Please help me troubleshoot my charging system

[Schroedinger]

1986 FJ60 that I got a few weeks ago. Going through it and un-effing a bunch of stuff done by previous owners.

One of the major ones- when running, the battery is charging at 17+ volts. The meter on the dash is pegged, and there is some water on top of the battery that indicates boiling. I'm immediately suspicious of the voltage regulator.

Here is the alternator- looks recently replaced and based on the part number, it looks like it's a remanufactured FJ40 unit from Cruiser Corps.

Here is a pic of the wiring on the back... I have no idea what's going on here and the giant ball of electrical tape is giving me a bad feeling. There's nothing at all on the red terminal, it looks like a spade connector is jammed into the harness plug, and B+ is going out to the harness through a wire that's no more than 12 gauge.

I consulted the factory service manual, but it's clear as mud on this topic. Am I guessing correctly that the original FJ60 alternator was internally regulated, and this FJ40 one requires an external regulator? If that's the case, is it better to add an FJ40 regulator to the system or just replace the alternator with the correct one? Thanks in advance for any advice.

 

[DrRock]

The way that Alternator is hooked up looks no bueno. I don't have my truck nearby but I've attached images of my new alternator that I sourced. This is on my 1985 FJ60, build date 07/1985. You can see that while my alternator isn't a direct fit, it came with an adaptor pig tail going to the plug socket on the alternator. I suspect that is what is under that ball of electrical tape in your photo but only one wire is coming out in your photo where mine has two. Let us know if you need any other information.

 

[Schroedinger]

Thank you. Where is the voltage regulator supposed to be on this thing, inside the alternator or elsewhere in the engine bay? I suspect I'm currently running no voltage regulator whatsoever.

 

[bhsdriller]

stock they're on/in the alternator

 

[Seth S]

The oem alternator had the voltage regulator bolted to the outside. Most new ones have an internal regulator. If you e gotten an alternator that doesn’t have a regulator internal and none external it’s probably running unregulated and that’s why your charging voltage is so high.

 

[3_puppies]

X2 to what @Seth S stated above, make sure it is an internally regulated alt.
pre79 US spec 2F's used externally regulated alt

 

[MDH33]

FJ60 has External voltage regulator alternator like this:

 

[Spike Strip]

You have the wrong alternator and no voltage regulator, thus the high charge voltage.

Non-USA 60s. As well as fj40s have an external regulator.

You want the one with the regulator clocked at 2:00 pm ( you view the clocking from the rear of the alternator)

 

[3_puppies]

FJ60 has External voltage regulator alternator like this:

View attachment 4013262

that is considered an internal regulated alternator, as it is all in 1 package
the externally regulated alternator has a black box located elsewhere to regulate the voltage, on mid 70's 40's it was bolted to the firewall

 

[Spike Strip]

@Schroedinger

This is a USA spec truck, yes?

 

[Schroedinger]

@Schroedinger

This is a USA spec truck, yes?

Yes it is. Looks like I need to track down a new FJ60 regulated alternator.

 

[3_puppies]

Yes it is. Looks like I need to track down a new FJ60 regulated alternator.

where are you located in MT?

 

[Schroedinger]

where are you located in MT?

I split time betweem Bozeman and Atlanta. The truck is in Atlanta right now, I’m going to work on it over the winter and bring it out in the spring.

 

[3_puppies]

I split time betweem Bozeman and Atlanta. The truck is in Atlanta right now, I’m going to work on it over the winter and bring it out in the spring.

I was going to offer an extra to check and make sure, but that won't work. Reman from Toyota would be a good option