[Leans93]

It took me a while being in school and working but its finally complete! I just wanted to share some of my experience for those who may do the swap in the future.

First I got a donor engine from a 93’ Cherokee. It was mostly a complete engine minus the flywheel. I got it home and started removing everything down to the long block. I was considering rebuilding the entire engine myself but didn’t have the time and there’s a local engine shop that has great prices on remanufactured long blocks so I took it down and swapped. I tried to make everything on the engine I could new. I got a new water pump, 136 Amp alternator, and many other things. I reused the air conditioning compressor, my 2.5L power steering setup, and the distributor. I had the intake manifold hot dipped and picked up a flywheel and had it resurfaced. I also used Simple Green and engine degreaser to clean all the parts. I painted most of the parts so it would look kinda pretty. The swap wasn’t that hard but I am mechanically inclined so that helped. The most time consuming part of the whole thing was locating the correct bolts for everything. I recommend if you do the swap to get a complete donor so you don’t have to make 30 trips to the hardware store to get bolts. Oh a good tap and dye set helps too.







Anyways I don’t want to bore you since there are 100’s of threads on the subject so I will share some tips and pictures. I purchased a 6 cylinder computer from a 91’ YJ ($100) and I did grab a junkyard wiring harness from a 91’ XJ ($35). I did not use the XJ harness in my swap I only used two of the injector plugs from it. I left all of my 2.5L wiring in place and marked it with tape to where it goes. Another tip is that all of the connectors are different so it would be hard to plug something back into the wrong place. Still faster and easier to label them. So after the new engine was in I took the two injector wires and spliced them into my original harness. Drill the holes in the correct location on your original bulkhead and just run the new wires in. This is where the donor harness came into play as its wires already had the correct fittings to slide into the bulkhead. The FSM for 93’ shows that the only differences in the 4.0L and 2.5L harnesses is the addition of the two injectors and the subtraction of the power steering sensor. Using this process I saved tons of wiring headaches. I plugged in the two new injectors and then just plugged everything else in where it went before. The plugs and connectors for both 2.5L and 4.0L YJ’s are the same. I did have to extend a few of the wires. Hopefully this will help folks because most of the write-ups gave me headaches when talking about the wires and this was seriously headache free.

[Leans93]

Another thing I did was replace the XJ alternator bracket with the one from my 2.5L (same part number as the one for the YJ 4.0L) I did have to purchase the lower bracket from the junkyard as it is different from the 2.5L. This got rid of the XJ’s off center fan pulley. I was switching to an electric fan anyway so I didn’t need this. Also the 136 Amp alternator requires grinding to fit on the XJ bracket whereas it bolts right up to the YJ’s. Also a lot of folks have clearance issues with their Taurus fans and the YJ fan bracket. My next tip can be used for any 4.0L Wrangler swapped or stock. I kept the XJ water pump as it has a short pulley on it. It gives about an inch to an inch and a half extra clearance as there is no nub where the manual fan used to be. There are a few threads that say you can’t use the XJ water pump due to reverse rotation or something. This is false at least for the 93’ XJ. It is not reverse rotation and works perfectly.





The Taurus fan came from the junkyard and installed easily as other posts advise. I have a picture of my relay setup. I ran it to a switch in the dash for low high and off. I was going to use a temp switch but it’s not really needed so I skipped it. It will always be on low unless I turn it to high or off using the switch. Again the retention or for those of you the swap to an XJ water pump and pulley will give you that extra room you may be looking for.





Some pics of my motor mounts moved and welded with support brackets made from some scrap I had laying around.



I also picked up a remanufactured AX-15 and put a B&M short throw shifter on it. I purchased an AX-15 transfer case shifter off ebay that said it was for this application but I still had to do some grinding on it to get it to fit. I did a little removal of some rubber and metal to get the shifters to fit in the tub but didn’t have to cut the tub!





I changed my transfer case input shaft to the 23 spline and added a JB Conversions SYE on the back. Changed the seals and the chain looked good. Got a CV drive shaft from a local shop and some shims to correct the pinion angle.



If anybody has any questions please feel free to ask!

My baby is running like a Cadillac now! A Cadillac on steroids!

[Joe Dillard]

Nice!

I nominate this for TOTW (thread of the week).

[MUDDYJEEP]

Very cool - I'm close on finishing the same swap. What fan shroud did you go with? Was thinking of cutting down the one from my 2.5l - It has the p/s resovoir attached to it which looks like it should work (I think this is what you described) Out of curiousity, what tranny mount bracket did you go with? I ended up fab'ing one

Clean job there-

[Leans93]

Thank you guys!

I used a Taurus electric fan so I just used the shroud its enclosed in.

I bought a stock transmission bracket from the dealer.

[jeepsurf]

nice job.

[Alvy]

Great work Leans. I'm in the countless hours of research and parts gathering phase now of my 8.8 swap for my 93. Seems like you really did your homework and gave out some really good advice to others planning this swap that may not have been out there. I'm glad that people are so willing to share their ideas about what works and what doesn't. By the way, what time frame did you do this in start to finish?

[Jeepsr4me19]

Where did you put the other 2 wires for the injectors? They go to the PCM?

[Futaba]

wow thats really nice, i wish i saw this before i did mine. i hacked mine pretty bad but it only cost me $300 for everything.

[capone1680]

Nice write up.

[texas_yj]

I take it that the fuel injectors are not sequential, does the computer batch fire them, or is it set up morelike a throttle body with multiple injectors? if its batch timing, do you have to worry about which set of injector wires you connect to? just currious, I like to know how things work

[ritjobbie]

Originally Posted by texas_yj

I take it that the fuel injectors are not sequential, does the computer batch fire them, or is it set up morelike a throttle body with multiple injectors? if its batch timing, do you have to worry about which set of injector wires you connect to? just currious, I like to know how things work

+1 Me, too! Inquiring minds want to know.

[Canfourjeep]

How did you splice the other injector wires and make them work?

[Leans93]

Each injector has a specific location in the bulkhead as to where it is located. I'm not sure if Haynes manuals show the diagrams but I used my FSM to find these locations. So yes you must place the wires in a specific location. Now the beauty of it is that all of the 2.5L bulkhead locations are the same as the 4.0L so there is no need to mess with any of the other wires. The first four injectors 1 through 4 are in locations 13, 14, 15, and 16 respectively. Those 4 you don't need to touch. Injector 5 is located in position 38 and injector number 6 is in position number 58. They must be in these exact locations.

On the bulkhead on each end you will see a number stamped in the plastic. This corresponds to the wire directly near the number. This helps locate the bulkhead point. I'd print it but its copyrighted material. Mods can I do it if I site where its from? Anyways the bulkhead wires have special fittings on the end to keep them in the harness. You take a screwdriver to the front plastic piece holding the wires in near the edges. There is a tab on the front that the screwdriver fits in and this plastic retainer pops right out.

Take the entire wire from your donor harness and cut it near the bulkhead end. Once you have located the correct position on the bulkhead drill a small hole in it. Be careful here because if you drill a hole thats too big the connector wont stay in. I used a 1/16 drill bit which was a little small but not much bigger than that. Then I ran the cut wire through and replaced the piece of plastic that holds the wires in their locations. I then reconnected the wire and ran it down the top rear of the engine with the other wires that were already there.

For the ground end of the injector wires I followed the other 4 ground wires from the other 4 injectors. Just inside the large wire loom the all connect to one another and then one iwre runs off to a ground somewhere. I didn't follow it any further cause there is no need. I just took my new injector plugs and spliced one each into one of the old injector ground wires. taped it and recovered it with conduit and was all set.

Here you can see the red plastic that holds all of the connectors in place. On the upper right side is where you insert a tool to remove this piece. As you can see I kinda messed this one up. Be careful with this plastic piece because you have to reuse at least one of them.



Here the plastic is removed and you have acess to all of the wires. I used a pick and small needle nose pliers to get the wire out.



Here you can see one wire pulled. Notice the metal connector on the end. These are very soft metal and very damage prone. If you do happen to break one you have a whole harness full of them so don't worry.

[fyrdriver]

I'm glad you did this write up. I always wondered about just adding the two injector wires. My manual(I think Chiltons) also shows the only differences as you listed.
Looks good, your ready for another 200K miles now!