swaping out renix for 96 computer system

im swaping a HO 4.0, trans np 231 and the computer system out of a 96 into my 1988 xj with a renix non HO 4.0 and np 242. i would like to keep the old wiring for like the horn, head lights tail lights, indicators, ignition, basicly anything that dont have to do with the motor and trans. On my other jeeps iv made motor control harnesses from scratch with no problems. (im a low voltage electrician) From doing that iv seen that mostly all the wires for the motor and trans are in the motor compartment besides like the tcm that goes into the cab and like the wires for the obd2 connector. im wondering if i can swap out all my old motor harness and when i swap in the new motor swap the newer harness in with out having to swap over all the wire harnesses in the truck (lights horn ignition so one and so forth). In the 96 im cannibalizing where the harness goes into the firewall it connects to the fuse panal, are any of the circuits in that fuse panal used for the motor controls? i kept the motor harness on the 96 all together with the fuse panal and relay box connected with the main battery cable and everything. i know that will have to go in with the newer motor. if anyone has swap out a renix system and could give me some things to look for that would be great. i hope i have this posted in the right forum also haha thanks for the help guys

Wanna do it the easy way or are you dead set on the OBD system?

whats the easy way? i would like to get rid of the renix something is up with mine. ill be on the highway cant go over 60mph foot to the floor with the trans power button on and my rpm's will never go over 2000

Easy way is to keep the rEnix, but I see you're not inclined to do that. Sure your catalytic converter isn't clogged? Ever run a vacuum test to verify?

never vacuumed tested just took it wheeling a few weekends ago and messed up my front locker, drove fine on the way home but then last weekend i started it up for the first time since wheeling and the motor is stalling sounds like its not getting enought air some how, kinda smells like theres alittle gas in the oil. i didnt know i could run a HO 4.0 on the renix

HO is not magic. It stands for Highly Overrated.
Here's the easy way.

Cruiser’s HO into Renix Swap
This swap is easier than some will lead you to believe, generally those who have never done it. Those of us who have done it, like myself, will share with you the things that need to be done for a successful swap. Just think of it as swapping in a long block.
The HO and Renix have some differences but none that can’t be overcome very easily.
Any HO engine from an XJ or ZJ through 1999 can be used. One running change was that the rear of the head was no longer drilled and tapped for the temperature gauge sender beginning in the 96 model year. The sender can be relocated to the threaded hole in the thermostat housing taken from the HO engine. You’ll have to extend the wire to that location. Some brave souls even drill and tap the HO head for the sender.
You will be using the intake and exhaust manifolds from your Renix, along with all your sensors and wiring. Since the intake ports of the HO are slightly different, you use the Renix gasket. Exhaust ports are identical.
You will need to use your Renix distributor as it is different than the HO because they use different fuel management systems. The flywheel or flexplate from the Renix must be used so your CPS gets the correct signals. The valve cover from the Renix allows you to keep your CCV system intact and requires no modifications.
The HO block will have a plug in the coolant galley on the driver’s side of the block, closest to the front, which needs to be removed so your Coolant Temp Sensor can be installed in it’s place just as it is on the Renix. It requires a 5/16" square drive or a modified 3/8" drive that has been ground down to fit. Do this before installing the engine.
As for the knock sensor, which is located just above the oil pan on the driver’s side of the engine about mid way, all the blocks I’ve seen are threaded for it. If not, I’ve heard they may be drilled but not tapped. Tap the hole if that’s the case.
　
Revised 03/28/13
　

i guess your recomending to stick with the renix. i see that is much easyer and i think i might just do that only because i have a messed up motor in mine now and im already half way down tearing my parts truck. i am going to rebuild the 96 motor myself, this will be my first rebuild and swap. iv swapped 4.0s before and there easy just never rebuild a motor got any advice on that?

Hard to advise on building a motor. Do you really need to?

the 96 has like 250k on it and i dont know how well taken care of the jeep was. i know the trans is shot but i have a working trans from a 96 with 140k on it. and sence the trans in this jeep is done who knows whats wrong with the motor. im alittle upset my motor in my 88 isnt working right, im the third owner of this jeep and it only has 123k orignal miles on it. i have no idea what happened to it. it was running fine when i drove it last then i go and start it up and its not running right sounds all bogged down wont run without me giving it gas and even then it struggles i have no idea what happened. i didnt suck in any water didnt hit anything well didnt hit anything really hard a few trees here and there with the bumper when the trails got really tight.

I'd be diagnosing that old rEnix motor and making every effort to keep it. Now that should be the easiest route.

i dont know anything about the renix or even the first place to start with it.

njxj4x4 said:

i dont know anything about the renix or even the first place to start with it.

Click to expand...

I do. If you wanna keep it, let me know and I'll guide you through it. Unless there's something major with the engine, and that's usually accompanied by loud noises, it shouldn't be hard to do. There's some groundwork that needs to be done right off the bat.

Got a multimeter? a vacuum gauge?

with the low miles in the renix i would like to keep it, gonna be alot less work to do. haha yes i have a multimeter, and know how to use it. i can get a vacuum gauge. its not making any loud noises dont even have the famous 4.0 tap yet also. and even with we find out something major wrong with it i would be willing to pay the money to rebuild this motor then the 96 one only cause i could prob get away with out having to get it machined maybe just a honeing because of the low miles. if you could help me with it i would greatly appreciate it.

Click below. Do 1, 2, 3, 4, 5 and 7.

How are your plugs wires cap and rotor?

http://www.cherokeeforum.com/f51/cruiser54s-mostly-renix-tips-153657/

plugs wires and cap are brand new even silaconed around the bottom to keep water out. rotor is prob the orignal from 88 haha. i do know the renix motors had a bad grounding system, buy the privious own did go into it and fix all the grounding points put a better thicker grounding ribbon wire in and all that good stuff. i have recites from it being taken to the shop out in bumf**k PA to get the wiring redone or fixed or something

Don't trust the PO. Do it yourself.

ill get on that this weekend. i wanted to go into it and clean all the connectors also make sure there connected. my buddy was telling me to take my belt off and run it just alittle to see if it still makes the noises its making, i dont know about that tho. im gonna go out and get a vacuum gauge too

njxj4x4 said:

ill get on that this weekend. i wanted to go into it and clean all the connectors also make sure there connected. my buddy was telling me to take my belt off and run it just alittle to see if it still makes the noises its making, i dont know about that tho. im gonna go out and get a vacuum gauge too

Click to expand...

Excellent plan.

have not been able to get anything done this weekend been pouring all weekend here