FireFighter32 Posted September 14, 2009 Share Posted September 14, 2009 I have a 1989 Jeep Comanche with the 2.5 I4. I also have a parts 1994 Cherokee for parts which has a 4.0HO. What is involved with the switch from renix to HO? I know I'd need to swap computers, but what else? Also what will need to be done in order for me to pass CT Emissions with a different motor in the vehicle? Link to comment Share on other sites More sharing options...
Pete M Posted September 14, 2009 Share Posted September 14, 2009 plan on swapping absolutely everything from the Cherokee, including the wire harness. :thumbsup: Link to comment Share on other sites More sharing options...
Eagle Posted September 14, 2009 Share Posted September 14, 2009 Call the emissions station you use and ask what rules will apply. In some states, your vehicle is tested according to the year on the VIN even if you swap in a newer engine. In other states, if you swap in a newer motor you have to meet the emissions for that year. Plus you're going from a 4-cylinder to a 6-cylinder. My guess would be that a 1994 4.0L will pass the emissions for an '89 4-banger with no problems, so maybe you don't have to say anything. I don't think they open the hood -- I believe they just verify the VIN, stick the sniffer in the tailpipe, and run it up on the dyno. Oh, and the gas cap pressure test. Link to comment Share on other sites More sharing options...
kro10000 Posted September 14, 2009 Share Posted September 14, 2009 well i know on tjs that the engine mounts on the 2.5 are mounted in a different location then the 4.0 so plan on doing some fabrication Link to comment Share on other sites More sharing options...
mjeff87 Posted September 14, 2009 Share Posted September 14, 2009 The frame horns on XJ/MJ's are bolted on (not like TJ's that are welded). You'll need a set of 4.0 horns, the bolt holes/studs are there already so you can just bolt them in. 2.5 engine mounts look very similar to 4.0 ones but won't work...you'll need 4.0 ones. Couple other things that are different, aside from all the wiring: -throttle cable -radiator (remove the 2.5 radiator shroud brackets and the 4.0 one drops in) -coolant overflow bottle of some kind for open system (I reused the 2.5 one but had to modify the wiring harness on the driverside fenderwell and eliminate the EGR solenoid) -cover plate on transmission tunnel above shifter -fuel lines, you'll have to splice the 2.5 ones into the 4.0 fuel rail (I used rubber fuel line, some barbed fittings and clamps) -fuel pump (you need a 4.0 one, runs at a higher psi) Have fun :D Jeff edit: disregard the coolant overflow bottle.....you can use the stock HO one out of your XJ. I couldn't use the HO setup on my renix swap because of the way the overflow mounts by the coil area, that's why I reused the 2.5 one. Link to comment Share on other sites More sharing options...
FireFighter32 Posted September 15, 2009 Author Share Posted September 15, 2009 So for my complete motor swap I will need the following off my parts Cherokee. Correct me if I am wrong. -Motor -Computer -Wiring Harness -4.0 Horns -4.0 Motor Mounts -Throttle Cable -Radiator -Coolant Over Flow Bottle -Cover Plate on Transmission Tunnel above Shifter -Fuel Lines -Fuel Pump Am I missing anything? Link to comment Share on other sites More sharing options...
mjeff87 Posted September 15, 2009 Share Posted September 15, 2009 by wiring harness, we mean the COMPLETE harness both underhood and interior. Since you're using an XJ donor you'll also have to splice in the MJ sub-harness in the cab that feeds the rear lighting circuit and fuel pump (MJ is slightly different than XJ in rear lighting circuitry). Your list is pretty much complete, though. I'd suggest you strip the MJ engine bay bare first, then swap the XJ harnesses in and start transferring everything from under the XJ hood into the MJ. Jeff Link to comment Share on other sites More sharing options...
FireFighter32 Posted September 17, 2009 Author Share Posted September 17, 2009 Ok so you guys say I need to swap the 4.0HO fuel pump into the Comanche. No is that the in tank pump? Also would I need to do all new fuel lines tank to motor? Or can I use the same lines? Link to comment Share on other sites More sharing options...
FireFighter32 Posted September 20, 2009 Author Share Posted September 20, 2009 Also will the 4.0HO fuel pump fit in the stock gas tank? Link to comment Share on other sites More sharing options...
bentnotbusted Posted September 20, 2009 Share Posted September 20, 2009 You don't mention what transmissions you're dealing with, you'll need the 4.0 trans as well. This will also require the driveshafts be changed. The front one from the XJ will work but you'll need to find one for the rear or have your current one modified. As for the fuel pump, the entire XJ sender will not fit the MJ tank but I think you should be able to swap just the pump. Link to comment Share on other sites More sharing options...
buddy208 Posted September 20, 2009 Share Posted September 20, 2009 i doing the same swap and your going to need just about everything from the cherokee, when we were done with the cherokee it was just a tub and now i just having trouble with the tail lights wiring up the xj to the mj tail lights but it was an easy swap for most of it. Link to comment Share on other sites More sharing options...
FireFighter32 Posted September 24, 2009 Author Share Posted September 24, 2009 I am swapping in a 4.0 HO, AX-15, and NP231, all out of the same 1994 Cherokee Link to comment Share on other sites More sharing options...
FireFighter32 Posted October 22, 2009 Author Share Posted October 22, 2009 So I have another question about this swap. Do I need the interior fuse block out of the Cherokee? Or does the Renix Comanche fuse block work with the HO? Link to comment Share on other sites More sharing options...
WBKrazy Posted October 22, 2009 Share Posted October 22, 2009 when they say ALL wiring, they mean it lol..... you need to strip everything out of the cherokee and transplant it into the mj... the fuse block is part of the interior harness.. Link to comment Share on other sites More sharing options...
JeepcoMJ Posted October 22, 2009 Share Posted October 22, 2009 engine trans transfercase engine wiring engine bay accessories radiator (you already have a 4.0 rad support so long as the MJ is 87+) computer(s) fuel lines fuel pump (sending unit needs changed) all dash accessories, heater box if you want the a/c to work/if you have it, dash wiring shifters. then you need to add in a brake light wire on the dash harness and splice everything for the rear lights and fuel pump. Link to comment Share on other sites More sharing options...
JeepcoMJ Posted October 22, 2009 Share Posted October 22, 2009 oh, wiper motor too and headlight harness. Link to comment Share on other sites More sharing options...
buddy208 Posted October 28, 2009 Share Posted October 28, 2009 i did the same swap, and you will need to take the cherokee engine mounts, customize the fuel pump on the mj sending unit, all the wiring, and customize the tail lights wiring. fun project took me about 6 months to finish it but totally worth it. Link to comment Share on other sites More sharing options...
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