rptuel

Have a 2003 jeep grand cherokee 2wd 4.0 automatic. It is blowing a 15 amp fuse under the hood it is for the fuel injectors. It will run for awhile about 45 min then it blows the fuse and dies. Then when I replace it it blows again as soon as I turn the engine over. After it cools off it will start and run for another 45 min to an hour. I have looked at all the wires from the injectors back to the fuse box and the computer all look good nothing obvious shorted out. Shook and wiggled all the connections while it is running and can't make it die. I am thinking something is getting hot and shorting out but not sure what to look at first. Any ideas would be greatly appreciated.

dave1123

After looking at the 17 pages of fuel injector wiring diagrams I have, the only 15 amp fuse I found in that circuit was from the ASD relay to the PCM. Try replacing the ASD relay. That fuse also supplies the injector harness. The ASD relay may be getting hot and dropping out. I'm seeing it as fuse 26, am I right?

rptuel

Yes it is 26 I believe. I will try the relay.

dave1123

I got thinking and the only other thing it could be is an injector that shorts out when it gets hot.

Tankpb

I know it's an old thread but I've run into the same issue along with p1389 code but on a 4.7. Did you ever figure out what caused the issue?

Chrismorton10

that's going to be a bad crank sensor. I had mine go out while I was driving it and it completely kills the motor. What happens is when the sensor fails, the computer things the engine is no longer running and cuts the fuel, and because the crank sensor is basically the sole provider for ignition timing, you will get no spark. Replace the crank sensor. Be careful when you do it because they tend to be A PAIN to get out so just exercise as much caution as possible