Well Jeep just died on me the other day. All it does now is crank over and won't start. I put about 6-7 gallons of gas in it just incase i was just stupid and ran out of gas. Now my gas gauge won't move and still just cranks over.
I can here the fuel pump engage when the key is in the ON position. I tried doing the diagnostic test by turning the key On-Off-On-Off-On and nothing displayed on my Odometer like it has in the past. It didn't even show it ran any test.
I'm going to be switching the fuel filter tomorrow. Just wondering what else should I look into? Am I doing the Diagnostic correctly?
I'm also gonna check the spark after I switch the filter.
There should be a schrader valve (like a tire has) on the fuel rail somewhere. Take the cap off of it, go in and cycle the key on 4 or 5 times until the pump quits. Then with a screwdriver, push the tit in the valve and see if it shoots, dribbles, or blows gas out of the line. It should have quite a bit of pressure on it if the pump is working correctly.
Sounds like a dead short to ground when key is turned on. Realize that doesn't really help-'cept to tell you why you won't have spark or be able to run. Can't complete electrical circuit with a fuse blowing every time so no spark?
I had this happen to me about three weeks back! Hadn't found anyone else with the same problem! At first I thought it was a short in the wiring somewhere, we checked everywhere. Lots of wire looming came off. Sadly, still didn't find it. Thought we might have found a short within a connector. We sauldered it. No problem, drove down the road three miles and the fuse blew, and now it blows them with out the Jeep even starting up all the way. (previously it would run for about a minute.) Tested the coil everything seemed alright. I'm ordering a new PCM today, as I was told a short in the PCM could blow the fuse, and that's the only lead I have now! It seems to me, that we have the same problem!
Dead short to ground means there may be wire that carries a positive signal to the relay that is now touching the frame or body which is your ground. The fuse is there to protect the wiring and circuit from overload and possible fire. If it is a short, they are tough to find.
We tried to trace any shorts or grounds, and came up with nothing. My father was working on it for a while with me, he spent everyday for about a week and half tracing wires. We found nothing. We put in another ASD relay, checked the up and downstream O2 sensors, and we still had no luck. We checked the coil, everything was as it should be. The only thing that we have left to check is the PCM. I'm communicating with a mechanic, and he says that it's possible for the PCM to have a short and ground inside the PCM, and then making the fuse blow. (Didn't bring the Jeep into a shop though! Think It can be fixed with out that!) Unfortunately, the PCM is sealed in silicone, and I can't mess with it, so my only option is to replace it! Hopefully, I will get it, and put it in early next week, and I will be happy to let you know of my results!!
We were persuaded by some Cherokee people who had problems similar to mine, were it seamed as the short was always jumping and moving, and never seemed to be in one place. They said the way they fixed their problems, was by replacing the PCM!
o2 sensor had melted to the header and was grounding out. Wrapped the wires in some electrical tape and then a thermal housing. Also pulled it back away from the header. Now she's running like a charm.
Easy fix to bad it took me a month because I work to much to get a chance to look at it. Hope this helps anyone else with similar problems