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Going crazy here, charging issue


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1976  280z coupe changed battery (it was bad), voltage regulator, belt and alternator (which tested bad). The car still fails to charge, I am reading about 12.6 under no load and about 12.3 or 12.4 under load. Car is Still hesitating and bogging at stops. Any thoughts on what I should look for, maybe bad wiring?

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Check your grounds. Make sure your connections are not corroded. Also check your wiring to see if they are brittle and hard. If so, you might have to change out those wires. Those brittle wires might be frail and not making good conductivity.

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  • 1 month later...

Lorenzo, sorry for the late post reply, hopefully you have fixed the issue by now, but just in case you are still hunting for the trouble, I had a charging issue on my '73 very much as you are describing, and it turned out to be a corroded wire in my VR connector. It looked just fine, and I had plugged and unplugged that connector maybe 1/2 dozen times, but it wasn't until I really got in to every connector, cleaning out all the debris and crap that collects in those things, that I discovered the yellow wire was not actually connected! I purchased a new connector from http://vintageconnections.com/ and rebuilt that connection. Everything works great now. Good Luck!

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Are the no charge light illuminated and the Brake warning light on...even with the handbrake released? If so check out the following. It's a weird one....

 

Fuse block. Lower right hand corner. There is a fuse marked 1 amp for Floor Temp lamp. If this fuse is blown you will get a no charge situation.

 

Thing is this circuit is used for non-Catalyst cars ( Canadian and Federal models )  as well as Catalytic( California )  models. This circuit also ties in with the Brake check relay and the Charging relay located inside the V/Reg. If this fuse is blown.... no chargy.

 

Another point. The fuse amperage rating seems to be wrong. No way is it a 1amp. I have a 10 amp fuse in there and it would occasionally blow when the V/Reg acted up. A 1 amp fuse blew as soon as I inserted it. 

 

Picture of 1976 Fuse cover. Fuse in question is in lower right corner.

 

2001388.jpg

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^ Yep.. I recently installed a 1985 Maxima  300ZX ( Mitsubishi 70 amp. ) IR alternator and Voltage is much more stable now. Idle output amperage on these newer alternators is increased substantially over the earlier models. 14.35 Volts at idle and 14.55 volts at 2,000 rpm. Rock steady!!

 

I can have lights, wipers, stereo and defrost on full blast and no drop in Voltage at idle any more. Even the previous 60 amp 280Z alternator ( External Reg ) couldn't mange that. . I feel much more confident taking the 280Z on long trips now.

Edited by Chickenman
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  • 2 weeks later...

Are the no charge light illuminated and the Brake warning light on...even with the handbrake released? If so check out the following. It's a weird one....

 

Fuse block. Lower right hand corner. There is a fuse marked 1 amp for Floor Temp lamp. If this fuse is blown you will get a no charge situation.

 

Thing is this circuit is used for non-Catalyst cars ( Canadian and Federal models )  as well as Catalytic( California )  models. This circuit also ties in with the Brake check relay and the Charging relay located inside the V/Reg. If this fuse is blown.... no chargy.

 

Another point. The fuse amperage rating seems to be wrong. No way is it a 1amp. I have a 10 amp fuse in there and it would occasionally blow when the V/Reg acted up. A 1 amp fuse blew as soon as I inserted it. 

 

Picture of 1976 Fuse cover. Fuse in question is in lower right corner.

 

2001388.jpg

 

I have been away from the car for a bit and it is still not charging correctly. I do not have a Floor Temp fuse in my car, that slot is empty.

 

 

post-2274-0-82507300-1475350857_thumb.jpg

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^ Yep.. I recently installed a 1985 Maxima ( Mitsubishi 70 amp. ) IR alternator and Voltage is much more stable now. Idle output amperage on these newer alternators is increased substantially over the earlier models. 14.35 Volts at idle and 14.55 volts at 2,000 rpm. Rock steady!!

 

I can have lights, wipers, stereo and defrost on full blast and no drop in Voltage at idle any more. Even the previous 60 amp 280Z alternator ( External Reg ) couldn't mange that. . I feel much more confident taking the 280Z on long trips now.

 

 

Chickenman, does that alternator require any mods to fit in the same spot as the original alternator?

Edited by lorenzo
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I had a ton of charging issues with my 75. I ended up just switching to a 280zx alternator and rewired how the write-up stated. Problem solved for 3 years now.

 

 

Grillhands, did you use the rewiring write-up from Atantic Z? That site is no longer working for some reason.

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Here you go.  This wayback machine site is pretty crazy - https://web.archive.org/web/20160307132855if_/http://atlanticz.ca/zclub/techtips/alternatorswap/index.html

 

On a 76 you'll probably have a problem with the brake check warning lamp relay staying on and draining your battery.  You can just disconnect while you figure out a way to get it power only when the engine is running.  It's under the passenger seat.  You'll hear it click when you reconnect the battery.

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Chickenman, does that alternator require any mods to fit in the same spot as the original alternator?

Bolts right in. All mounting points are the same as a Z and uses the same belt.

 

Terminal on back of alternator is different though. A lot of Mazda products use the same connector. Miata's, Proteges, Mini Vans etc. I grabbed one from the local Pick a Part.. $2

 

You can also get them new a repair pigtail on E-Bay.

 

http://www.ebay.com/itm/REPAIR-PLUG-HARNESS-2-WIRE-PIGTAIL-Fits-MAZDA-323-626-Miata-MX-6-RX-7-Protege-/301227362561?hash=item46228cc901:g:TIEAAOSw3ydVlIyo&vxp=mtr

 

s-l1600.jpg

 

I used the Z Car creations wiring artcle. Works just fine.

 

http://www.zcarcreations.com/howto/voltreg.htm

 

Edit. Just noticed I said 1985 Maxima in my post. I actually used a 1985 300ZX 70 amp alternator. The 85 300ZX 70 amp alternator has a single groove pulley.

 

The 85 Maxima has a serpentine pulley that you have to swap over. The Maxima alternators are available in 80 and 90 amp versions though, which is why they probably have to use a serpentine belt. . Rock Auto has some great deals. The Remy alternators at Rock Auto are good quality.

Edited by Chickenman
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Bolts right in. All mounting points are the same as a Z and uses the same belt.

 

Terminal on back of alternator is different though. A lot of Mazda products use the same connector. Miata's, Proteges, Mini Vans etc. I grabbed one from the local Pick a Part.. $2

 

You can also get them new a repair pigtail on E-Bay.

 

http://www.ebay.com/itm/REPAIR-PLUG-HARNESS-2-WIRE-PIGTAIL-Fits-MAZDA-323-626-Miata-MX-6-RX-7-Protege-/301227362561?hash=item46228cc901:g:TIEAAOSw3ydVlIyo&vxp=mtr

 

s-l1600.jpg

 

I used the Z Car creations wiring artcle. Works just fine.

 

http://www.zcarcreations.com/howto/voltreg.htm

 

Edit. Just noticed I said 1985 Maxima in my post. I actually used a 1985 300ZX 70 amp alternator. The 85 300ZX 70 amp alternator has a single groove pulley.

 

The 85 Maxima has a serpentine pulley that you have to swap over. The Maxima alternators are available in 80 and 90 amp versions though, which is why they probably have to use a serpentine belt. . Rock Auto has some great deals. The Remy alternators at Rock Auto are good quality.

 

Thank you for this detailed write-up chickenman!

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Here you go.  This wayback machine site is pretty crazy - https://web.archive.org/web/20160307132855if_/http://atlanticz.ca/zclub/techtips/alternatorswap/index.html

 

On a 76 you'll probably have a problem with the brake check warning lamp relay staying on and draining your battery.  You can just disconnect while you figure out a way to get it power only when the engine is running.  It's under the passenger seat.  You'll hear it click when you reconnect the battery.

 

NewZed, thank you for the link. I will look into that connection under the passenger seat. This seems to be a strange one. Would this continue to be a concern if I were to do the swap with a ZX alternator?

Edited by lorenzo
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It's not the alternator itself it's the wire used as the S (sense) wire.  The atlanticz scheme connects the relay wire to constant power.  The zcreations scheme changes the way the relay gets its power too but doesn't leave it on all the time.  When I tried it the light didn't work anymore.  Both schemes will get the alternator working though.  Just beware of the relay and what it does.  If it works the way you like it, use it.  It's described in the Meters and Gauges section of the Body Electrical chapter.  Has its own complete writeup.

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  • 3 weeks later...

Just wanted to thank everyone who contributed to this thread and let everyone know that I have finally solved the problem! 

 

Used a1983 280zx alternator (AC Delco) remanufactured          

 

Wiring as recommended by Zcarcreations        

 

Charge light seems to be working well and turns off after starting it. Getting 14.55 volts under load. I will not get much chance to drive it though as winter is just around the corner :(                                                                                                                                                                      

Edited by lorenzo
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