JK Pentastar Swap
JK Enthusiast
Joined: Dec 2011
Posts: 185
Likes: 0
From: Quebec
ok so I'm working on that a bit tonight.
fixed the inverted windshield washer by switching the wires 21 and 25 in C3 (the green one) connector on the tipm.
Removed the console, and the dynamic sensor harness is the original, unplugued and checked the voltages and everything is ok on that side. gotta check somewhere else.
I don't remember if you replaced your ABS module too? I'm asking because at the dealer there is a reinitialisation procedure that could maybe fix the trac control light. The tech has to go on a road test with the laptop plugued in and do a couple manoeuvers in order to complete the reinitialisation. I'll talk to my old partners monday about that.
I'm jumping on the fan issue.
fixed the inverted windshield washer by switching the wires 21 and 25 in C3 (the green one) connector on the tipm.
Removed the console, and the dynamic sensor harness is the original, unplugued and checked the voltages and everything is ok on that side. gotta check somewhere else.
I don't remember if you replaced your ABS module too? I'm asking because at the dealer there is a reinitialisation procedure that could maybe fix the trac control light. The tech has to go on a road test with the laptop plugued in and do a couple manoeuvers in order to complete the reinitialisation. I'll talk to my old partners monday about that.
I'm jumping on the fan issue.
JK Enthusiast
Joined: Dec 2011
Posts: 185
Likes: 0
From: Quebec
Great news! afterall, my bud kept the original harnesses so I recycled the cooling fan relay and wires. plugued in the C3 tipm connector and its works 90% correctly, lol.
My friend didn't want to keep the A/C so we haven't installed the A/C line. And the result of this is that Key on Engine off, the fan runs at low speed. It always runs at low speed. I studied the diagrams and the logic that controls de low speed relay is internal to the tipm so I have no way to cheat on that. When the pcm have no data from the high pressure sensor it will actuate the fan as a protection. If it doesn't,(in a working system) the temperature would rise too high, creating very high pressure in the condenser which could make it blow, or the lines blow, or.. whatever.
Luckily he also kept the a/c lines in the garage attic so I will plug the sensor tomorrow and keep working on that and a few other things that have to be done to call it over!
Also, I've talking to my old partners at the dealer about the trac control light, and there is a PCM replaced, ABS replaced, and ABS reinitialization that could be tried in the ABS module.
My friend didn't want to keep the A/C so we haven't installed the A/C line. And the result of this is that Key on Engine off, the fan runs at low speed. It always runs at low speed. I studied the diagrams and the logic that controls de low speed relay is internal to the tipm so I have no way to cheat on that. When the pcm have no data from the high pressure sensor it will actuate the fan as a protection. If it doesn't,(in a working system) the temperature would rise too high, creating very high pressure in the condenser which could make it blow, or the lines blow, or.. whatever.
Luckily he also kept the a/c lines in the garage attic so I will plug the sensor tomorrow and keep working on that and a few other things that have to be done to call it over!
Also, I've talking to my old partners at the dealer about the trac control light, and there is a PCM replaced, ABS replaced, and ABS reinitialization that could be tried in the ABS module.
Thread Starter
JK Newbie
Joined: Aug 2015
Posts: 53
Likes: 8
From: Fairfax, VA
I did replace the abs module. I just unbolted it, slid it off, and replaced it with a 2013 to match the engine. I never programmed the VIN into the new ABS module, so if you pull up diagnostics, it will show a VIN mismatch error, but in 15,000 miles of driving, it hasnt thrown a dash light or error code, and the ABS works great.
JK Newbie
Joined: Apr 2018
Posts: 2
Likes: 0
From: Rogue River, Or
I got a 48 Willys v8 rockcrawler on tons, NV4500 and 42s and now also a mint 2007 Rubicon with 92k on the sorry 3.8.....
So I have read the entire thread, but was a little unclear on 6 spd NSG370 transmission compatibility so I went to mopar parts online and verified the 2007 & 2008 use the same part numbers. I also looked at the engine bay wiring harness which is available there for $ 215 ! so with a little luck I will also be heading down this road probably next summer?
So I have read the entire thread, but was a little unclear on 6 spd NSG370 transmission compatibility so I went to mopar parts online and verified the 2007 & 2008 use the same part numbers. I also looked at the engine bay wiring harness which is available there for $ 215 ! so with a little luck I will also be heading down this road probably next summer?
Thread Starter
JK Newbie
Joined: Aug 2015
Posts: 53
Likes: 8
From: Fairfax, VA
The 6 spd is exactly the same from 2007-2017, so that wont be a problem. The wiring harness may or may not work. The PCM is upgraded on the Pentastar, so I couldnt use the 2013 harness out of the box, I had to splice it. Its definitely possible, though, and not nearly as bad as you might expect.
JK Newbie
Joined: Apr 2018
Posts: 2
Likes: 0
From: Rogue River, Or
The 6 spd is exactly the same from 2007-2017, so that wont be a problem. The wiring harness may or may not work. The PCM is upgraded on the Pentastar, so I couldnt use the 2013 harness out of the box, I had to splice it. Its definitely possible, though, and not nearly as bad as you might expect.
JK Newbie
Joined: Nov 2019
Posts: 1
Likes: 0
From: San Diego
Hey guys so I know this thread is dead lol but i have a little birdy that tells me RPM Extreme is working on a 3.6 conversion kit to for 07-11s. Might make it a lot easier to convert, but it might be a little more than 3k like Saharacon was able to do. IDK many details but I thought y'all might like to hear that lol
JK Newbie
Joined: Jul 2019
Posts: 52
Likes: 16
From: Central USA
I am new to the group, but I am almost finished with swapping out my 187,000 mile 3.8l engine in my 2008 JKU with a 2013 3.6l pentastar and I thought others may like to hear about the experience. Originally I wanted to buy a new JKU, but the dealers in my area wanted $2k over MSRP, so I said no thank you. I decided to buy a very good condition high mileage 2008 Sahara and do a hemi swap, since many Hemi kits were advertised as "complete" for ~$5k. Only after I did some more investigation did I find out that "complete" means no engine, no transmission, and missing about $5k in parts you need to buy from the dealership. As I began to consider other options I could afford, I evaluated VW TDI engine swap (cody), LS engine swap (many kits), Hemi swap, but no one had done a pentastar swap... I called several dealers and expert engine swappers (AEV, Novak, Motech, JSS, and many others), and they all told me it was almost impossible, stupid, and even if I could get it to work I would have endless problems such as emissions and communication issues. Being a mechanical engineer, and a bit bull headed, I decided to throw down the gauntlet and see if I could get it to fit (mechanically and budget-wise).
Last edited by JEEPPIE; Nov 28, 2019 at 01:37 PM.
JK Newbie
Joined: Oct 2020
Posts: 1
Likes: 0
From: NYC
did the 3.8 to 3.6 swap work
I am new to the group, but I am almost finished with swapping out my 187,000 mile 3.8l engine in my 2008 JKU with a 2013 3.6l pentastar and I thought others may like to hear about the experience. Originally I wanted to buy a new JKU, but the dealers in my area wanted $2k over MSRP, so I said no thank you. I decided to buy a very good condition high mileage 2008 Sahara and do a hemi swap, since many Hemi kits were advertised as "complete" for ~$5k. Only after I did some more investigation did I find out that "complete" means no engine, no transmission, and missing about $5k in parts you need to buy from the dealership. As I began to consider other options I could afford, I evaluated VW TDI engine swap (cody), LS engine swap (many kits), Hemi swap, but no one had done a pentastar swap... I called several dealers and expert engine swappers (AEV, Novak, Motech, JSS, and many others), and they all told me it was almost impossible, stupid, and even if I could get it to work I would have endless problems such as emissions and communication issues. Being a mechanical engineer, and a bit bull headed, I decided to throw down the gauntlet and see if I could get it to fit (mechanically and budget-wise).