Heart Transplant 89mj--93xj

My little toy for the last couple years has been a 1989 Comanche. 4.0 Auto with a 231tc. Last year I bought a 1993xj with quite a bit of body damage and robbed the axles out from under it. (d30-d44w4.88 locked)
This summer I'm considering pulling the engine/trans/tc and swapping it over to my MJ.

Comanche is a non-HO auto with a column shift to a 231tc

Cherokee is a 4.0HO auto floor shifter(duh) to a 231tc

The computer will have to get moved over, How much of the wire harness to I have to move over? And what other parts will I have to make sure get swapped. I plan on going with the floor shifter.

From what I understand you would need to swap the entire wire harness. I put a 93 motor into my 87 XJ and I chose to adapt it to use the older computer system. This seems to be the agreed upon easier way. I had to swap all the sensors, in some cases adapting them to the newer motor(I used a HO theromostat housing to hold the HO's temp sensor, and I had to tap a hole for the knock sensor). If you want to use the newer intake manifold and throttle body, you must adapt the Renix TPS to work with the HO throttle body, as the HO TPS works differently. This is the most involved adaptation, there are available kits to do this, but there is several ways to fabricate an adaptor, it will be obvious when you see how the sensors differ. The transmission flexplate must be used from the Renix system, as the crank sensor uses it. If you keep the HO flexplate, it will not start.

There is information on here about the swap, and I can answer questions. This will surely be easier than swapping all the wireing, and it has been said that the Renix computer system has advantages over OBD.

My suggestion would be to swap manifolds over to the newer engine so you can basically plug-n-"pray"

Johnnie Walker said:

My suggestion would be to swap manifolds over to the newer engine so you can basically plug-n-"pray"

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That would certainly make it easier. Keeping the fuel rail and injectors would also be a plus, it seems mine runs rich with the HO injectors. I just liked that bigger TB and nicer manifold.

Both vehicles are complete and running. So I'd pull the engine/trans/tc out in one complete unit. As for fuel. The MJ already has a fuel cell in the back with remote fuel pump and filter. If it all looks straight forward I'd even consider throwing in the Mopar Phase 2 cam upgrade for the 92-97HO.

It is certainly possible to pull engine/trans/tc all as one unit. If you'll be running the HO on the Renix system, however, you will need to separate the engine/trans to install the Renix flexplate. I didn't realize this until after I installed the engine/trans, so I had to pull it all twice.