So, I have a 1990 Jeep Cherokee I recently replace the alternator, due to the baring sezing up and ripping up the serpentine belt. However whenever I'm driving it now, it'll die when I go to stop and I have no power in the jeep. As soon as I put my jumper box on the battery it'll start right up. I tested my battery, and they said it was bad, so I replaced it. I'm still having the same problem. I have no clue what might be causing my problem. Help! Please!

 

did you put a full charge on the battery? I had this happen when my battery got drained. Just wouldn't run without keeping the throttle open pretty wide. But, my problem was fixed with a fresh battery. I did put it on a battery tender overnight before it went in. May also want to check the other pulleys with the serpentine belt off to make sure they are rotating freely. May also want to check the serpentine belt to make sure it's not too tight and causing drag. What's the voltage reading while idling?
Just to clarify, are you saying you need to put the jumper box on to get it started, even after replacing the battery? If that's the case, then I would definitely make sure you have a full charge on the battery.

 

Same solution still? It stalls, you put jumper pack on and it fires right up?

 

This post is very confusing but I think your problem is relatively easy to figure out.

It seems like the alternator isn't charging and you're running off of battery power. Jeep sucks the battery down and dies.

Test your alternator output when the jeep is running and no jumper pack hooked up. Place your leads on the battery terminals. What numbers do you get? Can you see them decreasing while the jeep is running? Please post.

Test your battery output when the jeep dies. What numbers do you get? Any fluctuation? Please post.

 

The battery seemed to do the trick. I took it back to the place and they tested it and it was a bad battery. ever since I put a good battery in it's been running fine

 

Thats good man, easy solutions are nice. Never hurts to refresh grounds and check cables for corrosion too!