Eagle

The FSM for my '88 4.0L Cherokee specifically says not to turn the flywheel.

Maybe it turns on the anti-lock feature? You are aware that the Rodeo uses 6-bolt hubs, right?

BTW, I believe 1990 was the year they changed the grille and header, so if your grille is good and all you need is the header, 1984 thru 1989 XJ will be the years that fit. 1990 and newer you would need the header plus a new grille and both headlight bezels.

Received Carfax. Thanks to 1987Comanche

If anyone has a Carfax account (or access to someone who has one), I would very much appreciate getting a report on this 2001 Cherokee I just bought. I screwed up, and allowed myself to be blinded by the fact that it was a Cherokee Sport with under 100,000 miles, and the body looked pretty decent. So I bought it without checking it out as closely as I should have. Now that I have it ... I can't drive it. No brakes, and the cause is that just about every hard line under the floor is rusted out. There's rust on the bottoms of the doors on the driver's side, and even the driver's seat frame is rusty. I'm beginning to think it may have been in a flood. Too late to undo the deal, I did buy it "as is." But I'd like to try to get a handle on what I've got and what I can expect for other problems. It supposedly went through a Jeep dealer at the east end of the state, so it may have found its way into Carfax -- I hope. VIN is 1J4FF48S61L553249 If you can run the report and save it or scan it as a .PDF, hit me with a PM and I'll provide my e-mail address. Many thanks

Here's the official FSM procedure to follow when bleeding the brakes on an MJ that still has the two lines to the rear:

No, that sliding piece does NOT distribute which way the fluid goes. Look at that photo, at the "nose" of the metering block. The front (left) top is the fluid inlet for the rear brake circuit. Notice that it connects directly to the nose outlet, which is the line that goes to the rear. What controls how much brake force actually gets to the rear wheels is the rear height-sensing proportioning valve. And because the MJ has that rear proportioning valve, there is also a second, bypass line from the front to the rear. There is a very specific bleeding procedure that must be followed when doing the MJ brakes in order to get that bypass line bled. Since you didn't even know where your proportioning valve is, I suspect you were not aware that this procedure is necessary. Detailed instructions have been posted here a couple of times in the past.

The slider on the top? That's what turns on the brake system warning light in the event of a loss of brake pressure. It is reset to the center position after bleeding the brakes by stomping on the brake peddle -- HARD! It cannot cause a complete loss of rear brakes. Here's a photo of it, cut in half. The rear brakes are fed through the horizontal port on the left of the photo (the end that faces the front as installed in the truck).

Before you fire up the welder, take however much time you need to figure out just how that strike works. It is NOT fixed in place. There's a weld nut on a backer plate of some sort, and the strike itself is basically a threaded stud that screws into the weld nut. It HAS to be that way, so the strike can be adjusted. I would suggest that you remove the trim panels on BOTH sides, so you can inspect the good side to see how it all goes together.

And now that the heat of summer is approaching, it's time for me to install one of those conversion kits such as I showed the image of. I have never worked on an automotive a/c. I know that with the R134a systems the low pressure side gets a small port connector and the high pressure side gets the large port connector. For an '88 XJ or MJ with the factory system, which is the high side and which is the low side?

There is no pin inside. Are you asking about the "thingie" up front, next to/beneath the master cylinder? That's the proportioning valve on an XJ, but not on an MJ. On the MJ the proportioning valve is in the rar, and it changes the brake bias depending on how much weight is in the bed.

You are better off looking for 4-door XJs. First, they are easier to find. Second, the Comanche uses the same doors as the 4-door XJ, not the 2-door.

This is NOT a good idea. Those steel front lines are now 20+ years old and have most likely been exposed to a variety of environmental conditions. They are brittle, and they may crack if you start bending them.\ Use the front hoses from a mid-90s YJ Wrangler.

You're there. According to the factory service manual (FSM), at 90 degrees ambient temperature, the output at the dash center vent should be 37 to 48 degrees F. At 100 degrees ambient, the output should be 43 to 55 degrees F. He's an A/C guy and he's never seen a system that cycles? I'm a car guy and I've never seen one that doesn't. It has to or it won't work. Back in the late 60s to early 70s, AMC cars (and I think GM as well, don't know much about Fords) had an adjustable cycle on the compressor. The max was a setting called "Desert." It was called that because it could only be used in hot, dry conditions, with virtually no humidity. Where I lived we had humidity. If we turned that dial all the way up to "Desert," we'd see fog blowing out the dash vents ... for about 5 minutes, right up until the evaperator froze up with a solid coating of ice on it. We have an '88 XJ, an '87 MJ, and '88 MJ, and two 2000 XJs and one 2001 XJ with A/C. They all cycle, even on MAX.

I have a 2.5L that came out of a '94 (approximately) Wrangler, so it's set up for a Mopar injection rather than Renix. It was given to me and I have no use for it. If you want it, it's yours for the shipping. I can probably scrounge a pallet somewhere. I don't know if it runs or not, but I do know it was removed to make space for a Chevy V8 conversion, so I believe it was running when pulled. IIRC it has a Chrysler 3-speed auto tranny bolted to it -- you can have that, too, or save the weight if you don't need it.

What diameter are the ring gears? Looking at the part numbers you listed, they all include "41 10" in them. My guess is the ring gears have 41 teeth, and the pinions have 10. 41 divided by 10 is (drum roll, please) ... 4.10. I'll take a wild guess that you have front and rear gears for 4.10 ratio.

Cap+rotor+plug wires.

Up through at least 1969 the AMC engines still used conventional points and condenser and a conventional ignition coil for spark. Somewhere in the early to mid-1970s they changed over to a transistorized distributor (no more points and condenser), but the coil remained essentially the same as it had been for decades previous. This HEI (High Energy Ignition) distributor is basically nothing more than a modern version of the transistorized distributor from the 70s. Unless you are replacing an older points-and-condenser distributor, it doesn't really do squat for you. It's best used in conjunction with a high-energy ignition coil. But ... the coil in the Renix and Mopar XJ/MJ systems is already a high-output coil, and the distributor is already a breakerless (no points or condenser) distributor, so there's no gain. Beyond that, as jimoshel mentioned, in the MJ systems (both the Renix and Mopar) the timing is controlled by the ECU based on a variety of inputs, to optimize spark timing to operation. With an old-school (comparatively) HEI distributor, the ECU can't talk to it so you're back to controlling the spark timing just be engine RPM and perhaps engine vacuum (if it has a vacuum advance port). That's why I commented three years ago when this thread was fresh that the HEI distributor is going backwards in technology. Compared to the stack Renix or Mopar systems, the HEI doesn't gain you anything and very likely loses a lot.

You won't find 3.07 gears in a ZJ, unless you find one of the EXTREMELY rare 1993s with a 5-speed. That was the only year Jeep offered a manual transmission in the ZJ. All others are automatic and will have either 3.54s or 3.73s. I thought this was unusual. http://inlandempire.craigslist.org/cto/3020282650.html It's also not a rust bucket, which is also rare for the 93s. Being the first year for the ZJ body, there were some problem areas that were very prone to rust-through. I'm sure being a California vehicle doesn't hurt.

What year? Internal or external slave?

Looks like you have to make a decision. There's only one cab type for the MJ -- standard. No crew cabs, and no extra cabs. Once you accept that as reality (if you do), the MJ is the front part of a Cherokee with a pickup box on the back. But you're right -- it is old. 1992 was the last year they were made, so the NEWEST Comanche you can possibly find today will be 20 years old. But Jeep hasn't offered any other pickups since then, so if you want a Jeep and you want a Pickup, the MJ is almost the only game in town. J20s are extremely rare, and much older even than MJs.

The stock exhaust for the 4.0L is 2-1/2 inches from the manifold to the catalytic converter. The cat has a 2-1/2" inlet and outlet, and the connector to the muffler necks down to 2-1/4" between them. The muffler and tailpipe are 2-1/4". If you're not going to run the cat (or even if you are), just use a 2-1/2" muffler instead of 2-1/4" and have a tailpipe custom bent. However, I don't think you'll like it. Back in "the day," my brother managed a Speedy muffler shop. The first replacement exhaust for my '88 XJ was a birthday gift from my bro' -- a 2-1/2" turbo muffler and a custom-bent 2-1/2" tailpipe. The sound was marginally "throatier" than a stock muffler, I had noticeably LESS low-end torque, and I lost 2 miles per gallon from my fuel economy. In short -- it sucked. That's the only time in my 68 years on this planet when I was actually looking forward to needing a new exhaust system, so I'd have an excuse to get back to stock parts.

You won't find 3.07 gears in a ZJ, unless you find one of the EXTREMELY rare 1993s with a 5-speed. That was the only year Jeep offered a manual transmission in the ZJ. All others are automatic and will have either 3.54s or 3.73s.

More likely the wire is broken. The sender is a variable resistor, with a range of 0 to 88 ohms. 0 ohms would be a short circuit (zero resistance) and should result in a reading of 0 psi on the gauge. An open circuit is no current flowing (infinite resistance) and should result in the gauge being pegged beyond the 80 psi end. Simple test: turn on the ignition -- the engine can be running or not, it doesn't matter. Remove the wire from the sender and DON'T let the connector touch anything. The gauge should read 80+ psi. Then ground the terminal to a known-good ground on the engine block. The gauge should read zero.

A limited slip is no different than a full locker on ice. There isn't enough tire traction to overcome the clutches in the LSD, so on ice it acts just like it's locked -- because it is. Nevertheless, I want a LSD in any rear-wheel drive street vehicle I own. It's the difference between getting home in a winter storm, or parking at the bottom of some hill in the middle of nowhere.