TJ805

Well I'm hot on the track of the P1391 code. Cam sensor traced out good as far as I can tell, but I found some macgyvering to a wire feeding to what I believe to be the Crank sensor. This plug lead travels down the trans filler tube and crosses over the bell housing to the driver side near the CKPS. There was an evident short inside the plug that's in the engine compartment passenger side and the orange/black wire seems to have been bypassed where it enters/exits the cabin. I'm not sure if you know about the wiring, but check out these pics. I guess the biggest thing is to determine if the wire was repaired as a result of the plug short, or if the plug shorted because of the wire. Though the plastic burned, the connectors are still good...

4x4jeepmanthing

cant say for 2000+ xj, but im pretty sure black heat shrink isnt factory.

check this source out:
https://xjjeeps.com/

2001 manual

8W-80-59

it looks like throttle position signal wire perhaps?

TJ805

Look closely and you can see that the orange/black wires were bypassed, hence the black shrink wrap. The shrink wrapped section should reach to the far left cut wire, but the shrink wrapped wire is actually connected to the cut section in the vertical trunk that should connect to the small nub at the top. I just need to figure out why. The orange/black wire has been traced all the way to the crank position sensor. Signal is lost after the 14 pin connector that travels down and across the bell housing to the ckps. The pigtail that has the 14 pin on one end and splits off to the ckps plug, is definitely where signal is broken. The orange/black pin is where the burn is on the 14 pin...
Thank you for the info. I will definitely look into it...

97grand4.0

I think you're hot on the trail. OK couple pointers, first, the corrosion in the plug undoubtedly is making for a bad to no connection. This is called an OPEN, or ARCING, and it is not a SHORT.
You have an open circuit there, which may be an INTERMITTENT connection or intermittent open depending on whether your glass is half empty or full.. or two or three.Jumpering the wires around the connectors is an option, sounds like maybe it was done before. On my xj I jumpered around a couple of these plugs for the tail lights, ended up cutting off the plug altogether and going one to one with new wires and solder. BE SURE you jump out the wires properly, if they are not color coded, or you will be skay rooed.Good post, makes me want to check mine and spray some contact cleaner.

TJ805

I have two cut wires (orange/black) that remain open. They were cut, crossed, and two ends left open. Why the bypass?

I traced/toned the open ends and know where they terminate. The nubby cut wire on the vertical trunk goes to/comes from the 14 pin, but I lose tone at the next position going down toward the ckps, a pigtail that splits from the 14 pin and picks up the ckps plug.

In other words AFTER the burned/not burned plug, I lose tone. The "burn", by the way, coincides with the orange/black pin position. Combined with the bypass/splice, I deduced a short.

I feel like I should reconnect the proper wires and go from there. I'm glad to have found what I hope to be the problem, but I cannot find that "pigtail" that has a 14 pin male and splits off to several smaller females, including the ckps.

The 14 pin has two open positions btw, so it's actually 12 wire plug. Six in and six out?

NO oxidation or corrosion exists in any other plugs and the Jeep has zero rust, but I sprayed some Dioxit on the contacts...

97grand4.0

That is too much for me to follow. It ran before with no code right? You didn't cut any of those wires right? So I recommend 'ringing out' with an ohm meter to find your electrical open and repair it. You don't have a short. You have a bad connection, which is an open. Unless the funk in the connector is bleeding a bit. it may be in the previous 'repair' splices, or the connector corrosion and corruption. I think .
Good luck

97grand4.0

Something else puzzling me, is this stroker rebuilt 30 over with new pistons, if so, were the rods and mains changed, if so, did I understand that the pressure drops to 20 when hot? curious

TJ805

Well I've been into my wiring harness and found some things that should have been the problem, yet the P1391 code remains. I did have a moment when my reader read it as a "Pending" code, but I couldn't get a clear definition of "Pending". Twice I got "0 Codes" and no check engine light, but this morning it was back on. I feel like I'm barking up the right tree, but just need a little something more. Any help is appreciated...

What I've done so far:
Cleaned and inspected all the related plugs.
New MOPAR Crank Position Sensor.
Repaired three bare wires that were right next to one another on a plug. They were stripped clean about 1" and the copper was bright red and shiny. No burns or corrosion whatsoever. It seemed intentional somehow...
Repaired several wires with insulation that was failing. I used RTV, cloth tape, and plastic shielding.
Undid a wire bypass in the Orange/Black that was done for an unknown reason.
Cam sensor is new from the stroker build. Motor has under 10 miles on it, and it runs and sounds good. Good oil pressure, no overheating, idles at about 750, and the plugs are the color of lightly toasted bread.

The changes made a difference and seemed necessary, but the code is not gone permanently. In other words, what I did caused different behavior, but was not enough to remedy the problem...

TJ805

Hey buddy, I've been off line for a while. Oil pressure is no longer the issue since your lifter diagnosis. The rods and mains were changed and I'm certain that they were installed correctly. The motor reaches 210 and stays there with the electric fan kicking on shortly after.

97grand4.0

Hey just happened to see this. Good the pressure is ok. So the 1391. This is either the cam or crank sensor. This is a good read : https://autoservicecosts.com/obd2-codes/p1391/

Going back to your first couple posts,, that burnt connector sure looks like the culprit to me. This happens because the connection isn't good: loose, wet, etc. Most likely loose. The metal contacts are loose. When current flows through the loose connection it heats up the ..wait for it..resistance...and eventually burns it thus.
So the fix is to identify the wires involved, and jumper them around the connector, using wire nuts, crimp connectors, solder, etc. I prefer solder but wire nuts will work also. It just depends on which is easier to do with the space you have. Whichever you use they must be tight and waterproof to avoid the same thing.
That being said, the cam sensor would be my next culprit.

awg

try searching this forum...I am not 100% sure, but there was a dude a while back with a 40 page thread and I think that code was his issue

If so, it turns out the issue was the cam sensor, even though it had already been replaced

TJ805

Thanks, I'll check it out.
Nothing is off the table at this point. The mopar crank sensor I just bought was bad. We put the old one back and so far the engine light is off. I fixed several wiring issues and hope that was the issue. I'm not sure how long it takes for the codes to clear, but I'm hopeful that we've got it whipped. If not, I'll do the cam sensor. Do I have to replace the entire unit, or can I just buy the top part with the wires?

awg

here is the dudes thread

if you click on his username, there is also another thread from him on the P1391 code

I persoanlly would consider buying a new distributor whole, as the internal bush or gears can become worn, I have one,
and also a couple of used OEM Cam sensors that I purchased of a fellow that was getting out of XJs.

(He sold me 2 of almost every sensor for $40 the lot..a huge boon for fault finding, especially if one breaks down far from home)
https://www.cherokeeforum.com/f2/99-...update-251947/

TJ805

After replacing the crank sensor with a MOPAR, repairing 4 damaged wires and a splice, I was still getting the code. On a whim I put the old crank sensor back in and the engine light is now gone. I'm waiting for the codes to clear. I've driven about 30 miles and wonder how long this usually takes. Can't drive too much due to expired tags that I can't renew until it passes smog.

4x4jeepmanthing

many times the second start up can throw the CEL if somethings still wrong