wyoming9

iTrader: (1)

Where are you reading the voltage?

Were the returned products tested and what were the results??

Is what ever meter your using correct? The dash light is still on??

Is the battery at full charge when you are testing?? Good Battery??

If the battery is in a discharged state of course the alternator will be putting out full output trying to get it charged back to normal voltage .

Another thing if your cables or connections are corroded or loose that can be seen as a load on the charging system calling for more voltage into the system .

With the onset of China Inc in Parts you might just be having a run of bad luck

KettleHouse

Q: Where are you reading the voltage?

I Was reading it from the battery while running. I tested it with my multi-meter and someone from an auto store tested it with theirs

Q: Were the returned products tested and what were the results??

They tried to test the alternator at the auto store that I exchanged, but for some reason they were not able to get a read, so it wasn't truly tested. The voltage regulator that I exchanged was not tested.

Q: Is what ever meter your using correct? The dash light is still on??

Tested with more than one multi-meter. Both dash lights (Charge/Brake) are still on. I can get them to turn off if I unplug one of the wire harnesses in the fuse box, which cause my headlights to not function, but that dash light turn off (but, the brake light will turn on when I pull the brake). Same high voltage though.

Q: Is the battery at full charge when you are testing?? Good Battery??

It's a new battery

cables or connections are corroded or loose ... China Inc in Parts you might just be having a run of bad luck

Possibly. I have gone through a lot of the wiring, connections and grounds, but still haven't found any wires with any damage that I can see. As far as the parts not working properly before they were installed, that could be, but 2 new alts and 2 new regulators makes me think it is most likely something else.

GuitarMike

Some reasons for that would be:
* something about the alternator popped the new regulator right off, making it fail.
* Some 'expected load' that is always on the alternator is not there now, causing its voltage to surge and kill regulator (see above)...admittedly not that likely, but not 100% impossible.
* you sure the alternator/regulator is for the vehicle? Not something from another model that is running too high RPM and outputting too high a voltage for the reg? Again, not all that likely.

I'd try to see what the voltage feeding the regulator is, if you can. Back to the drawing board...post your 'alternator only' voltage...your 'battery only' voltage (with it disconnected completely)...then the battery voltage after you hook up your cables, vehicle off....then battery voltage with engine running at idle. Then battery voltage with headlights turned on.
You may see your batt voltage dropping right when you hook it up, = a short somewhere.

I am suspicious of your ground connection(s) too, actually. Something weird is going on there - you almost have a short situation with the battery installed. So maybe the batt got fried after all (another test at a better shop, maybe). High current demand can fry the reg also...so, a short somewhere pulling a lot of current may be damaging your battery.
You can do the above tests for CURRENT, too, my man! You'd have to set up in series with the battery + cable, and do what I laid out in italics (except for 'alternator only' at this step)....see what makes a JUMP of current draw. Might tell you something....be aware that when you're starting the vehicle, you can easily fry your meter due to the high draw off the battery, so think it thru before you hook up for THAT part of it!!! I'd get it going and put the meter in series after it is running...

Voltage regulators will only fry if the voltage/current exceeds their rating...maybe it is not rated for the vehicle? Just another wild @ss guess; do the above first.

Keep your cool, don't get overly frustrated - you ARE going to figure this out. It IS something simple (could be a burned out relay or something, too, but maybe you can trace 'good' wiring to there), it just eats up time....

KettleHouse

I finally figured it out!

Long story short, I did not get the right alternator.

The alternator at the auto store that I got was for '81-'84, but it was a "B-circuit", and these have a 6 pin connections (which is an identical connector to the other 5 pin one). So when I installed this alternator, which was the wrong one for the voltage regulator, it fried the regulator.

So after 2 new alternators and 2 new voltage regulators, I found a piece of paper that came with the alternator. It said this is "B-circuit regulator for 6 pin connector, do not use on an A-circuit 5 pin connector". I realized that I was using the wrong alternator for my voltage regulator. I went back to the auto store and they let me exchange it for a different A-circuit 5 pin one. After I installed it, it did not work, but then I went and exchange the voltage regulator and everything works now.

Summary: Was using a B-circuit (6 pin) alternator which was frying my voltage regulator, when it should have been an A-circuit (5 pin) alternator.

Thanks for everyones help and ideas.

KettleHouse

double post

mwc0404

Glad to hear you got it figured out bud.

rsty1

I am having a similar problem with my 88 pickup

rosludos

I just purchased my first Toyota ( 84 4x4, 150k ) pretty sweet ride except for the 6 hrs it took to replace alternator as the bolt was unturned since 84 and totally seized. Only to learn of this handy piece of paper you speak of after installing my new one and frying my voltage regulator. Is there a way to use the alternator I have now and switch the 3 wires going to back of alternator or something else to keep me charging I live 200 km from parts store.

GuitarMike

You'd have to have a look at the wiring diagrams for both circuits, and re-route the wires, of course omitting the "B circuit" stuff. And even then, it could be risky because the regulator may be expecting some other draw that will not be there (could run at a higher voltage than you want). I strongly suggest you not do this, ha ha, unless you're McGyver. You don't want melted wires in places you can't find them!! I would exchange the alternator (sorry it's 200km, but that's the crap we have to go thru for the yota's!!).

wyoming9

iTrader: (1)

That is a good thing to be aware of.

With these trucks being this old and maybe having had 10 owners no telling what may have been done to any of them at any given time.

Perhaps the GM alternator upgrade you have no clue and are new to Toyota engines. Trying to replace that with a stock Toyota one would be very interesting to say the least.

rosludos

Yeah thanks it's my first Toyota 4x4 but Ive been a Chevy guy my whole life so you wouldn't slide one of them past me. I'm pretty lucky with my ride I'm the third owner of it and it's pretty minty. My real 4x4 is a 84 suburban with a 10" lift and 39's with a 454 pushing her where she needs to go. The Toyota is only for economy. Ive got new alt and reg here today hopefully and will swap to the chev upgrade when I kill this one. Thanks for the help.

rosludos

Yep that's got er! New alt and were all good. It's funny the a and b circuit clips are similar enough to both clip in to eachother not much point to that.

lowbugets

Thank you this just made my day.

rworegon

Seems a bit of a strange way to revive a thread that's been dead for several years. So, how did this thread make your day?

Xtracab22r

Just rocked my socks