jeep wont start HELP

islandguy89

islandguy89

New member
ok here is what happened i went out to start the jeep a week ago and it was dead i figured it was from sitting for a month so i jumped the battery and it fired right up came back out the next day and it was dead again.Here is what i have tried so far i have charged the battery and i unpluged the alternator and the starter came back out the next day hooked them back up and it was dead again so i charged the battery again and i unhooked my Aux lights and my stereo system came back out the next day i did not hook them back up and it was dead again.Today i checked the relay and everything is hooked up properly I just replaced the relay 2 years ago and the same with the battery.The only thing that i found weird was that if i charged the battery and left the cables off the battery till the next day when i went out and started it it did not start up right away there was a bit if hesitating and then it started but it was dead the next day i had the battery tested by autozone and there print out said charge and retest and that is after it was jump started and sat and ran for 10mins and put on a charger for a couple of hours and advanced autos print out says voltage 11.80v measured 388 cca Rated 770cca temperature 80'f and battery is good but low on charge.If anyone can help me figure out what is going on or what else to check or Do that would be great thanx
 

I've had batteries die slowly, losing one or two cells at a time that act like this, but if Autozone says it's good, then that doesn't seem likely. Sounds like there is a slow leak somewhere. In an older vehicle I had, if I took the keys out and wasn't careful, the switch would stay on 'accessory' and drain the battery overnight. Even if the radio wasn't on.
 
Unhook the battery cables overnight a couple of nights and see if the battery stays fully charged.
 
check your alternator it may not be charging the battery properly. with the jeep running it should be reading around 13-14 on your gauge, if it is and you have a/c turn it on then read your gauge again if still between 13-14 alt is probably good. or just have parts store check it for you
 

Truck is right, first off charge the battery and go down to the Zone and have them test the whole charging system. Your Alt should be throwing out 13.9 to 14.1. Low alternator outputs will kill a battery faster than a bad ground.
Most internal regulators go without making a whimper but leave the Alternator only putting out 11-13.1 volts, barley getting the battery recharged, and allowing it to build up sulfates on the plates, thus reducing its abilities to throw a large amp draw to the starter.
Another is the Diode, this little piece of electrical wizardry allows the alternator to convert AC into DC. A lot of people use a volt meter to check the alts output but miss the DC/AC output reading. Thus it kills off the battery just as fast.


So do a full charge on the battery and have them do a full charging test, that includes the starter to see if its over drawing amps from the battery.

IF everything checks out you will need to run over to a automotive electrical shop and have them do a Timed amp draw on the battery to see what amp draws you have while sitting with the system on and off.
 

OK i think that i have found why my battery keeps draining i unhooked all of my accesories on the battery and i found that my 12volt constant wire for my cd player was pulling 1volt without being hooked up so i aslo unhooked the ignition wire also and it was still pulling 1volt so i then unhooked the wiring harness for the cd player and the drain stopped so left the jeep set over night and it started right up the next day and has continued to start with it unhooked.Now i have no stereo in the jeep and my battery gauge in the jeep goes down into the red when i let off of the gas does anyone know of any way to fix this or what the problem is??
 

(The only thing that i found weird was that if i charged the battery and left the cables off the battery till the next day when i went out and started it it did not start up right away there was a bit if hesitating and then it started but it was dead the next day i had the battery tested by autozone and there print out said charge and retest and that is after it was jump started and sat and ran for 10mins and put on a charger for a couple of hours and advanced autos print out says voltage 11.80v measured 388 cca Rated 770cca temperature 80'f and battery is good but low on charge.If anyone can help me figure out what is going on or what else to check or Do that would be great thanx)

I find that to be wrong. A battery rated at 770cca should test out at minimum 800cca even with 11.8 volts. 338cca test result is too low. I have doubts that the battery is good but instead has a bad cell.
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if you battery gauge goes into the red when your rpms drop, your alt is telling you that its getting ready to kick the bucket.

an old check that everyone hates (but it tells the truth) is to start your truck and unhook the battery. if it stays running, then your alt is good. if it dies, you need a new alternator. lots of people hate this check because they say it will blow your diodes or soemthing like that but i have never blown anything on any car i have done it on, from bmws to jeeps to hondas and anything in between
 
Charge battery to full capacity.Hook up a voltmeter accross the terminals and have someone start the vehicle while you watch the meter.IF your charged battery is at 12 volts or more and the meter reading drops below 8.6 volts your battery is gone! or will soon be.
Batteries are known to take a 12 volt charge and drop dead after one start.The auto store should be able to see that although I dont have faith in too many of those parts guys for real knowledge.
Then once you have determined the batteries condition you can eliminate the CD draw by hooking the CD player back up on the acc side of your ignition so it has no constant power unless ignition is on.
 

OK i got the battery tested again and turns out that there was a dead cell in the battery so since it was still under warranty they gave me a new 800cca battery so i got that part fixed but i still think that the alternator is about to take a crap so i want to upgrade it to a higher amp alternator does anyone know of any good alternators that would work or what kind of alternator upgrade i should do i have looked on the net for upgrades and i havent found any that will work for my 4.2 engine if anyone knows of any please let me know thanx
 
islandguy89 said:
OK i got the battery tested again and turns out that there was a dead cell in the battery so since it was still under warranty they gave me a new 800cca battery so i got that part fixed but i still think that the alternator is about to take a crap so i want to upgrade it to a higher amp alternator does anyone know of any good alternators that would work or what kind of alternator upgrade i should do i have looked on the net for upgrades and i havent found any that will work for my 4.2 engine if anyone knows of any please let me know thanx
Click to expand...

I think if you use the "search" feature on here, you will find an "upgrade alternator" that will work. Seems I remember reading a few threads on that in the past. Fords, maybe???? You should be able to find something out with a search......JeepZ Rules!!!
 
well i found this alternator on ebay let me know what you guys think.is it going to be enough amps and is there any other mods that i will have to make to put this on b/c it looks like it should bolt right on but will i need any different cables or any thing
 

islandguy89 said:
well i found this alternator on ebay let me know what you guys think.is it going to be enough amps and is there any other mods that i will have to make to put this on b/c it looks like it should bolt right on but will i need any different cables or any thing
Click to expand...

Austin, did you forget the link?
 
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