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Swapping an OBDI HO 4.0 L engine into a Renix 4.0 L system. Both engines starting out mounted to Automatic Transmissions. (I used a 93 sport & 89 Pioneer) Parts used from OBDI system: Engine & intake/throttle body Fuel Rail Accellerator Cable (going to gas pedal) Transmission kickdown cable (must be removed/installed inside transmission by dropping pan) Exhaust system IAC sensor Air Box & hoses Power steering pump & bracket (I believe either can be used, but I used this one) Open cooling system radiator & window washer fluid bottle (reused as overflow bottle) Parts used from Renix system: Computer & wiring harness All Sensors besides IAC on intake Flywheel & CPS sensor Alternator Starter Distributor Coil Vacuum lines EGR will be deleted (but can be left plugged in) Air Conditioner AC & Alternator brackets Parts you will need to purchase: Fuel line extensions & clamps Vacuum lines to replace worn lines (not required) Possibly wiring & electrical tape to extend/adapt lines Transmission fluid ~4qts Power steering fluid ~1qt The Swap Process: I basically followed this website's overview: http://www.off-road.com/jeep/cherokee/9 ... gswap.html Here is another link some have found helpful, but I did not refernce this link myself when doing my swap: http://www.rockmodified.com/offroad/Tech/TB/tb_perf.htm But I think that adding my description of my swap below will help others with questions some more. I started the swap with 2 "complete" vehicles, which is the easiest way to do the swap in my opinion. If you do not have the vehicles, and just have an engine from a junkyard, make sure you also purchase the items listed above which may not come with the engine. I pulled the engine from the renix system first, taking care to note where vacuum & electrical lines hooked up to which sensors. I ended up pulling the transmission with the engine due to my inability to access a few bellhousing bolts. (Pulling the tranny involves removing the shifter, driveshafts, crossmember, t-case linkage , exhaust & possibly a few other small things) I believe it is actually easier to do it this way due to the ability to access a few parts for removal/installation and to mount the engine to the tranny. I then removed/replaced the tranny kickdown cable and removed the CPS/flywheel from the old engine. I have found it also makes it much easier to remove the engine/tranny combo and access the engine during this swap if you remove the nosepieces, radiator and grill. I did not have working AC in either vehicle and had no desire to, so I just cut the condensor lines (systems were previously drained. Now I removed the newer engine & tranny in the same method and removed the tranny kickdown cable. I also removed the exhaust system to reuse in the other XJ since the downpipe will be used from this system. Now, with both engines out and side-by-side you will need to compare sensors, electronics & the pully system. Now is also a good time to change from/rear main seals if they are leaky. First, I mounted the Renix flywheel in place of the OBDI flywheel. Next you will need to pull all of the sensors out of the old renix block and mount them to your new OBDI block, they should all have places to mount in very similar locations to where they were before. Most will mount in exactly the same spots, but I believe the knock sensor has a lug in the block that has to be removed to insert it in the block. After this, you will need to change over the AC/Alternator brackets and the respective components. *I have heard that if you use a HO Jeep Wrangler engine that the water pump must also be swapped over as the flow routes differently. Now, I mounted the engine to the tranny and bolted up the flywheel to the torque converter. Easiest XJ CPS mounting job ever! Drop the new combo into the engine bay and hook up all of the vacuum lines and electrical lines you can. There will be a few pieces that you have to fabricate: --- The newer fuel rail has both ports at the front; whereas the Renix system originally has one at the front and one at the rear. You will need to cut/flare/splice longer fuel line between the lines on the frame and fuel rail. --- The TPS for an Automatic Tranny will need to be modified to work with the HO throttle body. Both are currently male pieces and one needs to become a female for them to work together. I also think this link may be helpful for DIY: http://naxja.org/forum/showthread.php?t=905450 If you want to spend a few dollars this is really nice: http://www.hesco.us/shop.asp?action=details&inventoryID=45563&catId=7972 --- I extended the old radiator temp sensor wire & mounted it into the hole in the thermostat housing. My electric fan never worked before the swap on its own, so I don't know if this helps or not. I have a toggle switch for the fan in the cab if my temps go up to 210. --- The old closed cooling system routes differently than the open system & the open system needs an overflow bottle. I reused the newer windshield washer fluid in place of the stock closed cooling system bottle. I removed the bottle & mounting bracket & mounted the new bottle right there on the firewall. You won't be able to use the HO's overflow bottle, as it mounts to the same location as your Renix coil is still mounted at. --- That's all I can think of, if you run across a problem, send me a PM. Here is a finished shot: Don't forget to swap your badges to confuse everyone!

Did you check the axle's u-joints? If one of those blew it would cause similar problems with binding.

I don't see how it could be much more complicated than swapping a OBD1 HO into a Renix electrical system. Just put the block & intake/exhaust in there and put EVERYTHING Renix on the new block, the only thing I am not 100% sure of switching from is the 2000+ don't have a distributor & spark plugs; can you put spark plugs in those holes? Yes, your aw4 will bolt right up but the newer intake requires you to use the newer kickdown on your "old" AW4. Here is an old write-up of a swap I did. http://www.terrainstompers.com/forum/viewtopic.php?t=14

I am very happy with my Rough Country lift kit on my XJ & they have excellent customer service too. Check out their 6.5" lift: http://roughcountry.com/Jeep_MJ_6in.htm Call Jason at 800-222-7023 ext 121 - he'll get ya set up!

An 87 MJ should have a 4.0L & AW4 transmission if it is automatic, if it is standard then it has the BA10 Peugot tranny (& you'll need a custom pilot bushing if it's a 5-speed to mate it to a HO motor). This may be of some help to answer your original question: http://www.terrainstompers.com/forum/viewtopic.php?t=14 :cheers:

I would suggest keeping an eye in your local "Trading Post" and Craigslist.org. Wait for a a wrecked XJ to come up on there or one someone is parting out. You can drop in any 4.0L 86-90 w/o changing anything at all. You can drop in a 91-97 engine with minor modifications to your Renix electrical system (NO harness swap necessary as posted above). The best way to do this is to find a wrecked or rolled XJ or ZJ as you'll need a little bit more than just the block to swap in a newer HO 4.0L. I have a write-up here that many have found very useful. http://www.terrainstompers.com/forum/viewtopic.php?t=14 When I dropped in my 93 HO motor I left the larger injectors in it for more power; but it sucked more gas that way. If the donor's radiator is in good shape you convert to an open-cooling-system too!

I think the front looks odd cause of the cut-down factory bumper. Get/make a bumper that wraps down under the corner lights & it'll look 100% better.

Sorry, I hadn't read the part about you already pulling the pump! Just hook it back up to the in-tank assembly & slide it back in the tank hole, then you can test the pressure at the rail. You don't want to mess with sparks around an open gas tank! :eek: :eek: :eek:

You can buy a cheap fuel presure guage at Autozone or whatever & hook it onto the fuel rail to test the pressure. I cannot recall the correct starting pressure, but it may be 35psi?; it should be easy to find in a search though.

Yes, seriously.

Get a MAC.

I bought a starter relay for $8 at Autozone for my 89 XJ, the relay for your MJ should be the same... just take yours when you go cause they don't list them correctly & you need to physically compare to be sure you got the right one.

I've done this 3 times now on XJs, but I would assume a MJ would be darn near the same thing. It takes at least 2 days (depending on help). Basically you just unbolt the 2wd & bolt in the 4wd, but it's the little stuff that adds up. (stuck/broke bolts, lines, cables, etc.) (last time took me around 20 hrs total including trips to parts stores & tool stores replacing broken tools, also including lifting the rear of the Jeep at the same time) (+ another 4-6 hrs to pull the parts from a donor too) Get a matching front for your rear end, or get a set of 4.10 axles (regearing is good!) and a 4wd tranny/tcase & driveshafts. Be sure to get the tranny tunnel linkage & handle for the tcase. Everything bolts right in, but I would suggest that if you're gonna have the front axle off, you might as well drop in a lift at the same time. I recently purchased a Rough Country 4.5" lift for my XJ, I believe their MJ kit is a great price as well.

Yes, I've had this happen a couple times too, those sides are real sharp to line up 6 injectors at the same time. Get another set of o-rings & try again, I think it took 3 tries for me (after the 2 or 3 tries with discovering other bad injectors that still leaked...) to get them all seated w/o any leaks.

I've replaced a couple 4.0L motors in a weekend, they're pretty simple to pull & replace yourself in a garage. Hopefully someone local to you (or the truck) will come forward to do the swap. You can usually get a wrecked XJ with a good 4.0L for cheap.