Weird engine problems...

I drive a 94 Jeep Cherokee, automatic with the 4.0L. Yesterday my battery level dropped down into the red after I started it. The jeep would still start but barely. Drove it to my friends just fine. Went to drive it again and this time all of my dash lights were really dim along with my head lights, still ran just fine though. On a third attempt to start it and drive it home it barely turned over again and my head unit shut off completely and all the lights on my dash were barely visible. It started driving fine but after a couple minutes it started to sputter and barely had enough power to get up some hills to make it home. It would sputter and lose power and then catch and have some power for a second and then it would go back to sputtering and no power. Once I got it back into the parking lot it completely died on me and won't start anymore.

Any ideas on what could be causing this?
Sorry for the long post, just started doing a lot of weird things.

Well, you don't have enough POWER to make things work.

Bad battery, bad cables, bad grounds, bad alternator are all possible suspects.

You have drained the battery to the point it can no longer provide 9+ volts to the engine management system. Electronics get a little freaky in low voltages situations.

Pull the battery and fully charge it, overnight (Ok) or 24 hours (Best), then take it and have it load tested. If it passes reinstall it and then hook a voltmeter between the battery terminals, you should have about 12.5 volts static. Start the engine, you should get 13.6~14.5 volts, if you aren't then the problem is in the charging circuit--alternator, regulator (internal), possible blown fusible link.

Good luck.

Oh, BTW, when your XJ would barely start the first time--that was the time to figure out what the problem was.

Thanks for the input. I am going to take out the battery and have it charged and tested and then check it like you said. And if not then I will have the alternator tested and go from there.

Thanks again,
Matt

Your first step to charge the battery is good. While it's charging, though, disconnect all connections in the alternator to battery circuit. Clean them with scotchbrite or sandpaper, then with brake cleaner, spray start, or electical contact cleaner. Then put it back together. This circuit includes the battery to engine ground as you need to complete both the positive and negative sides for charging to occur.

Your newly charged battery should them fire it up good. Then with a voltmeter, check the voltage directly on the battery. If it is not at least 13.5 volts, your alternator is not charging the battery (like Joe says).

First step should always be to clean the connections.

Well I had the battery and alternator tested and they both passed. So I cleaned all the grounds and replaced the battery cables and it looks like that did the trick. Thanks for the help guys!