Thanks for the help everyone, I'll update this post with what they say and what I'll do after that.



#16 Zetsaz

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Posted 09 February 2017 - 09:44 PM

If you happen to read my build thread I mention a very poor experience with Autozone testing my alternator on an older Maxima that was my daily, caused me a lot of grief until I bought a high quality multimeter and tested things myself only to find out the alternator was definitely bad. Wasted a lot of time chasing other potential problems and had to have the car pushed across a bridge by an officer and later had to be towed when I thought I had fixed things.

 

Needless to say I wouldn't recommend getting anything electrical tested at Autozone. I've trusted NAPA more lately. 



#17 JTCN

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Posted 10 February 2017 - 12:46 AM

If you happen to read my build thread I mention a very poor experience with Autozone testing my alternator on an older Maxima that was my daily, caused me a lot of grief until I bought a high quality multimeter and tested things myself only to find out the alternator was definitely bad. Wasted a lot of time chasing other potential problems and had to have the car pushed across a bridge by an officer and later had to be towed when I thought I had fixed things.

 

Needless to say I wouldn't recommend getting anything electrical tested at Autozone. I've trusted NAPA more lately. 

Yeah I'm sure I can't expect good quality from autozone, but I'm just looking for a confirmation if I just got a dud alternator or there's a problem with my connections.

Would honestly be relieved if the alternator is faulty, at least then I know I didn't screw anything up.



#18 softopz

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Posted 10 February 2017 - 04:58 AM

So test the alternator with a multimeter like Greeko Mentioned. And work back


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#19 Zetsaz

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Posted 10 February 2017 - 12:07 PM

So test the alternator with a multimeter like Greeko Mentioned. And work back

 

This. I didn't buy my alternator from them. They gave me a false positive when they tested the one I had. That's why I'm saying test it with a multimeter or have it tested somewhere else. 



#20 JTCN

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Posted 10 February 2017 - 01:55 PM

Just got back from running all over town and getting the alternator tested.

I took it to autozone and it passed every test. shit.

I'm gonna try re-wiring the splices I made in case it was a crappy connection.

How do I test the voltage output at the alternator? I know it's not reaching the battery if it is charging, so I can't measure it at the battery terminals.






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