Eagle

I agree with Hornbrod. Why do you need a write-up to NOT remove something?

I plan on doing exactly that. I think if I use the wiring diagram from the XJ (Cherokee, not Wagoneer), it should work.

Yes. And how about the new Mustangs (actually, for the past several years), with the three-segment, progressive turn signals? Same idea -- it's a batter attention grabber.

It's well known that a flashing or blinking light attracts attention better than a light that's just on. Considering that by the time the MJ came out most cars and trucks world-wide used separate, amber lights for turn signals and hazards, and that the Cherokee had them since 1984, the fact that the MJ does not have them is baffling, inexplicable, and IMHO stupid. If you spend any time on or around construction sites, which I do for a living, you might have noticed that now the rooftop flashers don't just blink on and off, each blink is actually a series of three very quick blinks, separated by a pause, and then another series of three. That gets a lot more attention than a simple on-off-on pattern.

A limited slip differential is a light to medium duty "locking" differential that's suitable for regular driving on pavement because the "locking" is accomplished with clutches that can release. When a vehicle turns, the outer wheel on an axle travels farther than the inner wheel, so the two wheels aren't rotating at the same speed. With a true locker, in tight turns this results in tires chirping and often some clanging and banging from the differential as the diff locks and unlocks. With a limited slip, on dry pavement the tires have enough traction that the torque causes the clutches to slip, eliminating tire chirp, and there is no banging. If you have it, there would have been a tag on the rear diff, but by now that might have been lost. Jack up one rear wheel and try to turn it (with the brake off and the transmission in neutral). If you can't turn it, you probably have a limited slip. However, you could still have a worn-out limited slip even if you can turn it -- the only way to know for sure is to open up the differential and look. The limited slip carrier looks very different from the open carrier. Locking diffs and locking hubs are completely different. If you put a locking diff on the front axle, it creates very unpleasant driving characteristics on pavement. To alleviate this, hubs that can unlock the wheels from the axles are used. When unlocked, the wheels are free to turn independent of the axles, so the locked differential doesn't affect road manners.

No. The locking is in the transfer case, not the differentials. With the 242 SelecTrac option, the "Part-time 4WD" position locks the transfer case so the front and rear driveshafts always turn at the same speed. It seems a bit counter-intuitive at first, but it's called "part-time" because you're only supposed to use it "part time," when the wheels are on slippery stuff. If you run in that position on dray pavement, the drive train will bind up and something will break. In the "full-time 4WD" position, the transfer case engages a differential that allows the front and rear driveshafts to spin at different speeds -- such as when going around corners. This means you can use it in 4WD even on dry pavement. You may (or may not) have a limited slip differential in the rear. If you do, it may or may not be worn out. Jeep never offered a locking front differential in the XJ or MJ. You can certainly install a locker or a limited slip in either the front or rear axle -- or both, if that's what floats your boat. "Lockers" refers to the differentials, not to the hubs. You can have locking hubs with or without locking differentials, and you can have locking differentials with or without locking hubs.

Offset ball joints don't affect toe-in or axle centering. and would not help the problem described in the opening post. Adjustable control arms also won't help this problem. Does anyone know what the backspacing is on the ravine wheels? I don't, but if they are 8-inch wheels I'll take a guess that they have 5-1/2" backspacing and that the extra quarter of an inch is what's making the difference. So either adjust the steering stop bolt, or run quarter inch spacers. (Or even 1/8" spacers might do it.) [Edit to add] MJ factory 15x7 rims are 5-1/4" backspacing. I've found three different Jeep-oriented sites that all agree the Ravines have 5-1/2" backspacing and that with large tires they can cause rubbing. So the cause of the problem here is simply the wheels, and the most direct solution is just to adjust the steering stop.

If you're able to drive it on the street, I'd suggest taking it to an alignment shop and paying them just to put it on the machine and give you a reading of how far (in degrees) the wheels turn in each direction. My best guess is that it's not going to be equal. If the track bar isn't adjustable, it's virtually certain that the axle isn't centered but I'm having trouble visuaslizing how that could affect the tire/rim rubbing on the sway bar bracket. I think I'd consider just adjusting the stop until it doesn't rub.

This may help -- or may not. ALL XJ Cherokees were set up with separate brake lights (red) and turn signal/hazards (amber). That held true from 1984 right through to the end, in 2001. However, the XJ Wagoneers had all red tailights, and the brakes, turn signals, and hazards all shared the same bulbs -- just like the Comanche. The problem people encounter in splicing a Chrrokee front harness to the rear chassis harness of a Comanche is getting the rear lights to work properly -- exactly what you're encountering. I think the answer is to be found in the '88 electrical manuals. Hornbrod gave you the link to the MJ manual. Find the schematic in there for the MJ taillight wiring. Somewhere on the Internet, the '88 XJ electrical manual is also available on-line. Find that -- there should be two taillight diagrams, one for the XJ Cherokee and one for the XJ Wagoneer. They are different. Study where they are different, compare to the MJ diagram, and you should be able to solve the problem.

When Hornbrod posted the link to the '88 electrical manual, you were trying to figure out where the three wires from under the dash meet up to feed the bulbs. Then you apparently gave up on that and tried an aftermarket converter. How much of the late-model Cherokee harness did the previous owner splice in? Was it just the engine harness, or did he also include the dash harness? And do you know what year Cherokee the "new" harness came from?

I don't recall for certain but I believe the MJs sold in Europe and South America has amber turn signal lenses. If that could be verified, reproducing those would be more a matter of upgrading to export specification. But you would still have to modify the wiring harness to get the turn signals to operate independently from the brake lights. MJs are wired so that if you step on the brakes while the hazard flashers are running, the flashers stop blinking. That always struck me as incredibly stupid. XJs don't operate that way (except the XJ Wagoneers).

Niacin (or niacinamide) can also help keep you alert. but don't push it. With anything, when you push beyond your body's natural limits your reflexes, your reactions, and your judgment all go south in a hurry.

I wasn't going to jump back into this, but now I have to. Here's the deal: You may not agree with all the suggestions people here provided, but YOU came here asking for help. Your vast experience with Jeeps is so awesome that after messing with Jeeps for a "looooong time" you didn't know the difference between "cranking" and "firing." Do you really expect us to be impressed? We are all here to try to help each other, but each of us brings to the table the fruits of our own particular experience and the lessons we have learned from the mistakes we have each made over the years. Your friend got lucky with the second ECU. It might not have worked. The fact that he got lucky is not a valid reason to start throwing insults at people who responded to your plea for help with suggestions offered in good faith. But you keep on however you see fit. Just remember, Grasshopper, that the next time you need help, the people you've been throwing insults at are likely to just click past your problem and move on to help someone who appreciates their efforts.

The 8.25 is centered, the Ford 8.8 is offset.

The problem is that what you're looking for would not be a reproduction, because that's not the way the MJs were made. (At least not in the U.S.)

Agreed. Also not worth $64.90, or even $6.49

Most (but not all) 4-cylinder XJs and MJs (especially those with 5-speeds) came with 4.10 gears. [4-cylinders with 4-speeds generally had 3.54 gears, and some early 4-cylinder automatics had 4.56 gearing.] The front axles usually have a tag on the outside showing the gear ratio.

The solution is probably to rip out that entire rat's nest of wiring and start over from a clean slate. The Mopar Performance Catalog used to sell a complete fuel injection conversion for the carbureted YJs. It was basically the engine harness, fuel injection, and ECU from a 95 Wrangler, packaged as a stand-alone system. Something like that is what your friend needs. He already has the manifolds, the injection, and the throttle body. He needs the harness and the computer. (And maybe the fuel pump.) Time to hit the junkyards. http://www.fourwheeler.com/how-to/129-0309-efi-fuel-injection-258ci-jeep/

Ugly.

Only once? I should be buying those resistor packs by the case. And, yes -- when the little rascals build their nest in there, it does create smoke and a burning smell. For awhile -- then the thermal fuse pops, and you have a single-speed fan -- it's either off, or high speed, nothing in between.

The 8.8 also requires an adapter for the rear u-joint on the drive shaft. The KJ axle is a much easier, more straightforward swap.

You could install a Comanche Dana 35, but you would have to relocate the spring perches. Or you could install a Cherokee Dana 35 -- and you would still have to relocate the spring perches. But a Dana 35 is not a good axle. The only reason for using one would be if it's for an MJ, you want to revert to the original SUA setup ... and someone gives you the axle. Bottom line: if you want to stay with spring-over-axle, there is no axle you can use that won't require welding spring perches in the correct location. For the $100 that D35 would cost you, you could probably find an un-welded 8.25 differential and just install that in the axle you have. Just be sure to measure the diameter of your axle shafts, to see if you have an early or late 8.25.

How do you install either a KJ axle or an 8.8 axle in an MJ without welding?

He wouldn't need the computer to adjust for spark. The distributor does it. What was arguably the first automobile dates all the way to 1808. The first vehicles that were more or less practical came along in 1870. That means we managed to have internal combustion engines driving cars for more than 100 years before some genius decided it was a good idea to use computers to control them. We have a member here who is running his MJ with a distributor from a Jeep 4.2L engine. It can be done. The question is whether the computer will handle the injectors without a signal from the immobilizer circuit.

Your opening post said it doesn't crank. Turning over is cranking. So apparently your problem is that is DOES crank, but it doesn't fire. If the problem is the security system, I don't think the new ECM will solve the problem, since the problem originates in the BCM, but please keep us posted with results. If it were mine, I'd go back to the CJ electronic ignition and start driving.