(Solution)
CAM sensor was out of adjustment, hooked up the snap On and set to sync. Cracked the 13mm bolt loose on the cam sensor bracket and adjusted to zero (or as close as I could get.) Mine was initially at +20.

(problem)
I was getting:
p1391 (intermittent loss of cmp and ckp
P0351-0352-0353 (coil packs)
codes immediately after welding a on new exhaust from the manifold back.

I changed the crank sensor twice, the cam sensor once, coil rail, champion copper plugs, tps, cleaned the iac, cleaned grounds and replaced engine ground strap.

(Symptoms)
stalling (this went away when I changed the ckp)
Hard start (most times, hot or cold)
stumbling and missfiring (about every 3 starts)
BUT... Sometimes she would start up and run like a top.

I have been searching forums and Facebook for months trying to solve this issue to no avail. Hopefully this post helps those that have the same problem.

 

I own an '00 and have been fortunate enough so far to not have misfire or heat soak issues.
But I pay attention to these threads when they do come up.
A long time ago I came across this:

https://www.jeepforum.com/forum/f11/...think-2975897/

Which led to this:

http://jeep.blackonyx.net/pdfs/jcss.pdf

To be frank most, if not all, of it went over my head.
Is that PDF similar to how you solved your problem?

 

I didn't come across that PDF in my searches but that would have been nice if I had haha.

It's weird, sometimes it would bark out of the intake in long cranks but because it ran so well when it would start it was hard to settle on timing being the issue. I had 2 different mechanics helping me diagnose this and last night at 10pm we decided to check this. I'm not even sure why we thought of it.

 

Whenever people post this problem I post those links.
Not even really sure if it helps but...... LOL.

 

Hi All,
New here, first post, please forgive any miss steps in asking questions here. My Teenage son has 2000 XJ 4.0. We just installed a rebuilt engine and want to make sure things are running perfectly. According to the service manual, in order to adjust the cam position sensor (after the toothpick manual setting) you need a scan tool to do so to sync it back to near 0 degrees. I called the local Jeep dealer and they said this can only be done with a DRB scan tool and theirs is long gone. They also said they cannot use their snap on scanner to do the adjustment. Is the dealer wrong and anyone with a snap on scanner can do it, or does it really have to be a DRB scanner?

 

That youtube link will show you the same method I used using a scanner.

 

Thanks Justin. Late yesterday I stopped by a local shop I've used for years and talked to the owner. He knew exactly what I was talking about and had no problem helping out on this. I suspect the dealer just didn't want to deal with working on a 20 year old XJ that's been worked on by a driveway "mechanic".

 

Did your mechanic hook up to it? What was the reading?
I'm glad to hear that you had someone to help you.

 

It's not my daily, it my teenage sons, so i just stopped without the truck. Will get it there in the next few days once we get the new exhaust completely hooked up. Running open cats around the neighborhood is bound to **** off the neighbors. Will report back once its done.

 

Feedback after going to a competent mechanic. After I used the toothpick method of manually setting the Cam Positon/Oil Pump Drive, the mechanic found that the timing was 10 degrees out from zero. He adjusted to near zero and reviewed all other settings/sensors and gave my sons XJ a clean bill of health!

Thanks for the help guys!

 

Do you have a part number for this snap on scanner...i assume its more than an obd2 reader..thanks

 

I used an Apollo D9, they are pretty expensive.

Check this link for more info, I honestly don't know anything about scan tools.
https://www.jeepforum.com/forum/f9/s...ensor-1811226/