Is my voltage regulator going nuts?

[HawkGunner]

My FJ40 is experiencing a strange battery charging condition. I noticed it when my Ahmmeter in the dash cluster was acting strangely. It was reading about midway, then a little lower than the middle tick mark, then to the regular position about 1/4 in past the middle tick mark, then it would jump to almost a full meter on occasion.

I verified this condition by checking the voltage of the battery while the engine was running. The voltage jumps between 12.8v and 13.5v, and once up to 14.1v.

I checked all the connections and grounds. They seem to be in working order and installed tightly and properly. My only guess is my voltage regulator. I turned the motor off and checked the battery. It's at 12.7 volts, so it would seem it's being charged, just in an odd fashion.

Anybody have any ideas?

EDIT: I also check to make sure the alternator and belt was tightened properly. They are.

2nd EDIT: Now my motor won't turn over. The battery is good, and the engine fuse is also good. ¯\_(ツ)_/¯

 

[HawkGunner]

Update:

Somewhere in the process of disconnecting and reconnecting all the connections and checking the grounds, the truck started. But I'm still experiencing the same strange battery charging condition.

This feels like it will be a "well, that was stupid" kinda fix... but it's evading me as of now.

 

[bj40green]

If you have a 3 wire VR, the VR checks the voltage coming from the ign key.
So if your ign switch is bad your VR will respond to that.
Tap your ign key/switch or wiggle the key a bit to see if the problem disappears.
Make sure that your VR is properly grounded. Also check the ground wire between VR and the alternator.

Rudi

 

[HawkGunner]

If you have a 3 wire VR, the VR checks the voltage coming from the ign key.
So if your ign switch is bad your VR will respond to that.
Tap your ign key/switch or wiggle the key a bit to see if the problem disappears.
Make sure that your VR is properly grounded. Also check the ground wire between VR and the alternator.

Rudi

VR has 6 wires. It's a component ground, correct? I cleaned the back plate and firewall where it connects, and reinstalled.

I wiggled the key and nothing changed.

Could it be I have a bad battery? Would that cause this condition? It's reading 12.6v now after driving about 7 miles since the first post.

Here are some pictures of the Ahmmeter with nothing on but the engine running, then the fan blower at full, and then with the headlights and fan. Are these normal? They don't seem normal, but this is my first FJ40

 

[HawkGunner]

@bj40green , the ground wire between alternator and VR is the single wire coming from the alternator, not the plug, correct?

 

[ToyotaMatt]

@bj40green , the ground wire between alternator and VR is the single wire coming from the alternator, not the plug, correct?

do u have a fcatory toyota regulator with the Foil decal or lime green stamped part # on it NipponDenso 27700- # # # # #

might be 27700-36010 27700-54020 something to that effect ......

call your local toyota dealer , U will be surprised hot Reasonable Cost they are to simply replace $27-$38 range

 

[HawkGunner]

do u have a fcatory toyota regulator with the Foil decal or lime green stamped part # on it NipponDenso 27700- # # # # #

might be 27700-36010 27700-54020 something to that effect ......

call your local toyota dealer , U will be surprised hot Reasonable Cost they are to simply replace $27-$38 range

Just ordered the last one in the country, apparently. $51.99. It comes in Friday.

But i'd still like to figure out if it actually is my voltage regulator. I put a newly remanned VR from SOR on just a few months ago. I realize new parts can be bad or s***ty out of the box, but I also don't like throwing parts at a vehicle and seeing what sticks. That gets expensive.

 

[White Stripe]

I just bought a solid state voltage regulator. Haven't installed it yet, but its pretty much a direct replacement supposedly. It was like 30 bucks. My current one doesn't charge very well after the vehicle has been run 4 or 5 hours continuously and let the voltage below 12volts.

 

[FJ40Jim]

Could be normal operation of a mechanical VR.

 

[HawkGunner]

I just bought a solid state voltage regulator. Haven't installed it yet, but its pretty much a direct replacement supposedly. It was like 30 bucks. My current one doesn't charge very well after the vehicle has been run 4 or 5 hours continuously.

Where do I get one of those?

 

[FJ40Jim]

Rockauto.com
KVR514 by Kempart.

 

[White Stripe]

Where do I get one of those?

I had to search old ih8mud threads for like 30 minutes to figure it out. Depending on the year their are different versions. Mine is a 77, so I got the solid state that matches a 77vr. Do a google search for ih8mud 40 series solid state voltage regulator. That then led me to some sites I found several different ones. I found mine on ebay though once I got the part number.

 

[White Stripe]

Or just listen to fj40jim haha. He knows more than me.

 

[numby]

Land Cruiser alternators for these years are notoriously underpowered by today's standards and the ammeter readings will fluctuate pretty wildly as different electrical components are switched on and off. The readings in your photos of the ammeter look normal if your alternator is on the weak side...at least if that was my '78 which has the earlier 3 wire VR (single fusible link vs dual IIRC). The fan blower will yank some current for sure especially if you have a rear heater/fan. Headlights will dim at idle, etc. There are several different alternators available in the '78-79 range as I remember. Not a big difference, though. I think 45amp versus 55 amp or something like that. When I replaced mine I had much less noticeable swings in the ammeter readings when running the new alternator compared to the tired older unit - but I can still watch the needle jump with every on/off click of my turn signals.

If the ammeter needle is jumping all around when under a consistent load (and assuming you have an original VR) AND your alternator is good I'd think the VR points are corroded or simply out of adjustment and occasionally sticking and/or not making contact. You can pop the cover and lightly file or sand them smooth and then bend the arm to factory spec. Did wonders for mine when I did that. The newer OEM replacement voltage regulators are solid state which is why there's no longer a core charge. Just plug it in and go. Try to adjust yours first. Then when you get the replacement you can switch them out and throw the old one in the glove box as a spare knowing it will work well enough to get you home.

 

[HawkGunner]

Could be normal operation of a mechanical VR.

I suppose it could be. I have an hour round trip to make tonight, and I'll take the 40. It Just seems like I should have at least 13.5v charging during normal operation on the battery. And I don't have that.

 

[HawkGunner]

Land Cruiser alternators for these years are notoriously underpowered by today's standards and the ammeter readings will fluctuate pretty wildly as different electrical components are switched on and off. The readings in your photos of the ammeter look normal if your alternator is on the weak side...at least if that was my '78 which has the earlier 3 wire VR (single fusible link vs dual IIRC). The fan blower will yank some current for sure especially if you have a rear heater/fan. Headlights will dim at idle, etc. There are several different alternators available in the '78-79 range as I remember. Not a big difference, though. I think 45amp versus 55 amp or something like that. When I replaced mine I had much less noticeable swings in the ammeter readings when running the new alternator compared to the tired older unit - but I can still watch the needle jump with every on/off click of my turn signals.

If the ammeter needle is jumping all around when under a consistent load (and assuming you have an original VR) AND your alternator is good I'd think the VR points are corroded or simply out of adjustment and occasionally sticking and/or not making contact. You can pop the cover and lightly file or sand them smooth and then bend the arm to factory spec. Did wonders for mine when I did that. The newer OEM replacement voltage regulators are solid state which is why there's no longer a core charge. Just plug it in and go. Try to adjust yours first. Then when you get the replacement you can switch them out and throw the old one in the glove box as a spare knowing it will work well enough to get you home.

What is factory spec? Do you have a link to the info?

EDIT: Here's the inside of mine

 

[HawkGunner]

@bj40green , I found your writeup from several years ago on 40 series voltage regulators: Voltage Regulator (ext.) / How it works

It's a very good explanation. Thanks.

I like electrical work, though im not very good at it sometimes. But, if I understand the operation of the regulator properly... with the recent installation of my DUI HEI, and in conjunction with a fairly low powered generator, this very well could just be normal operation for my 40.

I actually had another remanned regulator lying around, I installed it, and it's functioning in the same way. As far as my DVOM is telling me anyways. Being that all my grounds and connections appear to be in good order, does this sound like a fair assumption to you? Your electrical knowledge is superior to mine.

I suppose as long as my truck runs appropriately, and the batter doesn't die on me... It's not really a problem.

Would you advise adjusting my regulator for a slightly higher output by bending the springs? The new one doesn't need cleaning or anything.

 

[numby]

What is factory spec? Do you have a link to the info?

Your points don't look too bad. To adjust you bend the adjusting arms on top until you get the regulated voltage of 13.8-14.8V. (Unplug regulator while adjusting.) There's also a relay actuating voltage adjustment on yours as well which is 4.5-5.8V. Which of your points is which I don't know. This is from the factory 2F Engine Repair Manual publication #98126. There's a whole series of resistance tests outlined in the manual. I wouldn't try and mod the regulator. Your charging system/wiring is likely pretty old and was not designed to be souped up. Rudi knows a heck of a lot more than I do on this stuff.

Could be normal operation of a mechanical VR.

Seeing as how the other regulator gave you the same readings I'd think this is the last word... from one of the gods.

 

[bj40green]

My FJ40 is experiencing a strange battery charging condition. I noticed it when my Ahmmeter in the dash cluster was acting strangely. It was reading about midway, then a little lower than the middle tick mark, then to the regular position about 1/4 in past the middle tick mark, then it would jump to almost a full meter on occasion.

If this happens when the engine is at idle and you don't turn things on and off then there is a problem.
Grounds can be a problem but the VR regulates the output of the alternator according to what he (the VR) senses.
So, the VR senses the voltage on the IGN key/switch. If this voltage goes up and down for no reason, the VR react accordingly.

Also; The connector on the alternator has a wire called N. This wire indicates if the alternator is working or not and sends a signal to the VR (N terminal) and turns on and off V relay which acativates the V regulator (see diagram).

Long story short: if there's a problem (bad contact) with the connector on the alternator it can lead to the same problem.

Rudi

 

[HawkGunner]

If this happens when the engine is at idle and you don't turn things on and off then there is a problem.
Grounds can be a problem but the VR regulates the output of the alternator according to what he (the VR) senses.
So, the VR senses the voltage on the IGN key/switch. If this voltage goes up and down for no reason, the VR react accordingly.

Also; The connector on the alternator has a wire called N. This wire indicates if the alternator is working or not and sends a signal to the VR (N terminal) and turns on and off V relay which acativates the V regulator (see diagram).
View attachment 1712788

Long story short: if there's a problem (bad contact) with the connector on the alternator it can lead to the same problem.

Rudi

Thanks for your reply.

I've had a number of electrical problems today, especially now that I'm going through with a fine toothed comb and fixing all the PO's electrical hack jobs. And, electrical connectors just don't seem to last 40 years. In any case, I had to re-seat the wires In the fuse box, and replace and repair connectors on the starter. I also removed and cleaned all the grounds in the engine bay.

Tomorrow I'll go out and re-pin/solder/otherwise refurbish the alternator plugs as best I can. Hopefully that fixes the issue. If not, I'll keep on keepin' on until it is fixed.

I appreciate everyone's input and assistance with my questions. Thanks!


EDIT: And, since I've got another new VR on the way, Im going to install it under the hood as a backup.