BJ74 Voltage Regulator Melt down, need some help (1 Viewer)

[BTC95]

I was driving my BJ74 today and when I stopped and got out I smelled a burning plastic smell and though, someone is having some issues, then I realized the smoke was coming from between my hood and fender. I quickly popped the hood and discovered the wiring to my voltage regulator looking like this.

Anyone have any ideas what my problem is? Pooched Voltage regulator? Short somewhere else?
I ended up unplugging the voltage regulator and drove the truck straight home with no issues and parked it in the garage to investigate. On the drive home everything worked ok and the voltage gauge stayed where it typically does, I am guessing that doing any more driving without a voltage regulator would be a bad thing.

Any help would be appreciated. The BJ74 is my daily driver and I need to get it back on the road asap.
Thanks

 

[danhr]

These relay based V regs are PoS.

See if you notice the points being welded to the contact. I can't make out from the pic you posted. In any case the V reg is the ultimate defaulter in a BJ74. I have witnessed same thing as you have. Just ditch the V reg and get some solid state IC based V reg.

https://forum.ih8mud.com/diesel-tec...v-regulator-there-substitute.html#post5328871

BTW what acc were you running?

 

[amaurer]

First, driving without the regulator is no problem provided none of those wires have shorted together. Your battery will not charge, however, so keep it topped up and you can still use the truck indefinitely.

Which wire is the molten one there? White-Black, it looks like?? The voltage regulator connects to the battery via the charge and engine fuses (7.5, 10A respectively), are they blown?

 

[danhr]

amaurer:

Off the topic ... do you know what that black IC thingy is in the 2nd pic?

Mine got broken off and I do not know its function. Everything seems to be running fine though.

 

[amaurer]

amaurer:

Off the topic ... do you know what that black IC thingy is in the 2nd pic?

Mine got broken off and I do not know its function. Everything seems to be running fine though.

Its a capacitor.

The FSM calls it a "Noise Filter"... same thing.

If you've switched to an IC regulator I highly doubt you need it at all.

 

[BTC95]

It is the wite/black wire that got hot and melted. The only accesory I was running was the radio which is powered by my fused 24-12v converter.
I will check on the fuses.

 

[BTC95]

Well, I have checked with all local supliers and I am unable to find soemone who can supply an IC regulator like you used Danhr.

Would you consider selling your spare and shipping it up here to Canada for me? I would be more than happy to pay a premium on what it cost you.
Thanks

 

[Radd Cruisers]

These relay based V regs are PoS.

See if you notice the points being welded to the contact. I can't make out from the pic you posted. In any case the V reg is the ultimate defaulter in a BJ74. I have witnessed same thing as you have. Just ditch the V reg and get some solid state IC based V reg.

https://forum.ih8mud.com/diesel-tec...v-regulator-there-substitute.html#post5328871

BTW what acc were you running?

Totally disagree. The relay based regulators are very robust and last a very long time, much longer that most IC regulators. I have seen these units last for the lifespan of the vehicle - in excess of 500,000 kms. IC regulators can be very temperamental if not treated with some respect.

There is obviously a problem that needs to get resolved. Have a good look around for a problem (a bad connection, over loaded circuit, chaffed wire etc.) that could be the root cause.

~John

 

[danhr]

amaurer:
Any idea what value? or part no?

BTC95:

Yea I can send it and I am not into 'profit'. PM me. And Radd Cruisers is right about one thing... make sure there isn't some kind of short etc etc.

Radd Cruisers:

I think I have about 5 of these relay type ones that are f'ed up. And I have lost a LOT of money on it. Eventually I developed interest in it and learned how to diagnose car electrical. Still a noob but I am never paying a cent for a relay type regulator. There is a reason they switched to solid state.

I want to debate this topic to clear my understanding. So for one... how is it better than solid state?

Benefits of solid state:

1) Low ripple/noise
2) Lower voltage drop
3) Relay type ones points/contacts can get soldered/welded with load thus fire hazard. The solid state will have protection and pop if failure is to take place thus less chance of fire
4) The relay type ones points/contacts get eaten away with time thus you need to constantly adjust. There are no points/contacts in solid state.
5) Solid state types are cheap ~USD 20. The factory Toyota relay >USD 100
6) With relay type you have to use stock pulley i.e. you have idle (@800rpm) voltage of 24V . If you have acc (audio amp) that voltage drops and you drain battery. With Solid state you can decrease the stock 3.5 inch pulley to 2inch and have 28V at idle thus you can run acc at idle and improve the battery life. (I have done this mod). You cannot do this with relay type since the points/contacts will wear out too early. This mod also gets rid of that effect of lights getting brighter when at higher rpm and dimmer when at lower rpm. Also removes the alt noise from CD player. Finially, you can run IPF 170/100 without revving!

This pulley mod also improves the brakes and clutch.

 

[BTC95]

I have unwrapped the harness from the regulator to the alternator and the white/black wire melted all the way from the alternator to the regulator. And by melted, it heated up so much that it has no plastic/insulation its entire length. Its really hard to tell if there was a short between it and another wire as it partially melted the insulation of several other wires, but none were even remotly close to as fried as that one was. Also, that wire does run directly from the alt to the regulator with no fusable links or fuses between. There were no fuses blown in the panel.
I have started the process of wrapping each individual wire that was partially melted with electrical tape, and I will have to replace the one that did short out. In looking at my voltage regulator, there does not appear to be anything obviously wrong with it. Nothing is burnt or stuck.
Do you think this was just a case of a couple wires rubbing through their insulation and shorting? Or could there be some other cause?

 

[danhr]

BTC95:

If Voltage Regulator is not visibly damaged (points are ok) then there is some other serious problem. The heated wires should be replaced by all means. Duct tape is not a good solution.

I will advise you diagnose and find the cause before replacing anything.

DMM is very handy to detect leaks.

 

[amaurer]

I doubt that it was wires rubbing together.

Examine the regulator carefully, do both relays and every pair of contacts open an close fully?

Also, there are several components mounted on the underside of that regulator, inside a compartment with a press-on cover. Check in there for carnage.

 

[BTC95]

I have thouoghly gone through the regulator, and all points, and contacts are free, the bottom portion also looks ok with nothing visible that gives away there is a problem.

I did not use "Duct" tape on anything. I will be replacing the burnt wire and I wrapped the couple of wires with electrical tape that had some of their plastic insulation partially melted.

 

[nbcnb]

Hello

somebody knows the Toyota References of these males connectors ( before external regulator on HJ61 )

Thanks
Laurent

 

[hj 60]

I had this in my HJ60 but maybe for a long time, don't know why it burned (short?) and replaced burned wire, charges fine, nothing changed when wire was fixed.

More pictures and adjustment/pdf here, to much to copy/paste: 24V glow,alternator,dome,buzzer,battery, electrics - Page 3 - hj60.freeforums.org

 

[nbcnb]

My problem is when starting the engine after stopped some hours or one night , the regulator do not work , I have to knock with a little vibration on the left wing and it works immediately !!! and function all day long without any problem ....
again the day after , at the first start , the phenomemum occure again !!!!!!!!!!! an so on an so on .........
Regulator and alternator are new - my car is HJ61
I would like to shunt this little module just before the regulator just to check if it is not this part which make this trouble ......

if you have more ideas ........

 

[hj 60]

Maybe some factory storage oil burned between the contacts and needs some cleaning?
Replace with other regulator, might be a new faulty one?
Is the alternator giving enough power to start the regulator, my HJ starts charging after glowing is finished (EDIC relay seems to regulate the start charge)
Check charging volt and set it a little higher? :

 

[nbcnb]

my HJ61 is also charging only one minute after engine has started , that is normal on these cars
The alternator is new from Toyota OEM ....