thewerd

Hi Guys, I'm a long time lurker, first time poster and mostly giant newb looking for help.

Last couple weeks the XJ has been taking longer cranking to start after being left off 5+ hours, the rest of the time is fine as long as it's not too extended of a period left off. One morning just wouldn't start at all. Later on in the day I was able to finally get it started however it required cranking it for a good 15 minutes, and when it finally started it idled extremely rough, almost violently and acceleration yielded belt screaming. Slight acceleration afterwards would get it to idle a bit more normally without belt screaming.

I could drive it around, albeit it was rougher than normal and felt underpowered. When shut-off, would restart again fine several times with a few minutes waiting intervals, but would not start again several hours later.

I am not hugely knowledgeable, and this XJ is my learning project but I have tried a few things I've noticed from lurking in similar threads.

I can hear the fuel pump going, and when cranking can smell the gas stinking up the joint, so it doesn't seem like it's a fuel issue.

I replaced the plugs and wires yesterday with no change. It's possible it could have restarted by letting it crank again for 15 minutes, but it was so violent last time, It doesn't seem like a good idea.

Is it the timing? CPS?

Any help / guidance would be greatly appreciated. Thanks.

Cherokee 4.0

tighten that belt to start

Abovetimberline

cps can cause this as well as cam position sensor,distributor,your fuel pump maybe running but it is possible it is not pumping like it should.

Stan6406

My 87 did that. Is there anything between that and rain or really high humidity? It was a crack in the coil on mine just took the cover off and had someone crank it I could see the spark arcing. Also make sure you are using the proper swear words and threats ("Jeep you can be a beer can tomorrow") usually works for me.

atomic-xj

Once you crank for a while, the engine will get flooded (as I understand it) and it will run pretty rough once it catches because there is too much gas not enough air. However, it should run good after just a few minutes.

thewerd

It doesn't seem like it is affected by moisture or humidity. It's been pretty hot here lately.

It worked fine right up until a week or so ago.

Turbo X_J

Check the value (ohms) of the coolant temperature sensor. I'll bet when that when the engine is cold you will see a value equating to about -20 F. Let me know if this helps.

'98XJ4life

You have a very similar problem to my '98 XJ where it just won't crank up until I turn it over for awhile. I tried to cooland temperature sensor, new coil, new fuel pump assembly and nothing helped. I even cleaned out the throttle body really well with no luck. So next i'm doing the CPS but i'm hoping that someone who has experienced this same problem will figure it out before me and then clue me in. But Yea, you need to tighten that belt and try not to over flood your jeep when starting it, that'll just make it worse, and you can risk burning up your starter too. There is a way to test CrankPS and CamPS but you'll need a multimeter and some electrical knowledge. Maybe try and find a good shop (NOT A DEALERSHIP!) that can test the sensors for you.

thewerd

Thanks for the help guys. I've got some directions to go in now.

thewerd

Replaced the Cap & Rotor, Ignition Coil, and then finally the CPS.

Started like a champ.

Thanks again.