I just replaced my altinator on my 03 jeep tj because my jeep would not stay running, it would die at low idle. I had it running for 20 mins after i replaced the altinator and shut it off to see if it was charged enough to restart and it wouldnt start so i jumped it again and it still die's at low idle. Have any idea's on what to check next?

 

A few, one thing for sure is the battery needs to be charged. If the battery is low, it will have a hard time bringing it back to life. The regulator on your TJ, is integrated to the ECM. Most of these systems, do not like a flat battery. Your battery will be pulling most of the current, trying to recharge. Your ECM takes a value of amps/volts used, and tells the alternator to produce slightly over that amount. This keeps your battery from being overcharged, and allows for slightly less drag from the alternator. Take your battery out, and charge it, or replace it. For my own uses, I replace my battery with dry cell units (if you offroad and such), for the ease of maintenence.