Help me hook up this alternator so I don't fry my ride

[josh817]

Alright guys I've been searching and trying to chat with some members about my alternator not charging issue. Let me just get down to the dirty details.

 

-1971 521 Truck

-I rewired the truck using most of the stock wiring harness

-No I do not have a voltage regulator wired in

-I have a 90 amp internally regulated alternator "single wire"

-Can't get the thing to charge for the life of me

-I have the WHITE/RED IGN LIGHT wire from the dash going to the left side of the 3 prong plug

-I have a SWITCHED 12V going to the right side of the 3 prong plug

-The light turns on when motor isn't running, goes off when motor is running

-The alternator case is grounded well

-I only read 12.4V at the battery and no change when I rev the motor, however the voltage creeps up slowly to maybe 12.6V if I'm lucky

 

Here is a quick reference to how I have my setup wired:

 

I need some brain power because I'm trying to decipher between a shitty dead brand new alternator or wrong wiring. My search has yielded me nothing. Many different situations; someone is running external reg., someone has a 620 with different wiring, someone has the "T" connection and not the type I have, someone has this that or the other. I can't pinpoint an answer and I need an answer pretty badly because my old daily driver is selling in 3 days. I can't be jumping a dead battery every day (its not dead yet but I'm sure it will be).

 

Second question. With what you see now, concerning the wires I have, If I buy a 50 amp 720 internally regulated alternator, do I simply hook up my gauge light and switched 12v to the "T" connection? If so, where does the switched 12v go and by obvious means of deduction I will hook the dash light to the other.

 

Thanks for the help, I greatly appreciate it guys.

[banzai510(hainz)]

wheres the ground wire to the Alternator? the one from the truck that should bolt to the alternator?

 

when you go internal reg alt you need to short the blk/wht with the red/wht and wht with the yellow.

 

the Dime Quarterly has this in the electrical section

 

or GGZilla Datzenmike or other can ppost for you as i cannot pst my photos on here anymore.

[H5WAGON]

"I'm trying to decipher between a shitty dead brand new alternator or wrong wiring."

Is it brand new? Tested?

 

 

"I can't be jumping a dead battery every day (its not dead yet but I'm sure it will be)."

Does the battery die? or ? Does it start and run? you said it reads 12.4-12.6.......Does it ever go lower?

 

 

"-No I do not have a voltage regulator wired in"

And you did the required mod?

 

 

 

Since this is a 90amp......does it not need to push so many volts into the batt.....? Electrical expert?

[josh817]

when you go internal reg alt you need to short the blk/wht with the red/wht and wht with the yellow.

No sir I didn't do that. That is why I posted this thread, because my situation is different then most others. I literally do not have those wires. If you look at a wiring diagram for a 521, and you cut out all the voltage reg/alternator/battery shit. Then add in the simple wiring I showed above, that is what I am running. I don't see a problem in what I did because the voltage reg powered the IGN light, reverse light switch it appears, and sent regulated voltage to the fuse box if I remember, I don't have it in front of me right now.

 

I'm not using reverse lights and up until last night I didn't have the W/R IGN Light wire hooked to anything. I simply have the output of the alt. to the starter post, which branches that 12v charge to the fuse box and to the battery. The alternator case is a very good ground. I can't locate another post on it or any threaded hole where a post would have been. Is the ground on an alternator isolated like the charging post or does it allow the case to be used as a ground for redundancy?

 

So a long winded answer to your question, no I didn't do any shorting of wires because those wires do not exist in the harness I have.

 

"I'm trying to decipher between a shitty dead brand new alternator or wrong wiring."

Is it brand new? Tested?

Yes it's brand new. My dad bought it for one of our track cars but let me take it for the truck, because I wanted a one wire alternator. No it hasn't been tested as far as I know of. It's about 2 or 3 years old so he's killing me by not knowing any details on the alternator. As you can see from the two pictures I provided, what I have is not exactly like the Nippondenso diagram I provided, however the circular plug it universal I would think, as are the connections.

 

"I can't be jumping a dead battery every day (its not dead yet but I'm sure it will be)."

Does the battery die? or ? Does it start and run? you said it reads 12.4-12.6.......Does it ever go lower?

The battery doesn't, or I should say, hasn't died. I've been driving for about 4 or 5 hours so far, 1 hour worth of headlights on while driving. 12.35V is the lowest charge I have seen with the motor off. When new, it read 12.7v (measuring from the same location). When running, this voltage doesn't change, it was slowly creeping up by .01v increments. When I turn the headlights/highbeams on it goes from 12.4v to around 12.1v which I don't like. I'm running an electric fuel pump too. I would think that the battery would be dead by now if I had a situation however it's a pretty big battery...

 

"-No I do not have a voltage regulator wired in"

And you did the required mod?

I think I answered this in the above paragraph of this post. I didn't do/read of any mod. Unless if what I did on my own, is similar to the said mod you speak of. The wiring diagram I drew in my first post is exactly how I have it. Again, going off my memory without the schematic, the stock external reg hooked up to the alternator with:

-Black ground

-White power

-2 wires to the "T" connectors

-1 wire powering the reverse switch

-1 wire powering the ign light on dash

Cutting this out of my harness (not really cutting, just removed all the wires), I was left with only the W/R coming from pin 9 on the gauge gluster harness, which is what I am using now on the current alternator.

 

Since this is a 90amp......does it not need to push so many volts into the batt.....? Electrical expert?

That's a good point. I will check that when I get home by running the motor and turning EVERYTHING on. Headlights, blower, hazards, wipers, and see what voltage it reads. Perhaps it only maintains a 12v range... and lol I'm not an electrical expert, my dad is but he won't sit down with me.

 

 

EDIT:

Alright Banzai, I've been looking over the resources you provided; this time with my head out of my ass and a full nights worth of sleep.

 

This picture from the link you sent me:

(http://datsun510.com/photopost/showfull.php?photo=124)

 

I did exactly this. The L is going to the dash ign light, as it says to short. The S is going to 12v from the starter. Mine only differs from that because I have mine hooked to a switched and fused 12v source and not to the starter post which is presumably hot all the time. Also the White/Blue wire I do not have (assuming reverse switch). So that clears that up, I guess I did do the proper regulator removal mod. Is it possible that I have my L and S flipped or something, although I doubt it? No smoke, funky smells, any of that chaos occured and as I stated before, the dash light does indeed work.

 

Things for me to check tonight:

-be absolutely sure the alt. is grounded through the case, through a post, whatever

-put as big of a load as I can on the alt. and see what it does

[banzai510(hainz)]

Be honest Im not a Datsun mechanic but I did stay at a Holiday Inn Express one nite!!!!!!

 

I have never done this mod as I still use external alternators. Just seen others do it and 98% of the time it works great.

 

 

Do this first:

I would get the alternator ck out at Napa,O Rileys or where ever and LOAD CK IT also.

 

 

and lol I'm not an electrical expert, my dad is but he won't sit down with me.??

Tell him ,a Mind is a terrible thing to waist and your going to Big Brothers and Big Sisters for Help

[josh817]

I suppose that's just how he is. He gets so involved with Triumphs and Jags, but acts clueless when I ask questions for my Datsun's. He'll act like it's some foreign mystery vehicle.... a lot of the stuff is the same concept. Luckily not the wiring. Yay for no Lucas. haha

 

Atleast with the Z he came over to the house to help me get it started, tune the DCOE's, and set timing.

[banzai510(hainz)]

He gets so involved with Triumphs and Jags????????

No wonder he doesnt have time for you!!!!!!!

He should be a electrical expert since working on British cars. If he hasnt caught on Fire yet.

 

your close to figuring it out but ck the alternator.

but I know the white/red and big white wire all loop to the fusable link which is positive all the time.

 

i think olddatsuns.com has a schemantic on there. but its should be same as the 510 what I have seen from my 521 and my 510 71,72s

[josh817]

I don't know why but he likes to race them and now he has a shop for british race cars and restorations...

 

Hot all the time eh? I'll see what I can do with my switched 12v. I need to stop cutting wires, crimping shit on, cutting again, crimping. I won't have any wire left. lol

 

12v all the time to the Sense terminal won't drain the battery when off? I'll take your word for it and just do it! The easiest way I can think of is just put a ring terminal onto the charge post of the alt. and loop it to the 12v Sense terminal, since the charge post is technically hooked to the battery.

[ggzilla]

Haha that's not a single-wire alternator. There are three wires on it, just like every Datsun alternator. You should hook up a ground wire for relibility (you can ground it through the bracket, but it is not so reliable).

 

In any case your wiring is correct. So it must be a bad alternator. Take it down to Oreillys or Autozone and they will test it for you.

[josh817]

Turned on everything that I possibly could and voltage dropped to 12.1V At idle voltage will creep up. Revved it up to 3000-4000 and the voltage didn't rise.

 

Must be the alternator but hey it will work for me for a week until I get some money to buy a Nissan one. 720 truck I see is a 50 amp for $60 no core. I think that will be good enough for everything to run plus a radio. I don't use any amps or stereo shit.

[banzai510(hainz)]

i would have just ck the alternator anyway

[josh817]

I'll have it checked but either way I'm getting a Nissan unit. My dad let me use this little alternator from the race car under the terms that I replaced it with a similar small one for the BMW. As you can see I don't know much about alternators so I'll save myself the trouble and just give back the one that he wanted. :D

 

And I'll have the new remanned Nissan unit tested when I pick it up at the store!