Eagle

Comanche and Cherokee use the same sensors, but the senders for oil pressure and coolant temperature with idiot lights are simple ON/OFF switches, and the senders for gauges are variable resistors. You can use the senders from the donor vehicle, or you can go to Auto Zone and order the sensors for use with gauges.

DOH! I did actually. Seemed like a good idea at the time haha But I tried grounding the wire to the block, as well as unplugging it and noticed no change in the gauge reading. Well, there's your clue. The sender range is 0 (zero) to 88 ohms. The classic test for a non-functioning gauge is to unplug the wire from the sender. With the ignition on, this creates an open circuit (infinite resistance), which should peg the gauge all the way to the right. Then ground the wire to a known good ground on the engine. This creates a short circuit, or zero resistance. The needle should then peg all the way to the left. If you do this and the gauge doesn't move, either the gauge is faulty (which you can check by removing it and repeating the est using jumper wires) or there's an open or shorted wire between the sender and the gauge cluster.

Is there an OME shock listed for the ZJ? I believe the ZJ rear shocks are longer than the XJ and might be right for an MJ at stock height.

My '88 XJ Pioneer has a tachometer. A lot of them do -- it was a factory option. Yes, the tach should function. The wiring is all there -- it's plug-n-play.

Considering that the MPFI conversion kit Jeep used to sell for the 4.2L carbureted Wranglers was nothing but the engine room harness from a '94 4.0L with MPFI, my guess would be that the dash harness is going to be okay. Why would they make two different dash harnesses for the same vehicle? The tach should have a potentiometer on the back to adjust between 4-cylinder and 6-cylinder.

'88 XJ, 4.0L 5-speed, stock gears and 225/75R15 tires I typically get around 19 in local driving and 20 to 22 highway. '88 MJ, 4.0L 5-speed with 3.73 gears and 31x10.50-15 tires, about 17 in local driving and 19 MPG highway.

The axle itself will bolt right in. Just pop the draglink loose at the pitman arm, pop the track bar, and move everything over. The control arms are the same for all years of the XJ and MJ, so you can either leave them in the vehicles, or move them with the axle. I'm not certain, but I DON'T think the calipers are the same. I think you'll have to use the 2WD calipers on the 2WD axle. Jeep changed the calipers beginning with 1990.

Not true. There's an efficiency point that moves around depending on load and a few other variables. Usually it's significantly below peak torque. Best mpg I've ever had was cruising at around 1800 rpm. If I go much faster, my fuel economy makes a steep downward curve. onlyinajeep726, where did you get that list and what exactly are the numbers? As in where do they come from / how were they determined? For the engine, the torque peak RPM is absolutely the most efficient operating speed. Torque is mundanely defined as "horsepower per revolution." so the engine speed that produces the most power per revolution is the most efficient engine speed. In a vehicle, of course, outside forces come into play. Most importantly, aerodynamic drag and parasitic losses due to friction increase exponentially with vehicle speed, so there is a point where the direct correlation breaks down. I'll get to that in a minute. I have experimented with this mostly with the '88 Cherokee, which is a 4.0L 5-speed. I live in Connecticut, where most of the highways still have 55 MPH speed limits, and a couple of stretches of interstate allow 65. I only use 5th gear on the highway -- 55 MPH in 5th gear is only 1540 RPM, and 65 MPH is only 1820 RPM. Below 55 MPH, 5th gear is totally useless with the 3.07 gears. I have on several occasions driven the same route in 5th gear and then again using only 4th gear, and every time the gas mileage is equal or better using only 4th gear. Using 4th as the cruising gear, 55 MPH is at 2055 RPM and 65 MPH is at 2430 RPM. So in 4th gear, 60 MPH is sitting right on the torque peak, and delivers the best gas mileage. I had another proof of this a number of years earlier. When I was in the Army, I drove a Rambler American, with an earlier version of the engine that became the 4.0L Jeep engine. That car was a 3-speed manual with 3.07 axle gears. The gearing worked out such that 2500 RPM was exactly 60 MPH. Running at that speed, I got 28 MPG -- the dealer asked me to never mention that in front of other customers, because they'd all complain that their Rambler wasn't doing as well. A 6-cylinder Rambler American wasn't exactly a race car, but I wanted to optimize the performance. I pt on a straight-thru glass-pack muffler, tweaked the ignition timing (we could set it, in those days), and made up a home-brewed open air cleaner to replace the fully-enclosed can that was standard from the factory. I took it out on I-95 near Edgewood Arsenal, MD, late at night to test my tweaks. I finally broke 100 MPH -- got it up to (IIRC) an honest 104 MPH, after correcting for speedometer error. Then came Winter. I needed snow tires, and I couldn't afford them. My brother had switched from bias-ply tires to Michelin radials, so he gave me his snow tires. They were from a larger, heavier car and were probably four sizes larger than my tires. But they fit inside the wheelwells, so I used them. One night I took the car back out on I-95 with the snow tires on to check the top speed. It dropped, from 104 to 80. Why? Because the larger tires reduced the effective final drive ratio enough that the drag curve crossed the power curve, and above 80 MPH (which should have been 3333 RPM but dropped well below that with the bigger tires) there just wasn't enough horsepower available to overcome the aerodynamic drag and parasitic losses above that speed.

I would try the Pennszoil Synchromesh transmission fluid. I have heard good reports on how it performs in the Jeep transmissions, even though it wasn't formulated specifically for them.

2250 RPM, for any gear. The most efficient engine speed is the torque peak.

The dealership CAN order them. They are in the Mopar Performance catalog, and I have posted the part number several times in the past. They are by FAR the best deal going. The Mopar part sells for about one-third what anybody else gets, they come as a pair (when you see the price, you'll be sure it's only for one perch), and they are MUCH heavier-duty than the perches on the stock axles. That's because they are made for building heavy-duty axles in race cars that put a lot of torque to the ground. Found it:

NO! If you do this, the steering wheel will be off-center when the steering box is straight, and when the steering wheel is straight the steering box won't be. DO NOT DO THIS -- IT'S WRONG.

You can resurface the 2.5L flywheel, but if you're on a tight budget why do it? Buy a Scothbrite pad, chuck it into your electric drill, and buff away the rust.

What you're overlooking is that in 1988 they offered high RATE (meaning higher capacity) springs that did not increase the ride height. I made the mistake of ordering my 1988 Cherokee with the optional, heavy-duty (not "off-road") suspension. It rides at the stock height -- 17-1/2" front / 17" rear. But it rides like a ... well, like a truck. And after 25 years and 287,000 miles, including hauling some VERY heavy loads, it hasn't sagged even a fraction of an inch. Those are a different animal from the later model XJ "Up Country" springs, which were part of the off-road package and were intended to increase the ride height by an inch compared to the standard suspension.

Actually, factory ZJ V8 springs generally lift an XJ or MJ exactly one inch. But, as you can see from Hornbrod's list, they are not all the same. In fact, at times Jeep would put different number springs on each side to level out the ride height depending on options in the vehicle. I ordered what is now my wife's 2000 XJ Classic from the factory with the Up Country suspension. That rides 1 inch higher than "stock." Before I had the chassis rustproofed, I crawled under and read the codes off the springs, then I ordered a pair for use in my '87 MJ. When I have the spring number to the guru at the parts department, his immediate response was, 'I though you only had XJs and MJs - why are you buying a pair of ZJ coils?" I subsequently picked up a used 2001 XJ without the Up Country suspension. I bought another pair of the Up Country (ZJ V8) coils) and threw them into that. I measured both sides, before and after the installation. They lifted the front exactly one inch.

Be sure you have the correct slave cylinder/throwout bearing. The one for the AX-15 has a larger inside diameter than the one for the AX-5.

Not machining the flywheel was a good thing. The FSM very clearly says not to, and I know people who have ignored that to their detriment.

Using an MJ as a daily driver is incompatible with running 35" tires. Make up your mind.

An alternate diagnosis would be that it IS switching from open loop (warm-up) mode to closed loop mode, and that one or more of the sensors used in closed-loop mode is faulty. Several sensors are by-passed in open-loop mode, so if it runs fine with sensors by-passed then doesn't run well with the sensors are in the loop ... that should tell you where to start looking. I think the oxygen sensor would be a good place to start.

A very long time ago I needed to do a brake job before heading off for a weekend to pick up my then-fiancee in another state and from there trek over some mountains to visit her grandparents. To get it done, my brother came over and, while I did one side he did the other side. Cool, bro, thanks a million. As we started down the back side of the mountains, the brake warning light came on and the peddle dropped. Oh, bleep. Fortunately, the car was a manual transmission with a high compression V8 so there was plenty of compression braking available and we made it fine with only the front (disc) brakes. After I returned home from the weekend, I pulled the rear brakes apart to see what might have gone wrong. What went wrong was that my helpful brother wasn't as careful working on my car as I know he would have been on HIS car. He assembled on of the link bars between the piston and the brake shoe wrong, and it came off under pressure. Once the link was gone, there was nothing holding the pistol in the wheel cylinder, so it popped out. The parts were there and I was able to reassemble the wheel cylinder, but the fluid had ruined the brand new brake shoes on that side. And, of course, they don't sell brake shoes for just one side, so ... That was, IIRC, 1973. In the forty years since, I have never allowed anyone but me to work on my brakes. But I digress. The point of this shaggy dog story is simply that it is possible to put things together wrong, allowing a wheel cylinder to pop. Double check how everything fits together.

How could it pop off? First off, the rubber cap you can see is only a dust cap. The actual gland/seal is inside the cylinder. There are two, one facing front and one facing rear. Then there are two metal (or sometimes plastic or ceramic, I guess, but I'm ancient and I've only seen metal) pistons, then the rubber dust boots. If you have a pre-1990 MJ with Bendix drums, there should be short connectors that extend from the metal pistons to the front and rear shoes. If you have a 1990+ with 9" Chrysler brakes, the shoes contact the pistons directly. http://constructionforklifts.tpub.com/TM-10-3930-621-34/TM-10-3930-621-340128im.jpg With a bleeder screw open, you just can't generate enough pressure to pop anything. Please tell me you weren't bleeding the brakes before you reinstalled the brake drums ...

How do they work? I see gutter clamps, but I don't see any way to attach them to a rack. The angle looks wrong for welding, and if you weld them the measurement for width has to be exactly correct. Doesn't look like a good choice to me.

So if it's leaking from a wheel cylinder ... you replace the wheel cylinder.

Plus the 207 has a low ratio of 2.6x and the 231 is 2.72:1. Slightly better crawl ratio. And better oiling.

I think it will look just fine. I don't think you'll have much luck finding light small enough to fit the corner notches, but I don't thank that will matter at all. I'm interested in what you find for mounts, because I'm planning to make something similar (probably a very short version of a Garvin Wilderness Rack) and my big question is what to use for mounting hardware.