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16 Cat No Longer Charging Battery after a couple of seemingly unrelated changes.

socalfun64

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#1
I really need help with this guys. If not it’s off to the Dealership for diagnostics and I hate taking it there, not to mention the ridiculous cost.

I just recently had my transmission rebuilt by Jon Sipple and put back in by a local shop. The car ran fine but then the next day intermittently wouldn’t start, just click then nothing. It turned out the shop that did the transmission reinstallation left a nut off a big ground from the trans shroud. So once I put a nut on and tightened it everything seemed fine again.

I then added a Zautomotive Double Bypass in the trunk. I hadn’t even plugged in the Burn Box yet but took a drive only to see the batt meter at 12.4 volts and dropping.

Jon thinks the loose ground wire could have shorted or otherwise jacked up the PCM controlled Voltage regulator.

Also, NO Codes, Chk eng light or anything else. The voltage is the same at the battery as at the front Power tap. I drove it to Autozone to have them test the Alternator but when I got there the battery voltage was to low for them to test it (11.4).
 


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Whatknot

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#2
Modern cars charging system is computer controlled.
Even just to switch from a flooded acid cell type, to another type, they may not charge correctly, and need the program changed. So it is possible the programming is messed up, and it needs a reflash. A battery shop would be a lot more help than the clowns at autozone, I've personally found them to be as sharp as a crayon. I would go to a battery broker, ask them, if not helpful, then sadly try the dealership. Make sure they test the actual battery itself, a battery can short inside itself...ask me how I know.
 


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BULL

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Two things, your battery is at THAT age where it's likely in need of replacement.

I've also had luck taking a batter out of my Hellcat and putting it on a trickle charge for an extended period and reviving it.

.02
 


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socalfun64

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https://
Two things, your battery is at THAT age where it's likely in need of replacement.

I've also had luck taking a batter out of my Hellcat and putting it on a trickle charge for an extended period and reviving it.

.02
Thanks, but thats was the first thing I tried. I was actually already a couple years into an AGM battery. I still tried the new battery thing just hoping that was it, lol. Nope. I did the ‘hard reset’ deal as well, holding the cables together off and on to no avail.
 


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https://

Thanks, but thats was the first thing I tried. I was actually already a couple years into an AGM battery. I still tried the new battery thing just hoping that was it, lol. Nope. I did the ‘hard reset’ deal as well, holding the cables together off and on to no avail.

It's literally only been one, but I have heard of a dead alternator on a Hellcat...
 


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socalfun64

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Thread Starter #6
I found this which helps e plain some things but not enough for me, other than I hope I don’t need a new PCM.

1627618655903.png

1627618613108.png
 


2fast4u

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This might sound dumb, but, maybe start car and get a flashlight and look at front alternator pulley to make sure shaft is coupled and turning, not just the pulley...kind of a long shot....
 


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I'd recommend the trickle charger route before buying a new battery. Modern sport cars don't like to sit for weeks/months without use due to all the computer systems/live updates.

Wouldn't hurt to install a new battery anyway considering it's 5 years old. Recommended to change out every 3-5 for most vehicles.
 


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I'd recommend the trickle charger route before buying a new battery. Modern sport cars don't like to sit for weeks/months without use due to all the computer systems/live updates.

Wouldn't hurt to install a new battery anyway considering it's 5 years old. Recommended to change out every 3-5 for most vehicles.
Couple posts up he said he did try new battery
 


MurderCat

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Couple posts up he said he did try new battery
Oops. Hmm...interested to see what the issue is.. Maybe the Alternator or loose wire as others said.

Also could be parasitic drain from a dash cam/aftermarket security system - Happened when I had LoJack on a car. Went through 2 battery's until the battery shop found the black box unit previously installed by last owner.

Good luck with the repair OP.
 


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#11
If they jackw wiring, usually inadvertently, while doing something unrelated to car can cause a rub and ground / draw that is ridiculously hard to trace.

Or, incorrect ground could have fried a piece of hardware or messed w the programming. See my comments on the low voltage shenanigans of the SC GTO.

Good luck man.
 


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socalfun64

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Thread Starter #12
If they jackw wiring, usually inadvertently, while doing something unrelated to car can cause a rub and ground / draw that is ridiculously hard to trace.

Or, incorrect ground could have fried a piece of hardware or messed w the programming. See my comments on the low voltage shenanigans of the SC GTO.

Good luck man.
I’m kind of leaning towards this as I already spent a few days on my back in this heat looking for an intermittent no start issue. That ended up being an important ground left loose. That may have jacked up the pcm. Everything else seems fine tho and no codes, etc.
I did a scan with hptuners and it showed it being commanded to 14 volts but seeing 12.


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#13
not started should be 12ish, running should be 13.8-14.4
 


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socalfun64

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Thread Starter #14
Yep. I remember when it was charging that it was always above 14. For the comment about the trickle charger, thanks, I’ve always kept all my cars on trickle chargers because of the cold winters up here i the mountains.
 


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socalfun64

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So, I guess my only option is to try changing the alternator even though everyone I’ve talked to about it says they rarely go bad and it would have to have been a crazy timing coincidence to go out right when it did. After that is a trip to the dealership.They better be able to figure this pos out! I’m really losing my patience with this car.

I’m so surprised that nobody has had this happen or heard about it on the Forum, at least those who’ve viewed the thread. I swear, I have the worst luck with this car. It’s freaking unbelievable.
 


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So, I guess my only option is to try changing the alternator even though everyone I’ve talked to about it says they rarely go bad and it would have to have been a crazy timing coincidence to go out right when it did. I’m so surprised that nobody has had this happen or heard about it on the Forum, at least those who’ve viewed the thread. I swear, I have the worst luck with this car. It’s freaking unbelievable.

Obviously get it tested prior to ripping it out.
 


Whatknot

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Obviously get it tested prior to ripping it out.

Definitely!
 


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A battery shop would be a lot more help than the clowns at autozone, I've personally found them to be as sharp as a crayon.
This is the best analogy of Autozone I've heard, I chuckled when I read that line [like]
 


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socalfun64

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Thread Starter #19
So it turned out to be a bad Alternator after all.

I’m not sure if it was a coincidence that it was at the exact same time as I installed the Zautomotiv double bypass incorrectly. Due to confusing (for me ) color coding in my 16 Cat and the Instructions it was initially installed incorrectly.


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#20
It is a 2 year battery,,, it is for only 2 years. Replacement is $178. I have had soooo many problems with the battery. If it goes dead, like living in Deadwood, can't open the trunk where it is stored. Have to jump it from the under the hood and get enough juice to open the trunk. At a point like that. Bad boy battery. I have not been able to turn it off and need to drive 16 miles to the dealershitsky. They turn it off and Walaaa. It want start. Welcome to my world 3 times now. Being a 6 speed I have to drive that far with out staling the engine. Or at 93 degrees looking for some one with a triple sized buzzzz boxter. Batterys. Oh crap.
 




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