Alternator Issue - 2.7l - Halp!

First of all hello to the members of a great forum. I have been lurking here since I bought my 2006 Prerunner and have loved it tremendously.

Until last week. lol

I had a weak oem battery and kept limping along with it until I left my dome light on a week ago and since it barely started the next morning I figured I could go a little while longer with it. Welp, I was nearly 25 minutes into my commute when the radio goes off and miscellaneous lights start displaying on my dash, ie. brake light, battery light, ect. I figure the battery has bit the dust and get another at lunch. Pretty sure the oem went full discharge mode but a new one should fix my issues. No so. New battery won't charge and Autozone says faulty voltage regulator which cost more to replace than an alternator according to my exhaustive 10 minute internet research but I digress.

Anyway, I get my new pn 11194 alternator from Amazon that Autozone and Amazon says is the replacement and start it up. I hook my voltmeter up and at first it shows low to high spikey voltage but then it settles down and displays a consistent 14.01V. Now I also have Check Engine light coming on as well as the other misc lights and as I try to get to Autozone to do another check it starts dying on me and I barely manage to limp past the cops without my lights on to get it back home.

I am at a loss. My biggest fear is that somehow I fried the computer. I have a surgery scheduled next month and don't have any extra money to deal with this right now.

Any ideas?

Thanks in advance.

 

I doubt you fried a computed the fuses would of blown toyota's are pretty voltage sensitive make sure you have good connections I have seen aftermarket alternators cause goofy things until an oem gets put back on what's your amperage out put

 

The voltage regulator is part of the alternator. It's this doohickey I'm holding. Check your ground wire off the battery. Mine was corroded pretty bad, and I had similar symptoms that were hard to diagnose. New battery=didn't work. New alternator=didn't work. Replaced ground, runs fine.


Mine was broken, but the wires still had continuity.

 

Did you get it figured out? I agree, the voltage regulator is more then likely the culprit.

Honestly, just stick OEM parts on your car from my experience. I used to get Autozone crap, and on several occasions i'd have to take the "new" part right back for a swap. (This was on a Corolla DX i used to own).

Olathe toyota gives pretty good deals......i'd give them a ring for the voltage regulator.

https://parts.olathetoyota.com/

 

Charlie the Voltage regulator is a part of the alternator assembly. He has a new one already. I'm not saying that it is good, but it has been replaced.

 

I have always seen very crappy results from the "rebuilt" Alternators, Starters, etc from any supplier. They all suck. I agree with the others here get a new OEM Alternator and charge the battery overnight with a trickle charger and more than likely you will be golden.

All modern cars and trucks are very sensitive to voltage charge of the battery due to all of the electronic controls.

The alternator you have may actually be good. Try trickle charging the battery overnight before yo run it and see if it helps.

 

So I took both the oem alternator and the new one to Autozone and put them on their bench test and they BOTH passed even after their in-car test with the engine running said "Faulty Voltage Reglulator". I tried to do the in-car test last night with the new alternator but the meter said "Battery Voltage Too Low".

Crap, I really don't know what to do now. I haven't checked the battery cables other than clean them so that is first thing to do tonight but I highly doubt that to be the issue.

 

I'll bet you a box of beer that the frame side of your ground cable is corroded.

 

Check all battery terminal connections and grounds. You may be looking at a corroded, or poor connection. They may LOOK fine, but remove the bolts, clean everything, and then bolt them back in. DO NOT USE ANY TYPE OF THREAD LOCKING COMPOUND! Then check the plug that connects to the back of the alternator. The control wire from the ECU is there, and if there is a bad connection the alternator will not operate. There IS a possibility that the ECU has failed, but it is rare for THIS type of failure.

Check the following fuses:
7.5A ALT-S fuse
10A IG1 No. 2 Fuse
10A IG1 fuse

 

Yeah, I will definitely be checking cables but I am not holding out much hope for that due to the fact this all started when I left my dome light on overnight draining an already weak battery, which barely started the next morning. Then 25 minutes later during my commute the electronics start freaking out, ie. the radio goes on and off when I apply brakes, the airbag and emergency brake lights come on ect.

 

Wasn't the cables so into the shop it goes. Boo!

 

Let us know what it happens to be!

 

Happy Days!

It turned out to be the positive cable from the alternator where it goes into the terminal that attaches to the fuse box. I can't get my mind around how that happened the same time that all the previous things happened but whatever, I am stoked I got out of the shop for less than $100. The tech said they did a voltage drop check from the alt to ground and then to the battery and deduced the cable was bad. That was something I should have thought of but oh well, lesson learned.

 

Dang. I owe you beer.

 

You had a smart tech working on your truck. Voltage drop checks with a load are a very quick and reliable way to test a cable.

 

username, I am calling it a push because I should have checked the amp power cable better. I looked at it under the fuse panel after cleaning the ground cable and decided there wasn't any way that it could be corroded so I left it alone.

Looking back I think I might have placed the battery charger/booster thing on the cable that pulled loose. It is heavy and I laid the hood down on it while charging which must have pulled the cable out from the terminal.

Thanks for all the help folks. If ever in Austin, give me a shout and beer is on me.

Also if anyone is looking for a really good, reliable, honest shop in Austin I have found one. They were referred to me by a brilliant electrical engineer at work who has known the owner since he was 10 years old. 5 stars all over yelp.com.

Loving my taco once again!

 

Hook'em