Alternator question (1 Viewer)

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Joined
Dec 22, 2011
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Location
Charleston, SC
I bought a rebuilt alternator a while back and just dropped it into my '87 FJ60. My old alternator was pretty old, but working... with recent down time I figured I would drop the new one in. CHARGE light came on inside the truck after installation. Voltage on the dash gauge was low. I put the old alternator back in and the light went off, voltage back up.

After all of that I noticed that my new, rebuilt alternator did not have this small connecting wire with the rubber cap on the back of the alternator (see pic stolen from the web). I'm going to take that wire off the old one and put it on the new one, hoping that was the issue. Just wondering what that wire is for. I assume it's necessary and hopefully the cause of my issue.

Thanks for any advice.

coolfj40_2270_253164601.jpg
 
The wire in your picture goes to a suppression capacitor (the cylindrical device that gets its ground through the body). The capacitor won't make your alternator work, it just suppresses RFI from bothering your old AM radio.

You have some other issue going on... I assume you wired the L and S (the green connector in the picture above) correctly? One is the sense to measure the battery voltage (should go to the battery +) and the other is the field excitation that goes to your Charge Warning light bulb. The bulb provides a resistive path to provide some field current to 'boot' up the alternator, once it is running it will output voltage such that the charge bulb has nominal 14V on both sides and so it goes out.

L & S connector implies you are using an internally regulated alternator.

cheers,
george.
 
Last edited:
Thanks a lot George, I appreciate you taking the time to explain that. Much appreciated!
 
Your new Alt has the voltage regulator, or you swapped it over ? (gotta ask)
 
Yes, it came with the voltage regulator. Really not sure why it isn't working. I know it's wired correctly since the old one works just fine. I'm thinking it's just a bad rebuild. I reached out to the guy I bought it from to see if I can send it back and have him take a look at it.
 
The wire in your picture goes to a suppression capacitor (the cylindrical device that gets its ground through the body). The capacitor won't make your alternator work, it just suppresses RFI from bothering your old AM radio.

You have some other issue going on... I assume you wired the L and S (the green connector in the picture above) correctly? One is the sense to measure the battery voltage (should go to the battery +) and the other is the field excitation that goes to your Charge Warning light bulb. The bulb provides a resistive path to provide some field current to 'boot' up the alternator, once it is running it will output voltage such that the charge bulb has nominal 14V on both sides and so it goes out.

L & S connector implies you are using an internally regulated alternator.

cheers,
george.


I bought a rebuilt alternator a while back and just dropped it into my '87 FJ60. My old alternator was pretty old, but working... with recent down time I figured I would drop the new one in. CHARGE light came on inside the truck after installation. Voltage on the dash gauge was low. I put the old alternator back in and the light went off, voltage back up.

After all of that I noticed that my new, rebuilt alternator did not have this small connecting wire with the rubber cap on the back of the alternator (see pic stolen from the web). I'm going to take that wire off the old one and put it on the new one, hoping that was the issue. Just wondering what that wire is for. I assume it's necessary and hopefully the cause of my issue.

Thanks for any advice.

View attachment 2278894
The wire in your picture goes to a suppression capacitor (the cylindrical device that gets its ground through the body). The capacitor won't make your alternator work, it just suppresses RFI from bothering your old AM radio.

You have some other issue going on... I assume you wired the L and S (the green connector in the picture above) correctly? One is the sense to measure the battery voltage (should go to the battery +) and the other is the field excitation that goes to your Charge Warning light bulb. The bulb provides a resistive path to provide some field current to 'boot' up the alternator, once it is running it will output voltage such that the charge bulb has nominal 14V on both sides and so it goes out.

L & S connector implies you are using an internally regulated alternator.

cheers,
george.

H







My alternator went in my 85 Landcruiser. There's a Denso 27700-38100-84 one in there right now.
I can't seem to find how many amps it is.
Anybody know?

Also, they don't make these anymore, any suggestions on a reliable replacement?

Many thanks!
 
I just put this one in my 84 FJ60 and aside from having to swap my old single row pulley over it fit fine and works well.

7A873AE8-072A-4F26-9166-74CE1B9EAB91.jpeg


F8B3A53D-7B16-4394-B644-69A7A789194A.jpeg


08AE2C62-5DEA-4957-8F67-0A7F49CA8DD9.jpeg
 
I just put this one in my 84 FJ60 and aside from having to swap my old single row pulley over it fit fine and works well.

View attachment 2300823

View attachment 2300825

View attachment 2300826


For Those who go this route or any other NON-NipponDenso like this DELCO unit that came with a 2 groove V belt pulley

i offer and have in-stock OEM TOYOTA FJ60 / late Model FJ40

NEW in the Box Alternator Pulleys & the new updated Flange style Nut , takes the place of the old HEX nut and spring washer set up ..........

our 27020-61011 Units need the best care possible and the correct
oem COG belt Pulley is a good place to start ..........


also have Tensioner Drive belts kits , these are made from 100 Toyota genuine parts sourced abroad .......

Please see these Links below .......
















1589188107410.png
 
You know you really don't need to "hide" the Denso part number for the pulley on the box.

It's readily visible and cast into the pulley itself. :lol: :meh:
 

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