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Gr8Dain's 4.0/aw4 swap from a 97 XJ

gr8dain

gr8dain

Old and Slow
Lifetime Member
SOA Member
City
Ashburn
State
VA
So I ran into more issues with my 258 and decided to swap it out for the 4.0. I picked up a 4.0 with aw4 and transfer case from a 97 XJ. I will get it later this week.

I tried looking for Eric's thread on the topic, but did not find a build post, so Eric, if you have the link, I would greatly appreciate it. I am just starting all of my research. Right now,. I am looking for the wiring harness, ecu and auto tranny controller for the 97 combination I am picking up. This is a daunting task for me (the full swap, not the searching for parts). It did not happen at a great time. Sniper went on in January, loving it. I just installed a dana 300 with 4 to 1 gearing and twin sticks. I have yet to use them, and I want to keep them, so I will need to see if the clocking ring I have can be used with the aw4, or if I need to get a different clocking ring.

In any case, I know this is a relatively common swap, and I know 2 local friends (Rick Milam and Dave Plummer) who have done on (one OBD2 and one OBD1). They will be helping me and I am grateful for that. At least until I wear out my welcome with them,

I will be posting my progress here, but please feel free to chime in with input at ay time. And helpful links will be appreciated. I think Rick may have found a wiring harness for me to use, but if not, then I will look at Hesco. I am not good with wiring, but hopefully Rick and/or Dave can help me with that part.

And I don't know if I want to sell the sniper or install it on the 67 Impala my son has. He does not want it, but I hate it sitting on a shelf.
 
I plan to do a '96 xj computer 4.0/aw4 swap in the not too distant future. If you find out how to get the check engine light to work without the dash module I'd be all ears.

I have a stock wiring harness I am reworking for the swap. I am in the process of depinning the ecu connectors.

Also plan to have the 4.0 rebuilt with a 258 crank. Once I take the block to the machine shop I'll know what overbore is required.
 
Before I read your whole post, i was thinking, "Is he gonna sell the sniper?".....interested here.
 
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I have a complete 1995 XJ under dash, under hood harness with AW4 controller intact, shifter, etc. for my "someday" project. Took everything I could.
 
Rosco1974 said:
I have a complete 1995 XJ under dash, under hood harness with AW4 controller intact, shifter, etc. for my "someday" project. Took everything I could.
Click to expand...

I wish the seller of this motor and trans would have been smarter. He got rid of the donor XJ without grabbing the ecu, trans controller or the harness.
 
If there is a LKQ or "you pull it" nearby, you should be able to source what you need fairly cheaply. I did a similar (but GM) swap that was OBD1. Honestly, sorting out the harness took more time than installing the drive train. I started with the mindset of going pin by pin removing anything unneeded. I finished by only addressing wires not connected to anything. Both methods work.

The factory GM harness starts at the alternator on the drivers side, the runs across the front of the engine to the passenger side, then straight to the back of the engine. After the loom is at the back of the engine it splits, one side going to the ECU then the other to connect to the Jeeps harness. In hindsight, I should have sorted the harness out completely before placing in the Jeep. Access to the wiring harness is pretty difficult at the rear. Hopefully with the I6, you will have easier access to the harness
 
On my LS swap, I have completely stripped the factory harness. Individually zip tied each wire with the circuit description and ECU pin number. I then plugged the factory connector into the engine sensor/actuator to ensure I would not forget where they go.

Once it is in the jeep I will custom route the harness in the most logical manner. It probably won't be the same as the factory.

GM LS Egine.jpeg

For my 4.0 swap, I will be doing the same thing, except it won't be stored on the donor engine. Mostly because the wiring harness came from a different vehicle and I never had the opportunity to unplug all the sensors/actuators. So I will be learning as I develop the proper harness routing on that install.
 
gr8dain said:
So I found Eric’s thread on his rebuild and am linking it here so I can easily refer to it. Wow. That thread was very informative. And scares the crap out of me. Am I in over my head? I hope not.

https://www.cj-8.com/threads/postal-going-4-0-aw4.23251/
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Looks like a nice step by step guide. Even the same 4.0 motor.

What could possibly go wrong? :rotfl:
Between your local help, this guide, and this virtual family (not necessarily in that order) I think you've got this. :popcorn:
 
FLCJ8 said:
Looks like a nice step by step guide. Even the same 4.0 motor.

What could possibly go wrong? :rotfl:
Between your local help, this guide, and this virtual family (not necessarily in that order) I think you've got this. :popcorn:
Click to expand...


I hope so. And I hope it does not take forever. I will want the Scrambler back up and running soon.
 
I plan on picking up the motor and trans this weekend. Hopefully I can fit it in my garage. I am also motivated to start taking the Scrambler front end apart. But since I cannot store it in the garage (has the 3a in it and that won't stay outside overnight), I need to keep it looking like a complete vehicle as long as possible, so the fenders need to stay on as long as possible. Hopefully I can work with the fenders on. I know I will remove the grill at the time I pull the old motor. Just not sure how much I want to start tearing things apart without having a lot of the needed new parts. Dang it. I need a pole barn on some property.
 
I'm kinda in the same predicament as you, engine is built but still need to overhaul/ go through transmission and D300 upgrades. Doing it in a 1 car garage. Waiting for hurricane season to be over before tear down, don't want to be caught with my Jeep pants down and get flooded or wiped out. Main difference is mine is running, I'm just hoping I'm not down for months either
 
Used the crappy F250 to go get the motor and tranny. Made it there and back home without issue. I also cleared out what I could from the garage to make room for this and the parts I take off the Scrambler and order for this one.
A3EA4ED9-34F7-4611-A85F-CF21344334C7.jpeg
 
Starting to disassemble as I have time today while working from home. So pre-work time included removing the bumper and winch. Things learned are: I need to secure my front bumper better. And I need new grade 8 bolts for that and the winch plate.

My plan is to remove the grill, radiator, lights and all as one piece. And even though I won’t be reusing the harness, I am planning on labeling every wire I disconnect. I especially want to label the sniper wires as I have a feeing I will be selling that. :cautious:
1E69A466-25F7-473E-9553-6754B36CF583.jpeg
 
Hmmm. While the grill is out, do I want to paint it? It is currently a gray that was the color of the Cj that I got it from. I will have to think about that.
 
You may already know this... You can loosen the bolt on the harness bulkhead/pass though. Once removed, you can un-clip the horn, headlights, blinkers and such from the main harness block. Makes it much easier to remove the entire front clip as one unit.
 
sdsupilot said:
You may already know this... You can loosen the bolt on the harness bulkhead/pass though. Once removed, you can un-clip the horn, headlights, blinkers and such from the main harness block. Makes it much easier to remove the entire front clip as one unit.
Click to expand...

Dang, I didn't know that... I unplugged everything and slung the wiring over my driver side mirror. :banghead:
 
sdsupilot said:
You may already know this... You can loosen the bolt on the harness bulkhead/pass though. Once removed, you can un-clip the horn, headlights, blinkers and such from the main harness block. Makes it much easier to remove the entire front clip as one unit.
Click to expand...

I thought about it. But since I am replacing the harness anyway, for now I just undid all of the lights and bagged that section of the harness and have it hanging by the master cylinder.
 
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