Eagle

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?

What are you looking for -- torque and gas mileage, or noise and high RPM? My brother talked me into putting a 2-1/2" cat back on my '88 XJ the first time the exhaust rusted out. It sounded nice, my gas mileage went down the toilet, and I could feel the loss of torque off the line and throughout my driving range (it's a 5-speed, so it never sees more than 3,000 RPM and only *very* rarely sees higher than 2,500 RPM). IMHO, the stock 2-1/4" is the preferred setup. That had to be the only time in my long life of playing with with cars that I was actually hoping for an exhaust system to rust out so I could justify replacing it.

MIL? Check engine light ... on an '86? The 49-state models didn't have any check engine light in '86 ... or in '87, '88, '89 or '90. You have a check engine light?

One thing you might try is gelatin. Not "Jello," just plain, powdered gelatin. Some health food stores have it in capsules, and some of the mail order vitamin places also sell gelatin caps. I was turned onto it by an electrical engineer many years ago. His wife had had multiple spinal fusions and then tried the gelatin caps. Apparently (according to him) the gelatin helps to pump up damaged discs, and lets them do what they are supposed to do again. I take two every morning and I think it helps my chronic back problem. Even if it doesn't -- it's also good for your fingernails and your hair.

Why mod a GM? Jeep was using a high-energy ignition for years with their carbureted engine. Just get the ignition out of any 2.4L Wrangler or any AMC car with the 232 or 258 in-line six. All you need is the distributor and coil, I think. I don't remember there being any supplemental "ignition module".

except the gc has OTK steering...which is better for drive angles with lift. Whats WJ's not ZJ's.. They had the same LO-Pinion D30 as the TJ. So the knuckles would be a direct fit as long as you watch the rotor dates as Eagle pointed out. CW Considering ZJs weren't made until 93 I don't think it'll be a problem. It would be a big problem if you tried to use ZJ hubs and/or rotors on an 84-90 XJ or MJ.

?????? Connects with the flywheel teeth? The CPS doesn't connect with the flywheel. It sits right next to it, such that the high spots on the perimeter generate a magnetic pulse when they spin past. The pule is converted to a very low electrical impuls (I think it's 0.5 volts a/c, IIRC). Be careful to route the wire on the new one well clear of the exhaust manifold or the insulation will cook and the wires will short out.

except the gc has OTK steering...which is better for drive angles with lift. You sure you're looking at a 95 ZJ Grand Cherokee? They used exactly the same front axles as XJs of the same year, AFAIK. Except, for some screwball reason, the ZJs were low pinion and the XJs were high pinion.

That's not how you test a Renix CPS. You should test for A/C volts when cranking.

They should be the same parts. The break in the XJ/MJ front knuckles/hubs/rotors was between 89 and 90.

YOU THERE! JTDesigns! Put your hands in the air and step away from the keyboard. NOW! Don't make any sudden moves. Everything's going to be fine -- nobody needs to get hurt. Just keep your hands where we can see them, back away from the computer and tell us what you've been taking ...