Eagle

You don't need the YJ gauges. I don't think a YJ cluster will fit the MJ dashboard. Find a gauge cluster from an '84 to '90 Cherokee. Best years are '88 thru '90 because the tachometer in those years could be adjusted for 4-cylinder or 6-cylinder. If you get an earlier cluster, make certain that it's from a 6-cylinder. The early ones will also require a different speedometer cable. You can't just plug the YJ gauges into your existing cluster. The clusters use printed circuits, and there's no way to convert an idiot light cluster to gauges. Just buy an XJ cluster and install it.

Donor can be '87-90. 1991 was when Chrysler introduced the HO. Those have a totally different electrical system. Different ECU, different injection, different ignition. Assuming the XJ is complete and undamaged, you can open the hood on that and use it as a road map to check what's been messed with in the MJ.

Yes. In fact, the factory issued a TSB (Technical Service Bulletin) recommending exactly that.

The sensors for oil pressure and coolant temperature are not part of the engine control harness.

You didn't ask. You started off insisting that you need an HO cluster, and that you need an XJ HO under=dash harness. Did the YJ have gauges? If so, the engine already has the correct sensors for the gauges.

1. Is the MJ harness melted? If so, the XJ harness should be pretty much the same, so you should be able to use all or most of it to replace the damaged parts in the MJ. The biggest difference is that the '88 has the C101 connector -- high on the firewall, on the driver's side in the engine bay. That's where the engine side mates with the under-dash part. The C101 connector was troublesome, and for the 1989 model year they eliminated it. 2. Unless you plan to run huge tires, there's nothing wrong with the D30 axle in the XJ. Just engage the disconnector and lock it in place -- there are several articles here explaining how to do that. There's no reason for you to buy another axle if you already have one. Just be certain the ratios match. 3. You'll learn a lot. We're here to help when you have questions.

YOU DO NOT NEED AN H.O. DASH HARNESS! How many times do we have to tell you this? Your existing harness has a connector for the temperature sender in the back corner of head. That's what feeds the temperature gauge on the dashboard. The temp sender in the thermostst housing feeds the ECU. Your existing harness has a connector for the oil pressure sensor. Your '92 engine has an oil pressure sensor. Put the wire on the sensor and you get an oil pressure reading. Use a gauge cluster from a 1990 or older Cherokee. If you use a cluster from a 1991 or newer XJ, the gas gauge will read backwards.

Possibly -- but it was the JL axles that created the aftermarket industry for tube sleeves and 'C' gussets.

My ex-wife and I had a dryer that started making noise. I bought a new bearing unit (that the drum rolls on) and installed it. Not wanting to do it again, I made certain to lubricate the new bearing unit. I used (and still use) Never Seez on all nuts and bolts when working on a vehicle, so I figured Never Seez was the miracle lube, and I used that. The new bearing unit ate itself within two weeks. Next time around I used what I should have used: moly chassis grease. Anti-seize has flakes of metal (usually aluminum, sometimes copper if you buy the high-priced spread) in it, and they are abrasive. The stuff is not intended to be used on things that move in use, and it should not be used on things that move in use because it's an abrasive.

It may have happened, somewhere, some time, but I'm 75 years old and I have never heard of it happening so it's not exactly commonplace. And it is optional, not mandatory.

You can get a gauge cluster with full gauges and a tachometer from a 1984 through 1990 Cherokee and it's plug-and-play with the MJ chassis harness. Your '92 engine should still have a temperature sender on the back corner of the head -- that feeds the temp gauge. The oil pressure sender is a no brainer. And the fuel gauge in a Renix cluster will read correctly, whereas if you pop in an HO cluster the gauge will read full when the tank is empty, and it will read empty when the tank is full. Plus -- an HO cluster has an electronic speedometer, so then you have to deal with wiring that up. The engine harness doesn't enter the cab with an HO system. The ECU is under the hood. You're making a simple job much more complicated than it needs to be.

Okay, but ... You do understand that "may" is optional, right? The home country "may" prosecute does not mean they will prosecute, nor does it obligate them to prosecute. Have you ever heard of even one instance where that happened?

Plug what together? Do you understand what "stand-alone" means? You do NOT need to connect the YJ engine harness to anything at the firewall (what you call the "bulkhead"). The '92 computer mounts on the inside of the driver's side fender, under the hood. Why would you want to get an HO dash harness for a Renix vehicle? If you do that, your fuel gauge will read backwards. Leave the dash harness alone. "If it ain't broke ... don't fix it."

Don't use anti-seize! It is NOT a lubricant. And, yes, there is a story that explains how I learned that rather painful lesson -- and it was a lot more expensive than a speedometer cable.

He's looking for a 2.5L aluminum valve cover.

No, I'm suggesting exactly the opposite. I'm suggesting using the '92 YJ engine harness to run the engine, and leaving everything else alone. If Chrysler can separate out the HO engine harness and sell it as an aftermarket upgrade for the 4.2L, there's no reason why you can't use it as a stand-alone. I just don't understand why you seem to be fixated on messing with wiring that isn't part of the engine harness. "If it ain't broke ... don't fix it."

I have never heard that.

They are on the engine side of the firewall, but they are not part of the engine harness. I don't understand why you need to "wire them in," since they are already wired in and ready to go. You have a '90, so it originally had the ECU computer under the dashboard, but it did not have the C101 connector on the upper firewall (engine side). The new ECU should be mounted in the engine compartment, hopefully on the inside of the driver's side fender where it would be on a '91 or '92 MJ. So you'll have some wires going through the firewall that will be abandoned (or you can remove them to reduce clutter and confusion).

So get the wiring diagrams for both and adapt. To reiterate: Jeep sold the '94 4.0L Injection/ignition setup as a stand-alone conversion for the older 4.2L Wranglers. That means the engine harness can be used completely independent from anything else in the chassis harness, so IMHO it doesn't make any sense to change things that don't need to be changed.

I still don't understand why there's a need to change anything besides the actual engine harness.

What year MJ? You can make anything work -- it's a question of how much you want to make it happen. For what it's worth, the Mopar Performance Catalog used to sell the '94 Wrangler injection/ignition system as a stand-alone package. It was intended for upgrading the early, carbureted YJs to fuel injection but, since it was stand-alone, that tells us that you should be able to run the engine harness from a '92 YJ as a stand-alone, and not have to mess with the chassis and under-dash harness of the MJ.

Do you really want as much backspacing as possible, or do you want as little as possible?

The header will fit, BUT you will need corresponding grille and headlight bezels.

If your MJ has a manual transmission, the clutch master cylinder may have leaked hydraulic fluid onto the fuse panel. That corrodes and destroys the contacts. You may need to source a replacement fuse panel from a wreck with an automatic.

What are you trying to call out? I see at least two butt splices in that photo that definitely didn't come from the factory.