OMG...issues. 12.8 charging, why?

Dumb question. How many miles on the serpentine belt?

 

I'm not even sure where they are. My light still hasn't came on. I'm told that could also be a problem.
Will update after my sweat fest....99 in Texas is hot...lol

 

Ok, I've got continuity between battery negative and the alternator case, the body and the chassis (frame).

If i start the Taco and raise it above an idle voltage drops from 12.5 to 11.7 and does not recover.

Im.told the battery light, if blown could cause this because it is the excited wire that initiates the regulator...? Yes?

 

Did the "old timers" way to test an alternator, pulled neg cable off while running. It didn't stall.
I also noticed that the battery light comes on when I turn key on. So it's working.

Maybe that excites wire is broken somewhere or the plug is bad? Is there a way to bypass that wire with voltage to see if it kick starts the alternator? I checked voltage on both sides of that 7.5a fuse and it's 11.8 now.. need put it on a charger soon.

Ideas? Conjecture? Rumors?

 

Alright i got my shit working. So this was an expensive learning moment for me. I had originally ordered a Autozone alt to replace the OEM. I spent $172 on that pos. It never worked when i installed it but, today i took apart my denso and total pro autozone alt. I swapped the Brushes and Voltage regulator(has heatsink fins) over from the AZ alt to the Denso. Installed it and it fired up strong and the battery light went off.

 

I would take the new O'Reilly alt back and bench check it again, if it fails, swap it out for another one, but BENCH TEST the new one before installing it, do multiple pulls on it to make sure it is working, then install and see what happens... I have seen way to many O'Reilly alt fail out of the box...

 

Good job thinking outside the box, Take the AZ pos alt back for a refund...Just tell them you went with a Denso and iit worked where theirs didn't... I stay away from AZ if at all possible, I've had to warranty out wayyyy to many of their junk parts...

 

Pretty simple system, get a test light and check at the alternator connector.

Pin 1 (Yellow) (Warning Light Circuit) Should light a test light and the warning light dimly depending on the wattage of your test light.
Pin 2 (Red) (Ignition Power) (Gauge Fuse (10A)) Should light a test light bright with the key on.
Pin 3 (White) (Voltage Sense) (ALT-S Fuse (7.5A)) Should light a test light bright at all times.


If that checks out then with the engine running meter set to volts DC one lead to the positive post of the alternator the other to the positive battery post and see what the voltage is (should be less than 0.5v).

Also go from the alternator case to the battery negative post and do the same check.


If all of the above check out then you either have spread terminal in the connector or the alternator is junk.

 

White and red light a test light with key on. Yellow does not.

The battery light comes on when key is turned on but goes away and does not delight when running.

Ideas?

 

Interesting that it doesn't light a test light but it sounds like it's working.

Did you check voltage drop on the power and ground like I said above?

 

.02 on pos to pos, 0.0 neg to neg
Multimeter shows battery down to 11.6 now. It's like the regulator isnt kicking on or is bad all together.

 

Should I change the connector for a fresh one?

 

Do you have the ground that goes from your firewall to the engine block? a lot of times this is missing. One should be to your fender from the battery and also the main ground of the battery. I had that firewall one missing and it the lights would dim and brighten with throttle. Replacing that ground fixed that. Not sure if it would fix yours as it sounds like different gremlins but good luck dude.

 

You could but it's unlikely your issue unless it charges intermittently when you wiggle on it.

 

Should i put my

should i put the old brushes and regulator from the old denso into the az one and return it? Thatd be shitty but whats shitty is them selling junk to consumers

 

Shitty would be taking apart a working AZ and swapping out parts, but you got a shitty part from a shitty parts store...


Did they sell you a working alt?? No! You bought an alt from AZ and installed it in good faith that it would work, then when it didn't you wasted even more time trying to re-diagnose a no charge situation, not to mention having to take it back off again, and IF you would have swapped out the POS AZ alt, then it still might not of worked...

Now I would never take apart a new one that worked and swap out parts and then return it, but they sold you a BAD alt that you have double labor in now and wasted your time and gas, and they WILL have to take it apart to rebuilt it anyway, hopefully they will at least bench test it before trying to sell it, they will replace the brushes anyway...

I still think there is a good chance since the OP has already gotten multiple bad alt, that he is chasing his tail with yet another bad alt...

BTW I always bench test every starter myself I buy before installing, they aren't much better a lot of times... lol

 

very true. I only bought the AZ alt bc i needed something overnight bc the taco is a primary vehicle. Will never make that mistake again on any vehicle lmao.

 

https://www.partsgeek.com/catalog/2000/toyota/tacoma/engine_electrical/alternator.html?brand=denso Here you go OP. I shouldve just got this one from the jump.

 

Any luck OP?

 

Right, just can't leave us hanging like that...