Jchavis71

Hey guys, I joined this forum because I need help troubleshooting a problem with a 2000 grand Cherokee 4.7l v8. Twice last night, it jerked and flashed the abs and brake lights but went away right away. Today, it didn't have power to even unlock the doors when my wife was taking it to work. I checked the battery and I was getting some kind of pulse and my dmm couldn't read it fast enough. I pulled the battery out and it checked at a solid 12.4v. I put the battery back in and it fired right up. Throughout the night, I kept going to make sure it is starting and it does. However, 3 of the last 5 times, it started, then died right away and the only light that was left on was the check gauges light and I could barely see it in the dark. I go check the battery connections and they are solid. Again, I turn it over and it starts, then fades out. By fading out, I mean the engine slowly seems to lose power and dies, but it's smooth, not jerky. Again, the only light was the check gauge light that's barely visible. Also, when this happens, the clock resets like the battery died too.

I'm afraid to drive this let alone my wife because I fear it will die leaving me stranded. Does anyone know what the heck would cause this and if there's a way to check it without a drb3 scanner?

scottmphoto

You might get more responses if you post in the Grand Cherokee section than in this one.

You might try refreshing all of your grounds. Make sure that they're all clean and shiny. I know that this is a problem on our XJ's.

hbracing13

It sound almost like dirty/corroded connection that are getting a weak signal. Since it starting again without a jump I would rule out battery or alt. You can try the key on, key off five times to see if it will throw a code sometimes they do.

Jchavis71

I have an obd2 scanner and it showed nothing.

hbracing13

Check the battery connections and clean or replace it you have too also check to voltage drop on start up and alt to see if charging. A drb won't say anything better then your scan tool since it not throwing a fault.

Jchavis71

It's charging at 14.5v when it stays running. There's no visible corrosion on the posts or terminals. Either way, wouldn't it stay running after it fired even if the battery lost connection? The drb, I believe, reads more advanced codes. I haven't seen an obd2 that can read ABS/brake codes.

hbracing13

Actron, otc ,snap on etc... can all read abs codes with the right software on them.

Not always if a loose connection is somewhere it will fire up when its has a good connection again. Check your power feed to the fuse box make sure it tight. Has anything been done to it before it started acting up? Also can check the ohms of the power cable it will tell you if any resistance in the cable.

Outlaw450

I've heard a bad Ignition off draw (IOD) fuse can cause strange things but I'm definitely not the authority on any thing electrical.

dave1123

I guess I'm going to have to say this one more time. Check your positive(+) battery cable clamp to make sure it's not stretched and is making good contact with the post. It may feel tight, but if there is no gap between the ends of the clamp where the bolt is, it will not be able to tighten on the post. The reason this happens is because the positive battery post is smaller in diameter, the lead stretches and looses contact. I fixed this by removing the bolt, cutting the slot wider with a Dremel, and reinstalling the bolt, then tightening it only until it started to close the gap.

This problem is not new. It's been around since they started putting batteries in cars. (BTW, I never had this problem with GM side-terminal batteries.)

Bustedback

12.4 volts is not a fully charged battery. What does the voltage drop to when cranking the engine? How old is the battery? A bad, or failing battery will cause all sorts of weird crap to happen, such as warning lights to come on and the engine stalling. The battery you have now has just enough power to crank the engine over, but not enough to supply the fuel pump and ignition with power. When you purchase a battery, don't go for the highest CCA you can find, unless you live in a very cold area. To size the battery take the engine size, about 287ci, and multiply that by 2.5. So a battery with 725CCA will do you just fine and last longer than a battery with 1100CCA. Now if you live in snow country, you will need the extra CCA on those cold frozen mornings.

Jchavis71

I just got done replacing the head gaskets. Everything was following the Haynes manual, the sensors were all left alone aside from being unplugged. 2 fuel injector connectors broke on the clip, so i soldered new ones on. When all was said and done, I drove it for an hour without a single hitch. That night, my wife took the car. On the way to work, she said the engine jerked and the abs, brake light came on just for a half second, then it all disappeared. She said it happened on the way home too, just for a half second again. My first post is what happened last night.

Jchavis71

By the way, we bought this car from a car dealership last year with a new battery. I wasn't upset about the head gaskets going, it was 185k mi when we bought it. High mileage, yes, but I've known jeeps to last a long time and it had everything we needed for the right price. The battery was dead when we took it for a test drive so they put in a brand new ac delco.