Novak Conversions Jeep Wrangler TJ engine mounts

Engine harness issues

Daytonbuzzman

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Original poster
Joined
Apr 6, 2023
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Location
dayton ohio
I have a 2005 LJ, 4L auto with 51,000 miles. I have had it for about a year and a half, and put about 4,000 miles on it. Its my first jeep. I am by no means a mechanic, but can do basic repairs, brakes, plugs , o2 sensors, ect. With that being said I will try to describe the issue as best as possible in detail.
Jeep developed a leak at transmission cooler line at the radiator. I tried to change cooler line but it was froze on the radiator end. Took it to a local shop and he replaced radiator and lines.
Last Aug went mudding at Jeep Jam in Ohio. On the way home got flashing check engine light. Had it towed to same shop that replaced radiator. He replaced crankshaft position sensor. Not sure of codes. Ran ok for a while, check engine light came back on. Same shop replaced bank 1 sensor 1 and bank 2 sensor 2. Check engine light again came on. By now I had started educating my self. Took it back to same shop. He said he should have changed all 4, I asked him if he used ntk on first 2, He didn't. I requested he use them for the bank 1 sensor 2 and bank 2 sensor 2. Ran good for a while. Flashing check engine light came back. I have a cheap code reader and pulled up codes p0137, p0139,p0339, p0157 and p0158. I went ahead and changed out all 4 o2 sensors myself, and the crank sensor with NTK sensers. I did this because I wasn't sure what the mechanic put in there, I know a one was a Bosch. Again, Check engine light, limp mode ect. After reading posts on here I contacted Mark at Wranglerfix, and bought a new computer and put it in. Same issues. Now I am thinking short in wiring harness. Took jeep to a different mechanic who specializes in jeeps at Exuberant 4x4. He saw that original mechanic replaced transmission cooling line with a rubber hose and hose clamps. Transmission fluid was dripping on bank 2 sensor 2, he thinks that was issue causing a short. Changed sensor again, and put on the correct transmission cooler lines. Still getting p0138 and p0158. Weird thing is after resetting codes, they only reappeared when outside temperature was hot, I drove it all morning, as soon as the outside air temp went up check engine light came back on with the p0138/p0158. Talked to Jay at Wrangler Fix, he seems to think issue is wiring harness. He did offer to check computer if I sent it back, but I put back old computer and same codes. Guys at Wrangler Fix were great. Exuberant 4x4 checked wiring harness with a wand. He didn't find any broken wires, but some could be touching inside harness. so, we are thinking transmission fluid wicked up in the harness. I had read you can run jumpers from the sensors up to the pcu, and bypass the problem. He said he would but he didn't like that idea. I know he's a good mechanic, and does good quality work, and I trust his judgement. So my question is has anyone ever run jumpers? I don't think I want to go that route, unless it will work. But that might lead to future issues. Grant, the mechanic at Exuberant explained that replacing the harness is time consuming, if you can even find one. I don't want to buy a used one.
My next question is there a place that sells new ones? I know on one of the posts WranglerFix mentioned they will be doing this soon, but the website didn't say anything.
Next question is if the issue area is accessible without removing harness, is it possible to repair while in the jeep? That still leaves the question how much more of the harness is contaminated. I feel confident in patching the harness, but not removing or reinstalling. I appreciate any help or thoughts or suggestions.
Thank you
 
You can label all the connectors on the harness and then on the engine and transmission and then you'll know where everything goes. I color coded mine so it was easy to see where something went.

I also bought a used harness (to the tune of $650), but mine was for a transmission swap on an '05. The harness part is pretty straightforward but takes awhile to make sure you have the right routing. I don't know of any place that sells new ones, yet, as you mentioned WF is talking about offering them.

It's a good idea to re-loom your harness anyway. This might be the time to do it. Sorry this is probably not much help.
 
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You can label all the connectors on the harness and then on the engine and transmission and then you'll know where everything goes. I color coded mine so it was easy to see where something went.

I also bought a used harness (to the tune of $650), but mine was for a transmission swap on an '05. The harness part is pretty straightforward but takes awhile to make sure you have the right routing. I don't know of any place that sells new ones, yet, as you mentioned WF is talking about offering them.

It's a good idea to re-loom your harness anyway. This might be the time to do it. Sorry this is probably not much help.

It was a lot of help. I had thought about labeling each connector. Just seems like its a daunting task. It seems like overnight I turned 65 years old, and put on the weight. Pretty sure I can't crawl around under cars like I used to be able to. Thank you for your advice.
 
Novak Conversions Jeep Wrangler TJ engine mounts