Eagle

It's much easier than going the other way. You can get a shifter from any XJ (Cherokee). Keep in mind that different engine/tranny/transfer case combinations use different length control rods under the floor, so ideally you should get the parts from an XJ that has the same engine, tranny and transfer case as your MJ. The floor pan of your truck is already set up with the mounting points, just bolt the pieces in and go.

Yeah, but the towing instructions are based on the assumption that the front wheels will be off the ground (for a tow truck) or all four wheels will be on the ground (like for flat towing behind an RV). With the transfer case in neutral, aren't the front and rear axles locked, and just not connected to the transmission? I don;t think you *CAN* tow on a dolly with the transfer case in neutral. I don't think they fixed that on the XJ until 1994 or 1995. Better check before you rent the dolly. I would pull the rear driveshaft and cap the tail of the transfer case with a cut of soda bottle and hose clamp.

Has the speedometer been recalibrated for the larger tires? Did you re-gear when you put in the lift and big tires? Frankly, 15 MPG with 32" tires and a 5" lift is probably about as good as you have any right to expect.

A bored-out throttle body might help with performance, but it won't help with gas mileage. If anything, it'll make it worse. Read this thread: http://comancheclub.com/forums/viewtopic.php?t=9328 It starts off about exhaust pipe size, but it gets into the differences between the original 4.0L engine (which you have) and the HO. Too many owners of the non-HO version think they can make some magic, $5 tweak that will transform their engine into an HO version. Not gonna happen. The original 4.0L engine was not designed to run at high RPM, and was not designed to be a street drag champion. If your definition of "performance" is drag strip acceleration, you have the wrong vehicle and the wrong year. But ... 15 MPG is worse than your gas mileage should be. Is the truck all stock? 5-speed or automatic? What tire size? Does it have the stock gearing? Is that around-town mileage or highway mileage? How do you use it, and are you heavy on the throttle or easy on the throttle?

Running with a net instead of a solid tailgate helps, or a cap or a full bed cover

It should be an AX-5. It sounds like you may have a failing slave or master cylinder. First step would be to try bleeding the clutch hydraulic system.

Yes, but why would you want to? The original shift knobs for the BA 10/5 years are rubber, with a ceramic insert around a steel insert. The ceramic breaks, the rubber pulls off, and then you have to buy a whole new knob because there's no good way to repair them. (Believe me, I have tried.) I've swapped all mine over to the new style. Do it once and it's done.

If you're on stock tires that means you are cruising at 75 MPH. If you're on larger tires, it's even faster. 3.07 gear will NOT help your gas mileage, and may make it worse. The problem is you're driving a brick on wheels, and aerodynamic drag increases exponentially with speed. Back when I briefly owned a 99 WJ 4.7L, which had a more slippery shape than an MJ, I found that the gas mileage increased about 3+ MPG if I dropped the cruising speed from 70 to 60. I suspect the difference will be greater with an MJ. At 2300 RPM you're in the "fat" part of the torque curve. You won't gain much gas mileage by gearing to run well below the torque peak. That worked for AMC to beat the government economy tests, but those were run on a dyno, with no aerodynamic drag to factor in. That's why those mileage figures were pretty much invalid except as a comparison between different vehicles. They were useless as far as predicting what mileage you'd get in real world driving.

The tach wiring is all in place -- it's straight plug-n-play. You just have to be sure to get the right cluster for your year. You canNOT just add a tach to your cluster. The printed circuit on the back is different. You will need the complete cluster, even though you already have the other gauges. What it means, though, is that you would not need to replace your temperature and oil pressure senders.

4.88 3.73 with 31s is equivalent to stock 4.10 with 33s is barely better than stock IMHO, I view decent "all purpose" ratios to be 4.10s for 31" tires, 4.56 for 32" and 33" tires, and 4.88 for anything larger than 33" tires. The only reason I stop at 4.88 is that's the deepest ratio available for a Dana 30 front axle.

For the tranny shifter, they are all the same -- doesn't matter if it's a BA 10/5, an AX-5 or an AX-15. It's metric, I remember that for sure, and I also remember that my parts guru at the dealership had a helluva time figuring out what it was. It's too small to be 12mm (that's almost 1/2", so I'm going to guess it has to be either 10mm or 8mm but I don't have a clue what thread pitch.

Railroad ... railroad ... I've heard that word before. Wait, it's coming back. Trains used to run on "railroads," right? I think I can remember riding on a "train" when I was a kid. Do we still have trains and railroads in the U.S.? I thought the tree huggers converted all the railways to bike trails years ago.

Because it's a crappy carburetor? That would be my first guess.

No, the multi-port version of the 2.5L produced quite a bit more horsepower and torque than the TBI version. It's a conversion that is VERY worthwhile doing. Jeep's price on essentially the same conversion for the old 4.2L Wrangler I-6 was something like $1500 or $2000, IIRC. For a 4-cylinder and used parts, IMHO it has to be worth at least $500, maybe a bit more.

My '88 MJ had stock 3.07s when I bought it. I *HATED* it with 31s.

Gear ratio alone isn't the entire picture. Tire size enters in. As I've posted before, my '88 MJ got the 3.73 gears I originally bought for the XJ, and for the XJ I was going to run those gears with stock 225/75R15 tires. The MJ ended up running those gears with 31x10.50s. In terms of speed to RPM, the actual final drive ratio was exactly the same as my wife's XJ with automatic and 3.54 gears on stock tires. And set up like that, the MJ got 19 to 21 MPG on the highway, with the tailgate up. I'm now driving the MJ on stock 215/75R15 tires. It's a great ratio for street driving, but the speedo and odometer aren't accurate now so I haven't calculated the gas mileage with this setup.

Sorry ... I tend to get carried away on occasion. As a friend says (about himself) on another forum, "Why write a quick note when you can write a novel?"

Okay, how about this little thingie? http://www.msdignition.com/pdf/7563_frm27132.pdf You'd want it to run 5 seconds after start, right? So maybe it gets wired in with the second oil pressure switch somehow? Or maybe just set it for 8 seconds and hope the engine starts in the first 3 seconds.

Another thing you younger folks don't take into account, because you weren't driving and paying for gas when it was a problem, is that AMC was oriented toward gas mileage. Especially in the days of gasoline shortages and being able to buy gas only on odd-numbered or even-numbered days, to match your license plate number. Both my 1966 Rambler American (I-6, 28 MPG highway) and my 1968 Javelin (343 V8, 24 MPG highway with an honest top speed of 147 MPH) were geared at 24 MPH/1000 RPM. That meant 60 MPH was eactly 2500 RPM, and 3,000 RPM took you 72 MPH. We didn't have overdrive top gears then. The Rambler was a 3-speed manual, the Javelin was a 4-speed. Top gear was a 1:1 ratio. The way the government economy tests were set up in the early days, just adding on a 5th gear as an overdrive and dropping the RPMs, along with an engine designed to produce maximum torque at low RPMs, was the way they went about generating good numbers on the tests. 60 MPH cruise in my '88 XJ is only around 1600 RPM. It's really operating BELOW the torque peak. I think I would get better fuel mileage if I were to swap in 3.54 or even 3.73 gears ... but with 273,000 miles on the thing now, it doesn't make a lot of sense to be dumping big money into it. This is also why people who liked to drive at RPMs much higher than the engine's torque peak couldn't match the official fuel consumption numbers. I never had a problem. I always did better than the official numbers. (The '88 XJ 4.0L was NOT rated at 28 MPG, which I got once, or at 24 MPG, which I could repeat regularly. I still get 22 MPG highway.) Once Chrysler took over, they were more interested in selling to people who wanted speed and performance, so they designed the vehicles around different parameters. We all realize that a Jeep with a torque peak at 4,000 RPM is rather silly, but if it spends most of its time on pavement and it's fun to drive ... we sort of ignore that elephant in the living room.

Because the Renix engines weren't designed to run in that RPM range. There are three (or four) “generations” of the 4.0L engine. The “first generation” was introduced in the 1987 model year. This version used a Renault/Bendix (“Renix”) designed, multi-port fuel injection system. The original 1987 model was rated at 173 horsepower at 4,750 RPM and 220 foot-pounds of torque at 2,000 RPM. The horsepower rating for this version was raised to 177 horsepower at 4,750 RPM and 224 foot-pounds of torque at 2,400 RPM for model years 1988 through 1990. As a result of the various changes Chrysler made in the 1991 model year, the second version of the engine (the original HO) was rated at 190 horsepower at 4,750 RPM and 225 foot-pounds of torque at 3,950 RPM. The increased horsepower was perceptible in street driving, resulting in an engine that “felt” considerably faster than its predecessor even though it was not, in fact, significantly faster. However, the horsepower increase came at a price: although the rated torque was unchanged, the torque peak was now at nearly 4,000 RPM, which is higher than the engine would likely see in daily street driving, and considerably higher than what is desirable for off-road use (other than mud bogging). The “third generation” 4.0-liter engine: In 1996 DaimlerChrysler again revised the electronic engine controls, to comply with a Federal mandate to make all vehicles OBD-II compliant. The horsepower rating for the 4.0-liter engine remained unchanged at 190 horsepower at a slightly lower 4,600 RPM, but the torque peak RPM was lowered, to 225 foot-pounds at 3,000 RPM. An additional running change was introduced in the Grand Cherokee in model year 1999 and in the Cherokee for model year 2000: the single ignition coil was eliminated and ignition was handled by a coil rail system, in which each spark plug has a dedicated coil mounted to a rail directly at the spark plugs. This arrangement eliminates the high voltage spark plug wires of older (“conventional”) ignition systems. The author considers this to be a variant of the “third generation.” However, it can be argued that the change is sufficiently significant that the 2000 and 2001 (and 1999 Grand Cherokee) 4.0-liter engine should be considered to be the “fourth generation” of the design. This version produced incrementally more power than the preceding version: 193 horsepower at 4,600 RPM and 231 foot-pounds of torque at 3,000 RPM. The 1991 HO engine had completely different heads with a higher flow and higher ports, different intake and exhaust manifolds (which you negated by going to aftermarket headers), a tweaked cam profile, and a different ignition and injection system using larger injectors and a completely new fuel map. The HO engine is operating near its "sweet spot" in the 3,000 RPM range, which is while it feels so much stronger than a Renix from 3,000 to 4,000 RPM even though the horsepower ratings are virtually identical. The Renix engines are in their sweet spot between 2,000 and 2,500 RPM. You can feel it when you drive it. Mine will rev past 2,500 ... but I'm not doing anything at higher RPMs, I'm just making noise. What I consider to be the "natural" shift point is around 2,250 RPM. By contrast, my 2000 XJ 5-speed really likes to be shifted at 3,500 RPM, and hills I can drive up in 4th gear with the old Renix at 30 MPH require downshifting to hold 30 MPH with the new 2000. You really cannot extrapolate from one engine to say anything meaningful about the other (except that they're both Jeep engines and will run forever if you change the oil).

djag12 -- You should be able to just put your old speedo in the "new" cluster. The gotcha is that the base models with idiot lights also don't have a trip odometer in the speedo, and most folks doing the cluster swap want the trip odometer. If your cluster has gauges but just has the big fuel gauge where the tach should go, then you already have a trip odometer and you can swap the speedo into the new cluster. RamRod, we need to know more about what year your MJ is, what cluster it has, and what year and model your replacement cluster is. Those articles on NAXJA are about rolling back the odometer, but there's no need to do that if you can simple swap the speedometers. Plus, if you keep the original speedo in the vehicle (even in a new cluster) then there are no legal ramifications, because the speedometer hasn't been tampered with. There's no law prohibiting replacement of oil pressure and temperature gauges.

could you PM it to me please. My old speedo is different from my new one and theres over 200k difference between the two. How are they different? Are they from the same year? If the way the speedo cable attaches is different, you may have no choice. You may HAVE to use the old speedo. Photos would help -- front and back of both clusters.

Now THAT is a brilliant solution. :clapping: :cheers: And the standard Jeep sender for any base model with idiot lights will do exactly that.

uh ya ,i got the computer controled carb , the califorina model I believe the 49-state '86 I had also had a computer-controlled carb, but I don't remember any check engine light. What the heck does "MIL" stand for?

Why not just put your speedo in the new cluster?