Alternator follies

[Malleus]

I have an OEM Denso 80A alternator (2007 vintage), which appears to be shirking its duties charging the battery (my daughter calls me at lunch and tells me her truck won't start - days into the troubleshooting I get the pearl of wisdom, "Oh yeah, that red light came on while I was driving").

Perusing the bowels of the charging system service section, I get this tidbit:

Now, here is the offending part (or rather the posterior of it):

Nowhere in any documentation I have found is the "F" terminal identified (the "B" terminal is nicely embossed on the rear shell). For anyone in the know, may I assume that I'm pointing, with my pointy arrow, at the "F" (field) terminal?

And may I further assume that I can, with some bent type tool, as pictured above, connect the two adjacent screws and ground the terminal?

I don't have any photos of the last one I rebuilt, because I've never actually checked an alternator before; I just always assumed they need to be rebuilt and rebuilt them, but from memory, I think this post is the mounting stud for the regulator. (Why am I doing it now, you ask? I really have no idea.)

Thanks for playing along at home, and thanks very much to anyone who has the answer to tonight's trivia question.

 

[Malleus]

Just for laughs, I looked up the circuit and got this insight:

There's the "B" terminal, in all its glory, but, sadly, no "F" buddy.

 

[Malleus]

I'm starting to get the idea, looking through these documents, that Toyota only intended knowledgeable persons to repair their vehicles.

 

[cahill]

Looking at the first photo of the FSM you posted, the L shaped tool looks more like it is centered in the back of the alternator and is supposed to be inserted into a recess. Could terminal F be in the hole on that "D" shaped protrusion of the housing in the center that is stamped "ND"?

I am not a "knowledgeable person" so take my question as just a question

 

[Malleus]

Nope, there's supposed to be a rubber plug there (I think it's a tooling hole). It didn't make the trip. Good thought, though. I'd tend to think the terminal has to be exposed, which is why I "think" it's the screw I'm pointing at; everything under the cover is spinning when it's running.

 

[ToyotaMatt]

I have an OEM Denso 80A alternator (2007 vintage), which appears to be shirking its duties charging the battery (my daughter calls me at lunch and tells me her truck won't start - days into the troubleshooting I get the pearl of wisdom, "Oh yeah, that red light came on while I was driving").

Perusing the bowels of the charging system service section, I get this tidbit:
View attachment 3752866
Now, here is the offending part (or rather the posterior of it):
View attachment 3752868

Nowhere in any documentation I have found is the "F" terminal identified (the "B" terminal is nicely embossed on the rear shell). For anyone in the know, may I assume that I'm pointing, with my pointy arrow, at the "F" (field) terminal?

And may I further assume that I can, with some bent type tool, as pictured above, connect the two adjacent screws and ground the terminal?

I don't have any photos of the last one I rebuilt, because I've never actually checked an alternator before; I just always assumed they need to be rebuilt and rebuilt them, but from memory, I think this post is the mounting stud for the regulator. (Why am I doing it now, you ask? I really have no idea.)

Thanks for playing along at home, and thanks very much to anyone who has the answer to tonight's trivia question.

.
that particular FSM step by step's in the confirm and verify process is what i will term " Full Fielding " , this ensures that when the alternator is pumping out the most possible Direct Current AMPs it is capable of , such as you left your FOG / AUX lamps on after coming home late , then noticed them still ON that next morning ....

- the lamps sucked the Battery / batteries down to a Low enough level to still be ON , but when you try cracking your engine in the Ign. KEY START position , you would only hear the starter click click one time and all the cluster meter illumination goes dim at the same time ..

this specific scenario i outline above means as soon as you your portable Jump-Box or another vehicle and battery cables as they rev there engine at a higher RPM to get your 80 to turn over just enough to fire its engine up . you would then remove the portable jump box and or battery car to car cables right away .....

it this moment your 80's alternator is not only suppling all the on-board electrical system parts there needed Power and there subsequent current draw in a " On-Demand " as needed bases , but also re-charging that now 90% dead battery back to its proper fully charged state of readiness that it has ....

this is when the voltage regulator regulates and prevents the alternator from pumping out too many AMPs and at too high a DC voltage over the stated spec's in the FSM ( example 14.8 Volts ) this is it's controlled Full Field mode ....
F = Field
E = Earth
N= Neutral



the TOYOTA OEM True Start group 27 & 27F series batteries are as follows :

Group 27 : 00544-27060-675 has 675 CCA cold cranking amps
Group 27F : 00544-27F60-710 has 710 CCA cold cranking amps
Both have the highest reserve capacity of any other TOYOTA battery group / the smaller ones 24 , 24F , 35 , 24 , etc

.

​

.

 

[Malleus]

Yes, but which terminal is the "F" terminal?

 

[smritte]

Gawd this brings back memories. Last time I did this was mid 80's.
I haven't done this to one of our alternators but, terminal "F" has always been a small hole in the back and not an actual terminal. The regulator has a tab on its side. You would poke a paperclip in and connect the tab to the alternator housing. Full fielding pretty much went away with the advent of computers. This is due to the voltage that can be produced. Looking at the SM picture you posted, the hole looks like its about an inch out from the center. This is the area I would find the spot. You may be able to see a shiny tab through the hole.

If you do this, only at idle. Reaching back, I think I saw 16 odd volts when I did these.

By the way, "full fielding" is how I use to build alternator welding systems. I am able to produce about 100 volts at about 1800 rpm to power a small grinder or drill. Obviously the vehicle is isolated from the alternator.

 

[TomH]

Following what @smritte said and looking at the picture in the manual, F looks to be next to the cooling fins on the voltage requlator.

I found this on some alternator site.

8090-4428 *NEW* Alternator Regulator for Denso Alternators S-IG-L

8090-4458 *NEW* Alternator Regulator for Denso Alternators S-IG-L 126000-1960, 126000-2050, 126000-2200, 27700-50020, 27700-50030, 27700-62020, IN453, 8090-4428, 230-52091, AND6082 Nippondenso

smithcoelectric.com

 

[Malleus]

Thanks to both @smritte and @TomH for their insight.

I spend some time to day cleaning the offending alternator, and, comparing it to a rebuild candidate I had on the shelf:

As you can see from the photo, the hole in the rear cover does in fact line up with the terminal on the voltage regulator.

Unfortunately, both alternators had bad diodes in the rectifiers, so although I have a very clean alternator, it still does not work. Also unfortunately, I found, looking back through my records, that I went through this alternator in February of 2022, to clean it and replace the brushes. Everything checked out then (except the brushes, which I replaced).

That regulator price almost looks too good to be true:

Toyota's price is twice that. Ouch. and the rectifier, which I also need:

That's the price of a rebuilt alternator. Of course, not from Toyota.

 

[Malleus]

Thanks to @TomH for the parts source. I usually use Alternator and Starter Parts Wholesale, but lately they've been unsatisfying in their parts options (they have a regulator listed, but no rectifier), and they don't offer kits anymore, which is annoying.
I'm going to give them a try and see how long the parts last. With shipping, it was about what Rock Auto wants for a rebuilt AC Delco version (without shipping and less the core charge). Ugh.

I'm not sure why I make the effort to rebuild these things.

 

[cahill]

I'm not sure why I make the effort to rebuild these things.

Mabye so that people like me on the other side of the internet can learn from you . I think this is the 1st thread on mud that I have seen asking about this. If it is, that is quite an accomplishment

 

[jonheld]

Thanks to @TomH for the parts source. I usually use Alternator and Starter Parts Wholesale, but lately they've been unsatisfying in their parts options (they have a regulator listed, but no rectifier), and they don't offer kits anymore, which is annoying.
I'm going to give them a try and see how long the parts last. With shipping, it was about what Rock Auto wants for a rebuilt AC Delco version (without shipping and less the core charge). Ugh.

I'm not sure why I make the effort to rebuild these things.

For these questions, I would reach out to Cam Mosley (www.mosleymotors.com). At one point he was rebuilding and reconditioning Land Cruiser alternators for all years. I have one of his last rebuilt units sitting on a shelf for my LX450. Sadly, he stopped doing this, but I would bet he has a parts resource.

 

[BILT4ME]

Thanks to @TomH for the parts source. I usually use Alternator and Starter Parts Wholesale, but lately they've been unsatisfying in their parts options (they have a regulator listed, but no rectifier), and they don't offer kits anymore, which is annoying.
I'm going to give them a try and see how long the parts last. With shipping, it was about what Rock Auto wants for a rebuilt AC Delco version (without shipping and less the core charge). Ugh.

I'm not sure why I make the effort to rebuild these things.

A rebuilt alternator from Toyota is $180. Why waste time trying to rebuild it when you could have had it installed and running already?

 

[Malleus]

My point exactly. I'm a glutton for punishment.