XJ_FEVER

Ok, the first time it wouldnt start I replaced the cps. It ran fine for a day or 2. Then I was on my way to work one day and it died going down the road about 55mph. It coasted about 30yrds and fired back up on its own. I drove a couple more miles and it died again. I pulled over and waited about 10 mins, then it fired back up. So I made it to work. Then at lunch time it wouldnt start. So I changed the pickup coil. It ran fine for a day. Then wouldnt start again. I have put on a new coil and icm. Im not getting any spark from the coil. I dont have a meter so I just used a test light on the pwr to the icm. There is pwr when I crank it over(at the yellow wire) The ground is good. The green wire showed no pwr when cranking. The ground at the block is also good.

I love jeeps, and have owned many. Never an xj, and Im starting to think maybe I should go back to a tj. I like the xj though because I can bring along some friends.

Thanks for any help!

Heres a couple of my old rigs
http://img.villagephotos.com/p/2009-2/1335345/2073092

Powersmokein

Iam new to jeeps but not to motors so I'll TRY and help trouble shoot. if your not getting power to the coil first I'd take it to advanced (they have a multimeter u can use) or go buy a multimeter and check the actual voltage level coming into the coil when its off,cranking, and running if it will run. I had a bronco that used to blow up optima batteries,turns out it had a ambulance alternator on it and the system wasnt wired for that,battery was getting to much juice going down the road.Once you get a reading on the coil we maybe able to assist better. But it sounds like if u keep frying coils that to much voltage (or possibly not enough?) is being sent to it) have u tryed 1 of your old coils u took off to see if its bad or if it just didnt want to work at the time?

fivendime

Yes, check voltage when key is in run position. If you can get it running check the voltage coming into the battery. If its much more then 14 its no good. Mine puts out about 14.3 volts in stock form. Also if you can get it running that rules out the Crankshaft Position Sensor or CKP for short.

So do you have a signal at the negative side of the coil? Meaning does the test light flash off and on as you crank it over? Let me know if it does or doesn't.

Have you also checked primary and secondary resistance in the coil?

Huntermac

I had to replace my Crank Sensor not to long ago. I was going to work one morning and it just cut off down the driveway. It could be shorting out maybe but just a idea.

XJ_FEVER

Fixed! replaced the computer and she fired right up!!!

XJmanXJ

crankshaft positioning censer it happoned to mine and is a pain in the butt

BlueXJ

The plug on the CPS may be dirty. I doubt the ECU was the problem. It is either bad or it is good. Never seen an intermittent computer.

Huntermac

Glad you fixed it. How much was the computer?

fivendime

False, ECU's can have intermittent issues. I have experienced it a few times. I found a loose solder connection in one before which would run then stop then run then stop, after a quick solder it never happened again....and a few others had issues that if you kicked them they would work so Intermittent can be an issue with ECU's. But yes, them plugs have a tendency to have issues as well corrosion on terminals etc. a good reason to clean and plug back in.

XJ_FEVER

yea, i pluged the new one in and it fired up. then i put mine back in and it fired up again. so i guess i should open it up and check it huh?