Jbird76

I have a 2000 Jeep Grand Cherokee 4.7L. Won't start!! Last year I picked it up as only vehicle. I could drive alittle over 10 miles, before it would just die. When I turn on the ignition, the gauges will not go to positions. If I disconnect the battery for a bit, and try the ignition again, the gauges will move to their desired positions and the Jeep will start. So I fixed a bunch of items, and winter came along and my baby seemed fine over the season. Summer is back and the problem has returned. Soooooo....it's surely a too hot to trot issue. Facts: when it does die, I know when it will start again, by the gauges working or not. Even if I don't do anything, she will come back to life after it cools. Or.... After I disconnect the battery and it cools. What has control over the gauges that is not allowing my Jeep to start when it is to hot.
Please help, only running vehicle. And I'm losing me mind!

Jbird76

All lights work, all power does seems to be operating. No other symptoms except the air bag light coming on and off often.

Jbird76

When the gauges are not working and I know it won't start, she turns over just fine.

dave1123

This is in the wrong section....BUT since this is the jeep I know best, I think I can help you. It's pretty clear to me you have intermittent voltage in your system. The PCM (Computer) will kill everything if the voltage goes too high or too low. I'd say you should check all your ground connections and any harness connectors you can find for looseness and cleanliness. Spray them out with electrical parts cleaner, put a small amount of dielectric grease in them and reconnect, making sure they are secure. Take the ground connections apart, scratch them down to clean metal, and resecure them. Pay close attention to the battery cable ends where the wires go inside the molded lead, checking for corrosion. Make sure they have a tight hold on the battery posts. Make sure the smaller of the red wires that come off the battery and goes to the fusebox under the hood is clean and secure. That wire powers everything except the starter motor.

How old is your battery? It's possible there is a cell connector inside that breaks connection after it gets hot. Only a good load test will find that. I had a battery that was less than 2 years old that load tested good for 20 seconds, then faded away. SO...it would start great, then not carry a load for long.

Your symptoms also mimic a failing crankshaft position sensor. It quits working when it gets hot and works when it cools down. The problem seems to be voltage though because of the gauge antics.