HO alternator over volting
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JK Newbie
Joined: Jul 2023
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From: Levittown, PA
HO alternator over volting
2015 jku
To make a long story short here I have a js 250 alternator that started over volting right after doing my rad and water pump. (Worked flawless for a while)
Hooked everything back, let it idle to warm up and burp. I got down the road and the bat light came on.
Double checked install, everything fine. It has the big 7 kit. Went through grounds, power cables, 2 pin pigtail, belt and pulleys, etc.
Couldn’t make it right went to put the OEM alt back and it’s perfect. Ended up sending the Js 250 alternator back to company for repair. They say everything looks good. I’m back to square one.
From what I found there’s no battery sensors or IBS. If the OEM alt is fine the PCM should be working correctly right?
What else can I check or try?
Edit: forgot to mention battery voltage is fine at start up then spikes when it heat soaks every time. it usually goes around 15.5. I’ve seen as high at 17+.
To make a long story short here I have a js 250 alternator that started over volting right after doing my rad and water pump. (Worked flawless for a while)
Hooked everything back, let it idle to warm up and burp. I got down the road and the bat light came on.
Double checked install, everything fine. It has the big 7 kit. Went through grounds, power cables, 2 pin pigtail, belt and pulleys, etc.
Couldn’t make it right went to put the OEM alt back and it’s perfect. Ended up sending the Js 250 alternator back to company for repair. They say everything looks good. I’m back to square one.
From what I found there’s no battery sensors or IBS. If the OEM alt is fine the PCM should be working correctly right?
What else can I check or try?
Edit: forgot to mention battery voltage is fine at start up then spikes when it heat soaks every time. it usually goes around 15.5. I’ve seen as high at 17+.
Last edited by Joebo; Yesterday at 02:07 PM.
