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Unread 11-03-2008, 10:21 AM   #16
gaucho919
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mrblaine is right, that's a common misconception that I thought was true when I bought my wrangler in 05. I used to drive a 91 s10 with a 4.3 and I could bump start it without a battery at all. not so on my wrangler, I have tried it before when the battery died, a buddy yanked me around with an old volvo, with no results, and the only way it started was with jumper cables

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Unread 11-03-2008, 10:27 AM   #17
Wif
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.. it has to be excited to work(really)
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Don't we all
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Unread 11-03-2008, 10:32 AM   #18
DaOne
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Quote:
Originally Posted by mrblaine View Post
Nope, very common misconception. The alternator, as has been stated, needs voltage from the battery to produce current needed to run the rig.

That's another reason why all the manual trans owners are wrong when they state one of the reasons to own a manual is so you can bumpstart if your battery dies. If the battery is dead, you can drag it around the block with another vehicle and it won't run until there's enough juice in the battery to keep it going.

I knew I heard this before and I wasn't crazy

Glad you got it to stay running.
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Unread 11-03-2008, 10:43 AM   #19
robertdeal
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i got a pic on my profile but i want it under my name when i reply to posts
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Unread 11-03-2008, 10:07 PM   #20
Wrangler11
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that's all it took, a good charge. I actually traded in today of a new 08 grand cherokee I'm actually pretty depressed and miss it.
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Unread 11-04-2008, 01:03 PM   #21
Sccafire
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I know you don't have the Jeep anymore but this it what happened.

Its kinda hard to explain but what happens is the computers loose it memory. After the Jeep is restarted it needs to go thru a relearn process.
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Unread 11-04-2008, 03:24 PM   #22
Wrangler11
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^ interesting
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Unread 11-04-2008, 03:28 PM   #23
Jerry Bransford
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What many don't realize about the type of alternator the TJ uses is that it won't put out any power out whatsoever with a dead battery. The TJ's alternator absolutely requires a 12 volt "exciter voltage" from the battery or it won't/can't put any (!) power out. And if the battery is weak, the alternator won't put out enough power so the engine will run well.

So if the battery was so weak that it needed a jump start, the engine will not run once the jump-start battery is disconnected. Fully charge your battery or replace the battery if a load test indicates it is bad and your engine will run fine again.
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Unread 11-04-2008, 04:39 PM   #24
tj99
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My son's ran his battery down twice now, no doors so no headlight chime.

We've had to let the battery charge a bit from the charging source and then it would start but not idle.

Driving it for a few miles while pumping the gas will let the battery charge enough so it runs correctly.
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Unread 11-04-2008, 05:46 PM   #25
Sccafire
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Quote:
Originally Posted by Jerry Bransford View Post
What many don't realize about the type of alternator the TJ uses is that it won't put out any power out whatsoever with a dead battery. The TJ's alternator absolutely requires a 12 volt "exciter voltage" from the battery or it won't/can't put any (!) power out. And if the battery is weak, the alternator won't put out enough power so the engine will run well.

So if the battery was so weak that it needed a jump start, the engine will not run once the jump-start battery is disconnected. Fully charge your battery or replace the battery if a load test indicates it is bad and your engine will run fine again.
Quote:
Originally Posted by tj99 View Post
My son's ran his battery down twice now, no doors so no headlight chime.

We've had to let the battery charge a bit from the charging source and then it would start but not idle.

Driving it for a few miles while pumping the gas will let the battery charge enough so it runs correctly.

That is all part of th relearn process
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