mrbitz

I have had a frustrating and intermitent electrical problem. Something is not working with the charging system. I have a 95 jeep cherokee 4.0 L in line 6. Twice over the last 5 months (when my wife was driving it) the check engine light would come on and soon after the vehicle would die. (for ovbious reason.) Then the battery would be dead and show all the signs of a bad alternator.

The first time it did this we removed the alternator and batter and had them checked out. They both checked out fine. The alternator we had checked at two different places. I put it all back in unsure of what to do next. I left the battery charger on the battery. When I returned it didn't even want to start. My friend began to move around the battery cables at the battery end and it eventually started. As a result I replace the battery cable ends. This seemed to fix the problem. I must not that there was corosion in the cables.

About 2 months or so later the light was left on one night. I attempted to jump it. It fired up fine, but as soon as I would remove the cables it would die. With the recent history and the corosion in the battery cables I assumed it wasn't getting a good connection to the batter. As a result, I went to the napa and bought a bunch of generic battery cable and replaced ALL of it. That didn't fix it. So I again removed the alternator and batter to have checked. They again checked out fine. So it left me one thing. To my knowledge the charging system is essential four components; a battery, an alternator, the wires and a voltage regulator. Well as you likely know the voltage regulator is a parto of the computer (ecu). So I went to a local junkyard and bought a used on from them. After reinstalling everything if worked.

Well again it has been about two months and it is acting up again. It hasn't died. For almost a week I have driven with the check engine light on. For the first two days it was only in the morning. I would turn it on and the check engine light would come on immediatly and the volt meter would read around 12v. Again assuming then that the alternator isn't charging properly. I would drive it and after about 5 miles the volt meter would jump up to 14v. Then on the 3 day it didn't jump to 14v but it never died. I drove it about 40 miles and started it 3 or 4 times and the whole time the volt meter read 12v. That seems like much farther then the battery alone would power it. This isn't the best idea, but I haven't had time to work on it, but over the last few days I have driven it to work (about 8 miles) and hooked up a battery charger to it when I'm at work. Just today, after acting funky for over a week, I was driving and the volt meter was at 12 (as it has been for 4 days) and it jumped up to 14v. I checked it with my own volt meter, just to see if the voltmeter was messing up and it has been working just fine. Any ideas. All I have heard is a ground. But I have wiggled every wire I can find and not a single one has caused any change.

Thanks for reading this whole thing and for any insight you might have!

huntingman2706217

i worked at autozone for awhile and learned that there machines dont always check everything... you can test something thats intermitant... it may be fine when you test it but not when on the jeep... ive also seen the starter play games... on my dodge it acted like my batteries were dead... tested them and sure enough... so replaces (diesel) both of them... (advance said they were bad) didnt fix my problem... pulled the starter... had it tested... they said it was good... and i was at a loss... same as you... finally got where it wouldnt even jump start... pulled the starter again... tested fine again... replaced it anyways... and boom... truck started fine ever since... the starter is a trickey joker also and it sounds like youve done everything right... but some times swappin parts isnt a bad thing... find a buddy with the same motor... swap the parts and see if the problem swaps also... saves the money... oh and you kept saying the check engine lights coming on... its designed to come on for so many miles then go back off so many and so on... but you never said what code popped... thats where i would start probly...