1st Gen Charging Issue

London Gentleman · Jul 31, 2009

So my truck is a 1980 with a '77 20R, it has a new FEN green alternator, 5 prong regulator. I put the new alternator in and plugged in the wiring in the back, started driving it around, noticed that the battery was getting overcharged. Got a volt meter on it and it was reaching 18 volts, so i got a new regulator, still doing it. Went to highway auto and the guy said that its a problem with the wiring in the plug, same plug but toyota moved around the wires. So i moved the green wire to the F terminal, the yellow to the N terminal and left the white and black wire in the E terminal (stock is green into N, yellow to F, white and black to E). Then I checked the volts again and its at around 12.50ish. So i thought cool, started driving it around. Go to start it one morning and the battery is dead. Jumped the battery, drove it to the gas station, had to jump it again, then drove to the girlfriends place, it started fine then but died on the way home. Had to jump it again to get it home. Checked the volts, 11.50ish. So i moved the wires back to stock in the plug and it went upto 13.50ish but the charge light was on, driving it around and the charge light went off, finally checked it with the light off and its getting 17+ volts. I took the alt in and got it checked, napa says its fine. Switched the regulators(new and old), that didnt do anything. Put a ground wire from alt to battery to see if the ground is bad, didnt do anything. Anybody got any ideas? The thing is pissing me off.

graysquirrel · Jul 31, 2009

I chased this same problem FOREVER. My problem ended up being about half way from the alt to the next plug on the fenderwell the wires had melted and were all touching together. But it was all under the shrink wrap so i didnt see or check it for a long time.

Just something to check:awesomework:

London Gentleman · Jul 31, 2009

Seriously just checked that, no problems there. Guess I keeping following the wires...

London Gentleman · Jul 31, 2009

Also the last time it was getting 17+ volts when I would rev it I would hear a buzzing under the dash, the charge lamp relay is down there but I don't know the significance of that in my situation...

nevada · Jul 31, 2009

we ran into this same problem with a first gen truck. i THINK it was an issue with the regulator....we never did fix it.

we tossed that ****. and got a GM 1wire alt.

London Gentleman · Jul 31, 2009

Unless I got a bad regulator that shouldn't be the issue. The wiring looks good going into it...

nevada · Aug 1, 2009

London Gentleman said:
Unless I got a bad regulator that shouldn't be the issue. The wiring looks good going into it...

our problem was....the regulator, and the alt...just wouldnt work together. something about the wiring changed..or some ****. BUT we could never find the proper reg, and itd never work right.

we used every that was SUPPOSED to go to the truck, but it never worked.

Fordzuki · Aug 1, 2009

Did you have a full charge on the battery when you started it, after putting the new alternator and regulator in? I don't know how similar they are, but a datsun alternator will fry a diode in the alternator if you don't have a full charge when first installing it.

ain'tstuckjustresting · Aug 1, 2009

Also, It's very important to bolt the regulator up before you start the engine. The housing has to be grounded or it will fry itself asap. Seen so many times when guys just plug in the new one and fire it off to see if that was the problem.

Thats why most parts stores wount let you return them. Unless it's Schucks because they don't care either way.

CHOP SHOP · Aug 1, 2009

nevada said:
we ran into this same problem with a first gen truck. i THINK it was an issue with the regulator....we never did fix it.

we tossed that ****. and got a GM 1wire alt.

The 1st gens are a charging POS. Lose that **** and just one wire it.

Every one I have had **** on you and is confusing as hell to TS. **** that ****. Get rid of it and better your rig.

Last one I had would run shitty when the charge light came on too.

I even forgot about my old celica ten years ago had the same **** and it sucked to.

Change it or have fun chasing GHOSTS.

Nothin beats a 37 dollar chevy alternator.:beer:

CHOP SHOP · Aug 1, 2009

ain'tstuckjustresting said:
Also, It's very important to bolt the regulator up before you start the engine. The housing has to be grounded or it will fry itself asap. Seen so many times when guys just plug in the new one and fire it off to see if that was the problem. Thats why most parts stores wount let you return them. Unless it's Schucks because they don't care either way.

See, if its tossed in the trash in favor of a chevy one wire, you dont need to know all these little exclusive dumb dos and donts.

Is there a dance required to make one last more than 3 months even when you do get one to function?:corn:

Theres a reason TOYOTA ditched that **** in 84.:beer:

ain'tstuckjustresting · Aug 1, 2009

Yeah, I think it's the Chicken Dance!

Ever take a Yota alt in and try to get it juiced up to help out with winching and lots of lights? $150 gets you 85a. That's about $35 for a 85a cheby.

London Gentleman · Aug 1, 2009

I'm thinking its the hoopty dance. yeah the regulator was bolted to the fenderwell. apparently thunderbird alts are good, 130 amps, 2 wires. Guess I'm just holding out for Toyota...

ljtoy · Aug 16, 2009

In the past 27 years I've seen some sorry **** towed to my shop. Best one was a 78-79 Toy 2x with a 20R. They put new alternators on it twice, Schucks and Carquest brands. The guy "got used to" driving over to duck hunt in eastern WA, then having the battery "blow-up" on the way back. After 4 years of this it showed up at my door; fix-it was all he said. You have to remember there are 3 - THREE types of charging systems in those production years. Cut to the finish; he had gotten a Celica alternator the first time, replaced it with ANOTHER Celica(maybe) alternator. Both those are not compatabile with that year truck!

Big Trick = if the system is stock ND record the numbers off the starter, regulator and alternator. Next chance you get, call the dealer, sound important, give them your OE number and get a crossreferenced reman number! DONE.

No re-wire, fixed. Cheap parts bite you in the ASS... ALWAYS!

PS-Install two red-top or yellow top Optima batteries. One will be for the winch. Simple! You're worth it, so spend the extra money 'wisely' on your ToY.

London Gentleman · Aug 26, 2009

So a little update, got a GM 1 wire put it in. Its getting 14.6 volts idling, when I rev the motor the volts climb with how much I rev the motor.At 3500 rpm its getting 16.8 volts.... Ideas?

CHOP SHOP · Aug 26, 2009

ljtoy said:
In the past 27 years I've seen some sorry **** towed to my shop. Best one was a 78-79 Toy 2x with a 20R. They put new alternators on it twice, Schucks and Carquest brands. The guy "got used to" driving over to duck hunt in eastern WA, then having the battery "blow-up" on the way back. After 4 years of this it showed up at my door; fix-it was all he said. You have to remember there are 3 - THREE types of charging systems in those production years. Cut to the finish; he had gotten a Celica alternator the first time, replaced it with ANOTHER Celica(maybe) alternator. Both those are not compatabile with that year truck!

Big Trick = if the system is stock ND record the numbers off the starter, regulator and alternator. Next chance you get, call the dealer, sound important, give them your OE number and get a crossreferenced reman number! DONE.

No re-wire, fixed. Cheap parts bite you in the ASS... ALWAYS!

PS-Install two red-top or yellow top Optima batteries. One will be for the winch. Simple! You're worth it, so spend the extra money 'wisely' on your ToY.

I wondered if you knew WTF you were sayin? Then I got to the optima part and realized it was all jibberish!!:kissmyass:

CHOP SHOP · Aug 26, 2009

London Gentleman said:
So a little update, got a GM 1 wire put it in. Its getting 14.6 volts idling, when I rev the motor the volts climb with how much I rev the motor.At 3500 rpm its getting 16.8 volts.... Ideas?

Are you using the toyota gauge as a reference or a voltmeter?

nevada · Aug 26, 2009

sounds like a bad reg. BUT, ive NEVER put a gauge on mine..to see what its doing.

London Gentleman · Aug 26, 2009

Volt meter.

London Gentleman · Sep 17, 2009

My battery is fine, put it in my bros 3rd Gen and its getting 14.51 volts. I don't know what is going on with the stupid truck. I have the charge wire to the battery, the red wire from the plug going to the battery, and the white wire to the yellow wire that hooked up to the oem alt.