Alright I have a 1990 Jeep Cherokee 4WD FI 4.0 6L Last night I cranked up my jeep and drove to my gf's house. It rained pretty hard, severe thunderstorm, and when I went to leave my jeep would not crank. I replaced my distributor cap and rotor, I have half a tank of gas, my spark plugs and wires are less than 4 months old, there is fuel in the fuel rails and its keeping pressure, the ignition coil and module are tested and work fine. All my connections seem to be fine. I pulled a spark plug out and attached it to the spark plug cable going from my ignition coil and grounded it and tried to crank and I'm not getting a spark. Any reason why?? Please Help this is my DD and I start my new job Monday at 11 am...

 

I`d have to lean towards something gotten wet or a blown fuse/relay related to the heavy rain. There`s a number of them which control ignition. Once you eliminate fuse/relays I`d trace the voltage backwards from a plug and see at what point exactly it stops along it`s path..Failing all that you have to start thinking farther away. Crank sensor etc. Keep us informed of your testing.

 

I've checked all the fuses and relays and sandpapered all of the connections to ensure there is nothing obscurring the connections. It seems like all of a sudden I dont have power to my ignition coil. It will crank forever but will not fire up.

 

Check your cps.

 

I havent checked my CPS yet thats next on my list but after adjusting my number one piston to TDC and pulled my distributor cap off I saw that the rotor was not pointing at the number one spark plug wire. It was pointing 180 degrees away at the number 6 spark plug wire. Could it be that the timing got off? The timing is unadjustable in my jeep though.

 

Nevermind about the timing issue. Being that it was exactly 180 degrees it wasnt on the compression stage so thats all good. Im on the way over there to check the cps and go from there.

 

Ok when out and bought a CPS and unplugged the original CPS and checked it with a meter and it was fine. Plugged it back in and it started up just like that. I guess it wiggled loose. Im still gonna keep the new plug just in case the old one does go bad.