I have a 99 XJ with the 4.0 in it. I can get the engine to turn over but it will not start. It is getting gas, I just put a new fuel pump in it and the fuel rail has penalty of gas going to it. I have checked the spark and it is not sparking. I replaced the ignition coil and the Crank position sensor and still no spark. I only have 5 volts going to the coil. I am thinking that my ECU is bad.
Anyone have a good idea for me to look at?
Thanks

 

Have you checked the pickup coil?

 

no i have not, is that in the distributor? if so i pulled off the cable from the ignition coil going to the distributor and put a spark plug on that to see if i was getting spark before the distributor and still no spark.
if it is not in the distributor where is it?

thanks

 

Hey! I'm having the exact same problem. I replaced the CPS, and the coil. I know the fuel pump is still good because the pressure is right where its supposed to be. Took the Jeep to the dealership this morning and basically paid $142 dollars for nothing! They couldn't figure out the problem...The guy told me the my ECU might be bad, but it was replaced not that long ago......Totally stumped! Let me know if you figure something out Thanks

 

My mistake if you have a cps you dont have that, sorry about that, I would assume it would be the ecu but I dont know that much about them.

 

ctro2000, how much voltage do you have going to your coil? i am probley going to go to a junk yard and get a ecu off of another xj and give that a try.
i konw that i can not get a 2000 ecu because they do not have the same ignition that the 99 has. i would like to know if i come across a 98 if that ecu would work in my 99? but idealy i would want to get a 99 ecu.

thanks for everyones help

 

Hobit, I'm pretty sure the 98 ECU would interchange with the 99. Here is my problem, my xj runs and starts fine 98% of the time, however, once every few weeks it just cranks over and won't fire. I let it sit for a while and it cranks up.....its the weirdest thing. Let me know if you find any thing else out about this very annoying problem. (and no I have no checked the voltage to the coil as of yet...you think the dealership would have caught that though..)
Thanks for your help!

 

No, you were right in your first post. There is still a pickup coil located in the distributor. It's also known as a Camshaft Positioning Sensor or stator, it just depends what store you walk into. Here's a picture to describe the location.


My Crankshaft Positioning Sensor crapped out on me and it was a week worth of work making my Jeep run again. I tested the CPS and it turned out bad, so I replaced it on the coldest day of the year in the snow...not fun. After that, still no spark. I changed out the coil with a brand new one after trying 2 junkyard coils, and had very weak spark. Finally, I went to change the pickup coil but cracked the hell out of it and the distributor was already screwed up because I snapped the "ears" off where the bolts go for the distributor cap. I said screw it and went down to the junkyard to get a new distributor. Put it in and starter first crank. If you decide to change your distributor, note the way it comes out because the new one has to go in the same way. The timing isn't adjustable on the XJ, but it's possible to have an improperly indexed distributor. And if that happens, it'll cause another no spark condition. Good luck with your Jeep.