Hi Guys, glad to see that such a forum exists!

I'm driving a 1984 Toyota Mini Cruiser (motorhome built on a pickup frame) across the country and am having tons of "fun" making everything keep working.

Ongoing issue, the system is putting out as much as 18 volts while running, and this is causing all sorts of problems (blowing lights, frying inverters, cooking my battery, etc. etc.). I actually already replaced the voltage regulator with one ("tested", used) off the internet, and the problem persists.

its a 22r engine with the old alternator (volt regulator is separate). First, does anyone have experience with this systen, who could provide some advice for troubleshooting this issue?

there are two connections coming from the alternator - one goes to the volt regulator (3 wires), and the other goes directly to the battery isolator (there are two batteries on this rig). I'm wondering if its just hooked up wrong - like shouldn't the wire go from the alt to the reg, and then to the isolator? or is it correct that the regulator gets its own line to the alternator, and then regulates the signal that goes to the battery.

anyways i'm stumped, and also a little worried because i happened to check the 2nd battery after a mountain run yesterday, and it was HOT. which means its way overcharging, which is v. bad news. I've got to get these volts down asap, and i don' t know what else to do short of replacing the alternator. any advice would be greatly appreciated!

also if anyone has a wiring diagram for the old alt/regulator setup,

thanks and take good care,
somewhere in new mexico

 

I'm currently fighting the same issues with my 84, only one battery though. Replaced Alt, VR, checked all the wires for continuity, still get 18 volts. I'm out of ideas at this point. Hopefully someone will have an answer.

 

hm yeah, there was a lot of response over at toyotamotorhomes.org ... search for this thread there to read over some good ideas... however have not solved it yet. In fact, after driving like that around the country (i did some manual regulation by switching on the brights & the fan & radio every time it went too high!) SOMETHING fried in the electrical system. Either the distributor or the HV coil, I'm getting no spark and the car has been dead in the driveway for 2 weeks (no time right now),

anyway let me know if you figure it out, it sounds like we've got the same trouble (and beware driving it like that)

p.s. my 2nd battery exploded rather violently in the back of the cab at one point. v. smokey but the designers conveninetly added a drain hole in the battery box, I'm imagining they had forseen that eventuality

 

I read everything on that motorhome thread, was hoping that it might have been a bad ground strap from head to firewall so I made another since there was a bit of corrosion showing.


Didn't help, and I'd already replaced the battery ground cable for a better one and cleaned the chassis and engine grounding points.
Unsoldered the green wire on the original VR (the black one - it comes apart) and it did cut the excite to the alternator and disabled the charge and brake lights on the dash. Sounds like it is the VR, maybe they're sensitive to chicom aftermarkets or I just got a bad one from Autozone.

 

In my '85 diesel there is also an aux battery in the camper area. It is connected to the isolator in the engine area. The unit I have has four connection posts. "A" is for alternator and it should be connected to the regualtor output, not the input. "1" goes to the engine batteries and "2" goes to the auxiliary battery through a 60 amp fuse. The fourth post goes to a wire coming from the harness that is connected to the "E" or "Exciter" post. This allows the sytem to work and the isntructions for my isolator require it for Toyotas.

The alternator is actually an ac device which produces three phases. These are rectified and fed together for the output to the regulator. The regulator limits the output voltageby limiting the current it the field winding.

It sounds like you are somehow connected to an unregulated output. No connections to the isolator should be made that are not regulated. Be sure to read the instructions for the isolator carefully.