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Discussion Starter · #1 · (Edited)
Okay The Alternator is good and the battery is good!

I have one of each in the car and I have swap them out every which way and I can drive the vehicle no problem. However the charging system is only charging up to 12.8 volts sometimes 13.01 volts it fluctuates and goes up and drops sporadically????

I am baffled and confused! Any questions comments would be appreciated or he’ll call me 774-265-0187 Chris

yes I have a volt meter a battery charger and a extra set of alternators and an extra battery all charged up and nothing charging to factory specs.

I did replace the transmission. Over the summer and maybe I broke a wire or something? Any help would be stellar peeps bros dudes and dudettes let’s be politically correct these days and transgendered (it) ((it’s all good in my book))) 😘❤🥰
 

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Discussion Starter · #2 ·
Okay The Alternator is good and the battery is good!

I have one of each in the car and I have swap them out every which way and I can drive the vehicle no problem. However the charging system is only charging up to 12.8 volts sometimes 13.01 volts it fluctuates and goes up and drops sporadically????

I am baffled and confused! Any questions comments would be appreciated or he’ll call me 774-265-0187 Chris

yes I have a volt meter a battery charger and a extra set of alternators and an extra battery all charged up and nothing charging to factory specs.

I did replace the transmission. Over the summer and maybe I broke a wire or something? Any help would be stellar peeps bros dudes and dudettes let’s be politically correct these days and transgendered (it) ((it’s all good in my book))) 😘❤🥰
OMG it’s a 2010 XLE Front wheel drive if that helps at all and Blue in color with 198k on her! Aftermarket 02 sensors 🤓🤪🤪
 

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I think you should win an award for the most entertaining new member introduction ever.

Back to the electrical problem: the basics. With the van idling, what's the voltage across the battery posts. Not the battery terminals, the actual posts. Then, what's the voltage across the terminals. Then, what's the voltage between the positive terminal and a metal engine part: the head or the block.

I'm asking because a not-uncommon problem is an internally corroded negative battery cable harness. You can check by jumping the negative battery terminal and an engine ground with 1/2 of your jumper cables.

Since the powertrain was R&R'd, my first look would be at grounds. Were they hooked back up? Are they tight and clean?
 

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My money would be on on grounding. Check the ground cable(s): properly attached, contact points good, no corrosion. Also make sure terminals are clean (no corrosion, dielectric grease etc).

On older vehicles I've replaced and/or added a new ground to rule it out as an issue.
 

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This could be for any connection like the + battery post to the alternator. A excess voltage drop there will cause problems. Same as the - post to the engine block and the chassis also. And a problem on one side or the other can make it overcharge or undercharge depending on which side.
So is this vehicle running and starting fine and the concern is the low charging voltage?
FWIW mine has always been in the 13.5 neighborhood and I would expect low 14's from other cars i have had. It works fine though and I have ignored it since.
 

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Discussion Starter · #9 ·
I will have to check my grounds. Car starts but doesn’t produce enough voltage to keep battery charged. 12.6-12.8 at the battery when running with lights on I can drive for two hours no problem. When I shut it off I don’t have enough battery to turn over. Unless I charged it up on a battery charger the night before I can get like 2-5 ignition turn o era to run a-ok 12.6 at the battery to the block also. I am going to take apart fuse block and reconnect all grounds from doing the transmission. I never dropped the cradle I was able to remove transmission and get it done at a 45° angle or so! Lol.

I am baffled. Like I said I have had the batteries and alternators checked at the auto store. I am a beast at changing these alternators tho. It’s so easy!
 

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Discussion Starter · #10 ·
Many thanks for everyone’s replies. I located the problem and it was a bad ground like stated above. Many many thanks. The ground on the transmission below the air cleaner box that was the culprits and I took apart cleaned and greased her up and a little lube goes a long way with this girl! Who k ew? Almost 50 years old and still learning life. Again that’s for the help and replies you guys are the best.

I did join over the summer I did a tranny swap and asked for help. I will have to merge my account. Okay Sienna guru’s TY peace ✌
 
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