wont start!!!

Hey everyone I've got a 98 xj with some starting Issues..

So leaving work i jumped into my rig tried firing her up started cranking then aboslutley Nothing. So i'm thinking a dead battery. tried jumping her but when i remove the cables it dies. So i get a ride home grab a different battery installed it Go to Crank wants to but Nothing!! But I did notice that when Leaving Jumper cables on for a period of Time When i remove the cables It stays Running. But when I shut Her down and try Firing her up i get absolutley nothing again?? Could this be the altanator Taking a crap?

Any help would be appriciated as i'm not so great in the electrical field.:dunno:

It takes a while, IIRC, for a dead battery to hold enough charge to restart the vehicle after it's shut off. Do you have a plug in trickle charger? That's how I got my crappy AZone battery to hold a charge after my Jeep sat a few weeks with the dome light on (not me, my mechanic :confused1)

Even if your battery was very weak the alternator should keep the jeep running.
I say your alternator has already crapped.

Do you have a multimeter? If you read the battery with the car OFF it should be around 12v. When running, it should be somewhere in the 13.5-14.5v range IIRC.

That will tell you if your alternator is charging the battery. If it isn't, check the ground, the wires, etc. If that all looks OK, swap it out and see if that fixes your issue.

It's certainly possible that your alt has been slowly dying, and the last time you parked the Jeep it just didn't have enough juice to make up for a bad alternator.

Just had first battery checked and it was at 89%. The one I swapped it out with was at 45% Thanks for the advice Guys.
At this point i'm leaning tword faulty cables / ground wire I'll try that first as it looks like there on there way out. Then go from there...

91to99 said:

Even if your battery was very weak the alternator should keep the jeep running.
I say your alternator has already crapped.

Click to expand...

Wrong.

We are way past generators here.

If the battery lacks sufficient voltage the alternator can't be "excited" and won't charge the battery.

1. Start with a fully charged battery, clean cable ends--both ends of both cables. Static voltage between the battery terminals should be about 12.5 volts.

2. Start the engine (if possible) and check the voltage between the battery terminals--should read from 13.5 volts to 15.5 volts, depending on the state of charge and the ambient temperature. If the voltage is too low you are not charging, if the voltage is too high you are overcharging.

3. Do a voltage drop test on both cables to test their condition.

Re: Re: wont start!!!

joe_peters said:

Wrong.

We are way past generators here.

If the battery lacks sufficient voltage the alternator can't be "excited" and won't charge the battery.

Click to expand...

My bad. Thanks for the correction.

joe_peters said:

1. Start with a fully charged battery, clean cable ends--both ends of both cables. Static voltage between the battery terminals should be about 12.5 volts.

2. Start the engine (if possible) and check the voltage between the battery terminals--should read from 13.5 volts to 15.5 volts, depending on the state of charge and the ambient temperature. If the voltage is too low you are not charging, if the voltage is too high you are overcharging.

3. Do a voltage drop test on both cables to test their condition.

Click to expand...

Thanks for the input Joe. I went t the local autoparts store after work to pick up my battery that had a 50% life in it. I left it there for them to charge. When I got there they said it only charged to 65% and wouldn't hold a charge. In the end result I swapped it out for a new one free of charge. Definitely keep you guys posted to what the out come is tomorrow.

How exactly do I perform a voltage drop test?