Okay, here's the information:
1980 Toyota HILUX 4WD 20R engine

I recently purchased this beauty for 500 bucks and noticed that the battery was operating the ignition system (removed the battery cables and engine shuts down). Obviously the alternator and/or regulator are bad. I went about hunting for the problem, but couldn't find the issue. I hastily changed out the alternator and regulator in a desperate attempt to fix the issue-NO LUCK.
Here's what I do know at this moment:

alternator works- puts out the proper voltage/amperage

regulator works- passes continuity/resistance tests

wiring is good as far as I know- traced the wiring and there is continuity

Battery is BAD-wont charge over 11.5V, but it still shouldn't matter. If the system was operating properly there should still be 14.5V going past the terminals with the engine running, and the engine should continue to run with the battery cables removed. Battery is strong enough to start the engine and run the car. I've even driven it around town. Voltage is 11.5 both static and while the engine is running. when I put a load on it (radio, lights, etc) it drops down to 11V.

GEN light is functioning but NOT LIT while the engine is running???????

I performed every test in the HAYNES manual and the tests say that the damn charging system should work. If it weren't for the battery terminal test I would say the battery is the issue, but the alternator should run the ignition system with the battery removed once it's started. WHAT THE HELL IS GONG ON HERE????

 

You need a good battery...swap one from something else and see if it clears up.

 

hilux, thanks for the reply. I knew someone would focus on the battery. I did swap out the one from my Camaro. Here's the result:

12.5v static, 12.5v at idle. Engine cuts out when the negative (or positive) terminal is removed. In other words, the battery is supplying electrical power with the engine while running.Period. 14.5 volts should bee seen going across the terminals.

The alternator, regulator, and wiring appear to be working, but the system is not supplying power to the ignition system or charging the battery. The battery is therefore taking up the work. Even with a BAD battery the alternator should take over once the engine is started. You don't even need a battery there as long as the engine is running.

I'm obviously missing something and it's driving me nuts.

 

Well you covered the bases. Checked all grounds....fuses...make sure no missing fuses....easy to look over an empty slot that needs a fuse.

Other than that...get a new reg. If it doesnt cure it....take it back.

Its gotta be some weird thing...cause you seem to be doing everything right.

Saw you changed the reg...maybe its a bad one...happens

 

That is the biggest problem: "hastily".

Where did you measure voltage and decided alt is good? Who much did you measure?

Continuity from where to what?

Removing the battery while engine is running could cause spikes and damage more parts.

Correct. If you're reading 12.5V at idle, it means your alt is not putting uot right voltage.

how can yo say this when you said you're reading 12.5V at Idle?

See Charging System explained on my sig? Charging system is simple. Should apply to most basic vehicles. Compare to schematic of your model-year, and measure voltages at points/pins noted on post.

 

The electrical guru has arrived. He's gonna fix ya up now.

 

LOL!

I hope you guys all had a fine Thanksgiving.

 

Sure did boss. Your electrical stuff has helped countless people. you deserve some props.

 

RAD:

measured alt voltage at the "b" terminal like the manual says. 13.5 volts at idle is what I got and what the manual says is supposed to show up.

measured continuity from the alt to the regulator. Tested the regulator with an ohm meter and it passed.

reading 11.5v across the battery, not 12.5. battery is crap (wont charge past 11.5, but still enough to start and run the engine) 11.5 v is the battery voltage, not the system voltage. the alternator voltage/amperage is not making it to the battery.

11.5v at idle. what I mean is that individually each system (alt/reg/wiring) tests good for some reason.

 

Where in San Diego are you?
Got schematic?
Checked voltage at IG (red wire?)
Battery can still crank around 11V. However, you may have a dead cell?
Even with your Camaro's Battery? How sure are you that the camaro's batt is good?