2013 Alternator Overcharging

Hello Folks
Just joined this forum and tried to find a possible solution to my problem but didn't have any luck going through the threads.
I have a 2013 DCSB TRD 6 Speed new to me a couple of months ago. Bone stock.
I Started having problems on the weekend with it starting. First start of the day was a little sluggish, so I left it running while I made a few stops. Eventually had to shut it off (A couple times), and it started, but again it was sluggish. That evening after it had sat for quite a few hours, I tried to start it but all I got was the clicking of the starter. Boosted it and drove it home.
Started looking into it today and the battery is hovering around 12.35v at rest, but won't turn the starter over. After I boosted it I checked voltage again and it was hovering around 17v!!!!! Immediately I shut it off and started doing research.
From what I have found, it points towards the Voltage Regulator (VR) being pooched. Has anybody else had this problem?? Was it the VR?? Is the VR part of the alternator?? and best of all did this overcharge my battery and fry it??
Appreciate any insight you all might have
cheers

 

Is the 17v is just a surface charge from the booster?

What do you measure with the vehicle running?

What does it drop to when trying to crank it?

Have you had the battery or alternator tested? Those can often be done for free.

Don't start trying to fix something until you've done all the diagnosis.

If it does turn out to be the regulator, yes, it's part of the alternator. You'd be better served to have the alternator rebuilt at a local shop that specializes in such things than buying a reman from a big box store.

Let us know what you find.

 

Thanks for your input.

I don't think it is surface voltage because the battery sits at 12.35v when its not running. When it is running the voltage spikes up to 17v. Would that make sense??

When cranking the battery drops to 8v, which to me would suggest a bad battery as well??

Haven't had the Battery or Alt tested yet, thats on tomorrows agenda. Trying like you say, to do all the diagnosis first

 

Battery should not drop below 9.5-ish while cranking

13.7 to 14.7 is a normal running voltage, dependent on electrical load

It's not common for both units (alternator and battery) to fail at once, but it can happen. A battery with a bad cell can also cause an alternator to overcharge (trying to over compensate) Could be what's happening.

I'm going to *guess* you have a bad battery, and with a new one you'll be just fine.

 

Interesting..... I never took that into consideration. It’s a very good possibility that could be the issue. The few weak starts might almost indicate the cell or cells were on its way out, and now it’s toast.
Makes your *guess* a little more plausible.... No??
Anyway I will get it checked tomorrow and let you know. Any chance I’m doing harm running it like this??

 

replace the battery first and recheck the alt output. if the battery is partially shorted the alternator will go ape trying to fill what it sees as an "infinite hole" of voltage

 

Repeated boosting of a battery is hard on an alternator and it may have caused issues with the VR.

I would monitor voltage but its likely pooched, it will start turning off modules and trigger a multitude of lights at 17 volts. This also risks a battery explosion, especially on an already weakened battery.

I would strongly suggest an OEM re manufactured or a Denso Brand alternator if it comes to that.

 

Yes.

For one thing, computer systems don't like random voltages. High or low.

I'd pull the battery and take it in with another vehicle.

As @b-r-o and @Bishop84 suggest, there are a myriad of potential issues you just don't want to roll the dice on.

 

As mentioned previously battery is usually always the first to go and a relatively easy, low cost fix when you are talking process of elimination game. Do that first then if the voltage continues ramping up to 17V while at idle then the internal voltage regulator is done. As previously mentioned as well, go Denso if your alternator is done. Nothing else.

 

Thanks fellas. I let ya know how I make out

 

So did a little more investigating tonight.....
Took a good battery that I had (posts were on the wrong side, but we ‘rednecked’ it to make it work) and swapped them out.
Truck started fine, but was still reading 17v.
Unplugged the alternator, and the battery eventually hovered around 13.5v. Even with a bunch of stuff turned on.
Shut it off and it started again with the battery hovering around the same 13.5v.
Sounds a little more like the voltage regulator went, then fried the battery.
Thoughts??

 

I agree, an overcharging alternator boils a battery. They usually swell and smell terrible.

Make sure to check your belt condition prior to alternator replacement! May as well change it while you're shoveling cash at your truck!

 

Bishop84 good point. It’s all going to be apart by the sounds of it

 

The voltage regulator is an electronic item. If the charging steps down to 13.5 when you unplug the large connector from the alternator that would indicate that by eliminating the voltage regulating electronic circuit, the alternator is now operating as designed but will still require replacement.

 

Makes sense.
Any idea if just changing the voltage regulator and not the whole alternator is an option??

 

You can but based upon its location if you screw up you gotta take it all off again. I'm not even sure if they sell parts individually for a rebuild.

 

No, those days are over. Just replace the alt and move on.

But also check the cable connections really good like in the fuse box. Make sure they're not loose or corroded

 

Too bad. Nobody’s fixed anyyhing anymore. Throw it out and replace it.
Just about to start watching some videos. Is changing the alternator a big task??

 

Where do you think remanufactured alternators come from? Any reman from a reputable brand (like denso) would be fine

 

No, per FSM you need to do a lot of crap but I've been able to pull mine out through the wheel well in the side of the road. Only had to loosen the belt.
Change the belt too so you'll have a spare.