i need help from you guys. my 94 cherokee xj wont start.i already check all the sensor, the ignition coil,ignition cable,spark pug and the condition are good.i can crank it but it wont start. i'm really dissapointed right now.help me please!!!!!!!!!!!!!

 

You say you checked all sensors. Did you check ac voltage on the ckp sensor?

 

Have u checked/cleaned all ground straps? They are VERY important. Do u have a big fat spark? Do all your gauges work properly when u hit the key?

 

Do you have good fuel pressure? Does the enginge crank, but never catch? I don't know about your year model, but check your autoshutdown fuse. The ASD fuse is located in the fuse box in the engine bay. Also check the ASD relay while you're at it.

 

I believe the asd kills all spark and injector pulse. So if you have any spark and fuel on the plugs it may not be the asd. But an easy way to check is to just stick another spare one in there. Its always good to have a spare relay around, they aren't that expensive. Sometimes you can pull it out and it will click, then you know it was probably tripped.

 

The Auto Shut Down fuse & relay are on '91 and up Chrysler systems. The ASD system sends B+ to the ECM, Coil, injectors, fuel pump, etc...

 

When this happened to me (out in the middle of the desert), I got good fuel pressure, but I don't think I had spark. One of the guys I was with was a BMW mechanic and he tried convincing me the computer was shot and needed replacing. (Typical) Ended up being the ASD fuse that was getting tripped because of a short in the front O2 sensor wiring. You can check that, too, btw. Runs from the fuel rail area down to the O2 sensor. My wire insulation was brittle and flaking off; the wires were contacting each other and causing the ASD fuse to trip. A battlefield repair using duct tape worked to get me out of the desert, but in time, it didn't last. I had to replace the O2 wire harness. If you check, you HAVE to check under the wire loom. My destroyed wire insulation was hidden quite nicely under the loom.

 

thank you guys,i'll try to check my ASD fuse first. forgot to tell when i crank the engine there is engine check light appear,do it say that i need to replace my ECU?.my fuel pressure is good.

 

Checking your ASD fuse, relay, grounds, spark, O2 sensors is WAY cheaper than replacing your ECU. If I'm not mistaken, I think the check engine light is primarily an emissions system thing. I'm not so sure it has anything to do with your Jeep not starting.

 

i have checked all the fuses and they are ok..i get from the internet how to check the engine by turning the key 3 times and wait for the signal..i got

can you guys teach me how to check it which cable has shorted?

 

The idle air control is located on the throttle body. It is possible that the IAC itself is shorted. They aren't particularly expensive and if you don't find a problem with the wiring (examine closely), I'd replace the IAC.