1981 Bj40 charging problem! (1 Viewer)

[Taraz]

Hellomy name is Carlos i am from Portugal, a need help with my Toyota bj40!

After 6 years seating in my garage, waiting for time and money to rebuild the engine is now back on the road, the problem is that, it doesnt charge the battery, anyway!

New alternator and regulator are on, but still no charge comes to the batery!

From the regulator, i have 3 wires coming to the alternator plug they are:

WG- positive 13v
WL( white and lightblue)- nothing
WBk- earth from the regulator

The other one is going through the regulator, and after directly to the batery i supose, it is a WL wire also!

If i disconect the altermator from the car and test it it works just fine, with earth on one of the pins and 12v on the other it goes to 14.7v easy, ones in the car it doesnt charge the batery!

I have 3 doys locking for the problem, new alternator and regulator, and nothing!

Can any one please help me with this one, i will be so thankfull...

Regards to everyone from the forum!!!

 

[pithicus]

Could it be a blown fuse? I suppose you have checked that.
assuming the WL( white and lightblue)- terminal is the one that makes a field circuit via the charge lamp, you could try a 12v test probe light from this terminal to the battery positive and see if the light goes out and starts charging.

also does the charge light come on when the ignition key is on? If not , wiring or bulb or fuse could be the problem.

 

[Solace in Solitude]

I can’t find a legible 1981 BJ40 wiring diagram. @Coolerman has a couple, on his site, but I can’t read them.

I don’t recall the WL wire going to the voltage regulator and the following picture of the relevant portion of my 1978 FJ40 diagram validates that.

Here’s how my ‘78 is wired:

Edit: of course, your BJ40 wiring may differ.

 

[John in Utah]

Obviously a good place to start is checking your fuses and verify all the grounds you are working with.

Your battery wire - the thicker WL wire coming off the B terminal of the alternator - should be connected directly to the battery.

It sounds like you tested the alternator by putting 12v to the F terminal (WG) and measuring 14.7v at the B terminal, correct? Assuming you have some charge on your battery to get the thing started, you can pull the plug to the regulator and test the IGN terminal (BY wire)- you should be getting battery voltage here. If not you have a wiring or fuse issue unrelated to the alternator and regulator.

If that's fine plug the regulator back in and pull the plug from the alternator and test the F terminal (WG wire), this will show one of three things depending on battery voltage. This thread explains how the regulator works and what voltages you should expect to see at that F terminal: Voltage Regulator (ext.) / How it works

I'm basing this off my wiring diagrams for a 3B so hopefully most of it matches up with what you're looking at

 

[Taraz]

Could it be a blown fuse? I suppose you have checked that.
assuming the WL( white and lightblue)- terminal is the one that makes a field circuit via the charge lamp, you could try a 12v test probe light from this terminal to the battery positive and see if the light goes out and starts charging.

also does the charge light come on when the ignition key is on? If not , wiring or bulb or fuse could be the problem.

Thanks everyone for the replys, for the charging light,my bj doesnt have one, it only have a voltage meter, allways on 50 not more not less!

My regulator works with 3wires, and the WL is supose to be positive as the batery is low on charge....

My fuse box, is showing signal of a short somewere, it gets really warm, i checked all wires and grounds and everything sims to be ok, this is why i got a new alternator and regulator...

Really tyred of this situation, car is on my farm, no electricians near, and i cant drive it to one, its all about 35 km from me!

Will take like 150euros to transport the car to the city!

I will try some of you sugestion! Thanks everyone,..

 

[Taraz]

6 wires sorry, my regulator works with 6 wires 3 going to the alternator plug, one to the alternator B

Regards

 

[pithicus]

Hey good luck with it. Older alternator setups can need a dash bulb/indicator to supply a field to enable charge. This may be your problem.
Cheers.

 

[Taraz]

Hey good luck with it. Older alternator setups can need a dash bulb/indicator to supply a field to enable charge. This may be your problem.
Cheers.

Were is that bulb located on a 1981 bj40???

Regards

 

[pithicus]

I am not sure. In the instrument cluster I assume. Would be battery light?
Would wait for 40's experts to chime in.
cheers

Epic fail. I don't think the 40's have a charge light . [from what I have researched]
Sorry for the misdirection.

 

[Travis 76]

If you need to drive 35 k should be plenty fine without it charging. I once drove my '76 FJ40 about 175 miles at night on just the battery as I was having charging problems in the middle of a trip. Finally found out it was the charge fuse blowing out, figured out after new alt and regulator. The cause for me was the aftermarket temp sender was bumping the back of the amp meter and shorting out the system blowing the fuse.

 

[Taraz]

If you need to drive 35 k should be plenty fine without it charging. I once drove my '76 FJ40 about 175 miles at night on just the battery as I was having charging problems in the middle of a trip. Finally found out it was the charge fuse blowing out, figured out after new alt and regulator. The cause for me was the aftermarket temp sender was bumping the back of the amp meter and shorting out the system blowing the fuse.

I have one update, there was a resistance, small one that shows you when the car is ready to start, that was burned, so i connected two wires together, and that was the problem i gess, now the aternator is charging, but batery doesnt hold charge???

Here are some fotos of the conections!

New battery, i drove 18km first start of the engine, and baammmm side of the road! This is why i dont try to drive, and also have no MOT, or insurance as it is stopped for 6 years now!

 

[Taraz]

 

[Taraz]

H o w can i wire a chrging bulb??

The alternator is from a toyota dyna, so i t may need a charging light to do the job! All rest is checked!!!

 

[pithicus]

any chance of reading the model number from your dyna alternator?

 

[Taraz]

Here, foto attached!

 

[Taraz]

 

[Taraz]

27030-56080
100210-2250

Alt. 021000-9930. 2.4 or 24V not sure!
???. 081000-1030 9322

NIPPONDENSO


My batery is a German branded 95ah, 720A


I tried to conect a in line bulb on the BY cables just before the regulator, it goes on and dims after start, but never goes completely off!


Thanks again everyone!

 

[pithicus]

you have a 24v alternator. your bj is a 24v system correct? I think you have to have 2x12v batteries connected in series
The regulator would have to be designed for 24v too.
We'll get there eventually!
have a look at this thread.
2H Alternator Questions - Identifying a 24v vs 12v Externally Regulated Alternator

 

[Taraz]

We never had 2 baterys in the car, we own it from 84! This alternator is not the one i need then, i will get the old one tomorrow and see whats the diference!

Regards, and thanks again...

 

[Taraz]

Can i use one alternator without vacuum pump? I ha 2 here but from other cars no vacuum pump!

Is that a problem?

Regrads