bhperry

If this has been covered before I apologize for being repetitive. This is on a Chrokee sport 2001 4.0L. It was doing fine going down the road when the volt meter dropped down to below 9 but it kept rnnng till I got home and shut it off. It cranked up a couple of times after that with the volt meter on or about 11 then dropped d poo wn to below 9.. Now it want crank but a volt meter shows the battery good. I have cleaned all the post and connections plus checking them. I haven't taken the alternator off yet to check it cause I wanted some input before I started tearing things down. And no I not real knowledgeable just know enough to get by so please be patient with me.

nujeepguy

hook a good meter to the batt terminals. should be 14 v running.
pull headlites, it might dip a volt then go back to 14v.
i read 12v when off for a while/overnight.

kemjeep

almost had same problem with my 00 batt. gauge would go down to 9 while driving had v-meter with me opened hood while still running checked as charging at 13.7 chased this for a while turned out when electric fan was running alt. could not keep up, since still under warranty my mechanic changed it so far so good alt. was probably on its way out, i am posting this as you might get info. as what could be wrong with yours. good luck and post the bottom line ps the funny part about the whole thing was when i got home shut it off and restart gauge would reset until next time, days would go by before happening again because was cooler outside and e-fan was not running as much and as long

bhperry

Ok I just rechecked the battery right now the Jeep want start so I used a power pack to start it. With the engine running I get 5 volts and it sounds like it missing. With the engine off I get 10 volts on the battery but it want crank on that hae to use the power pack again. I'm confused.

fb97xj1

Which connections have you checked? Just the battery, or all of them? Thats the battery, PDC, alternator, power and grounds.

You said the battery tested good, but a reading of 10v is way too low imo, and only 5v with the engine running? Thats not good at all. I always shoot for a minimum of 12.5v with the engine off, and a minimum of 13.5v with the engine running. If the battery has removable caps, pop them off and check the electrolyte levels. A battery with low levels can have issues holding a charge, so check. If they are low and/or the plates are exposed, top them off. Distilled water only, no tap. Fill each cell SLOWLY to about 1" or so from the top, or until the water takes on a concave appearance. Recharge and check it again.

Also, dont get any of whats already in the battery in your eyes, and avoid skin contact.

bhperry

First I want to say thanks for your input in trying to help. I have a sealed battery so I cant check the levels like you suggested. I did go back and recheck check my battery. I put a volt meter on it still connected engine off and got slightly over 11 volts. Next I started the engine with the help of a power pack. With the engin running and the power pack still connected the volt meter in the car read 10 volts. I had my wife disconnect the power pack and it dropped down to below 9. While the engin was still running the hand held volt meter read 6 volts. In both test with hand held volt meters I used two diffrent type and got the same results on both. My guess is my alternator is going out and its the electrical stuff running with the engine that pulls the battery down to about half capacity and the alternator is not putting out. Is that a safe guess, just dont want to tear this thing off if I don't have to but no problem doing so if I do. Again thanks for tge help I can do the work of changing out just not experenced at trouble shooting.

BlueRidgeMark

There is no mystery here.

Your alternator is not charging.

bhperry

Thats what I though thanks I do appreciate it.

bhperry

Put a new alternator on but still did not solve my problem. Now the battery is so low engine want run. I'm at a loss as to what my problem is. So I put the battery on a charger and I guess I'll have to break down and take it somewhere unless someone has another idea. I do appreciate those who have tried to help thanks

BlueRidgeMark

Have you cleaned all your connections yet? Battery, both terminals, the ground at the fender (often bad) the lead from the alternator to the PDC?

Just looking them over isn't good enough. Need to take them apart to really see anything, and since you have them apart, you might as well clean them. You want shiny metal to shiny metal. Your cables need to be flexed and yanked and generally mishandled to see if corrosion has crept up under the jacket and wreaked havoc.

bhperry

I did as you said BlueRidgeMark and discovered one small set of wires in the back of the alternator was not plugged in all the way. Gave it a good push heard it lock yanked on it sevseat times to make sure got in the Jeep cranked her up and watched the volt meter jump up to 14 like it should. So think you ever so much Mark you were a real big help. If you still have your Mom (I don't) give her a big kiss and hug from me when you see her.

BlueRidgeMark

Great news!

Glad to hear you got it. It wouldn't hurt to check the rest of the connections. ;-)


I wish I could pass on that hug for you. I lost my Mom a few years ago. Great lady.

I'll give it to my wife instead, okay?