i just replied in flyer182's thread,but i'll start my thread just in case.'98 cherokee,167k.just put in new cap,rotor,plugs,and wires last week.has been running like a champ.last ran it yesterday with no issues;go out this morning to grab a paper and coffee and she won't start.it cranks but it won't fire.i grab my tool to check spark and i have nothing.

go get a new coil and still no spark.all fuses and relays are good,grounds are all good.i run my code scanner on it just to see if it pulls up anything even though i had no CEL on.it says it can't connect to the computer,so i'm assuming my cpu is gone.anyone else had this issue??

 

Before you lay that computer to rest you need to double check your powers and grounds and FUSES. use a test light and verify that you have battery power and ground at the data link connector. Check to see if the cig lighter socket has power the ecm and cig lighter share the same fuse(at least they did in the 90-s) Check the crank sensor

 

i used a test light on every fuse under hood and in the passenger side kick panel.i will check on the cig lighter tommorow.thanks ******.

 

You also would need to check your crank position sensor. That will cause a no spark situation if it isn't working properly. (I'm pretty sure at least)

 

The pickup coil could also be at fault. Why do people automaticaly replace the coil when there is no spark? Coils do not go bad as often as people think. Stop throwing unneeded parts at these Jeeps and do some diagnostics first.

 

Also cumputers don't go out as often as people think.

 

my coil had a small crack by the tower,so it had to be replaced anyway.the reason i said computer is because one of my durangos acted the exact same way and that's what the problem was.thanks all for the suggestions.i will check them all out tomorrow.

 

You're welcome, just please post back the results and solution.

 

corroded cables. take a wire brush to your terminal and your cable itsself. maybe solve the problem?

 

check the major connections.. my buddy has a grand cherokee w/ a 4.0 that he has to pull over about 10 times a day to pop his hood and re connect a connection because it comes undone and shuts the jeep off.

 

it ended up being the crank sensor.thanks all for the help.

 

You're welcome - thanks for posting the resolution to your issue!