Eagle

Oh, I agree that ECUs can go bad. But on an 86 MJ the ECU doesn't control power to the radio, cigar lighter outlet, or starter. But the ignition switch does ...

Absolutely. If your truck is in good shape and you have more money than time, you can still buy a complete 3.4L crate motor from Generous Motors and just drop it in. But you should be able to find a viable 3.4L in a junkyard.

Moroso also makes a funky thing that's basically a length of pipe with a radiator fill neck in it. It costs a lot less than the tank I used. You just cut the upper radiator hose, insert this "thingie" into it, and clamp the two sides of the cut hose onto the ends of the pipe. Voila! Instant open system. I think Summit Racing carries that part, too, but I don't have a part number.

There is no adjustment on the clutch, and I think we have established that the clutch isn't slipping. I still think your engine is turning over because the compression isn't enough to hold the weight. I repeat: There is a REASON they build cars with parking brakes.

I do not think that's correct. I am quite certain that the ECU does not control power to accessories like the radio or 12v plug, and I'm pretty certain it doesn't control power to the starter. I think you need to start tracing your power circuits, starting at the battery, following the battery cable to the power distribution block on the right front fender, and from there through the wiring harness. This does NOT sound like a bad ECU. I would also consider inspecting the ignition switch. On the Comanche, the place where you insert the key in the steering column is not the electrical switch. There's an operating rod from the key tumbler down the column. The actual switch is located near the base of the steering column. That switch, or the wiring connected to it, sometimes goes bad. If that's the case, turning on the key may not be energizing any of your circuits.

What gear are you parking in? Be sure to use 1st gear -- 3rd, 4th or 5th doesn't give the engine as much leverage to hold the vehicle against compression.

"Wisconsin thing"? Is that what they call stealing out there? I usually throw the small stuff into a can or jar, show it to the guy at the counter, and he tells me if he doesn't want to bother with it. Once in awhile he adds a buck or three, usually he says not to worry about it. But my conscience is clear that I didn't try to sneak anything out.

Yep. It should have a white nylon vent plug at the upper end.

I'd like to know how the mechanic determined it was a failed CDI -- whatever that is. Any time a Jeep with a CPS dies (and the Renix TBI does have a CPS), that's almost always the problem.

I thought Jeep changed to RC-134a as of 1994. Might have been 1995, but no later.

Second the vote for similar shots. Which side? Also, it'll be easier to compare if all pics are the same size. What size do most of y'all post pics at, 800x600, 1024x768, or 1280x1024? Let's settle on a standard. It's going to be a picture-heavy thread, so I'd suggest that all pics be resized to 800x600 both for consistency (better visual comparison) and for speed of loading the page.

A Center Force clutch would not be a solution to this problem -- if the clutch is the problem at all. The whole point of a Center Force is that it uses weaker springs for lower peddle effort, and then centrifugal weights add clamping force at high RPMs to help the clutch hold. A Center Force would be worse than a stock clutch when parked, not better.

It is physically impossible to put an AX-5 clutch kit into a 4.0L with an AX-15. First, the clutch itself is a larger diameter, so an AX-5 pressure plate assembly will not bolt onto a 4.0L flywheel. Second, the AX-5 has a 1" input shaft and the AX-15 has a 1.125" input shaft, so the AX-5 disc cannot be put onto an AX-15 tranny even if you somehow tried to mate the smaller disc to the correct pressure plate. If your rear main seal or valve cover gasket is leaking, you may have oil getting into the clutch and causing it to slip. Do you feel it slipping when you drive? How's the compression on your engine? Most likely the weight of the vehicle is too much for the compression to hold. There's a reason why they put parking brakes in vehicles. I don't think your clutch is slipping, I think your engine is turning over.

You will need to remove the dashboard to install a cooling coil (evaporator) in the heater box, and you'll need to replace the dashboard HVAC controls with the control unit and vacuum lines out of an XJ or MJ that had a/c. If your vehicle doesn't already have an auxiliary electric fan, you'll also need the aux fan, larger radiator, and aux fan controls.

Wait, wait -- I think I got trapped on this one before. Bahamas. Is your MJ built to U.S. spec, with the throttle body Renix ignition/injection system, or is yours built to the 84-85 spec with a computer-controlled carburettor?

Photos. Bring back photos. Were you able to arrange a meeting with Joop?

A long time ago somebody on the NAXJA forum posted that there's a Honda temp sender that works as a switch rather than a variable resistor. I never followed up on it because I prefer the surge tank approach, but I wondered if you checked with any Honda dealers you might have professional contacts with.

Yes, you can. Except you wouldn't jumper the ECU. On your year, the ECU has nothing to do with controlling the fan. That plug where the two leads from the radiator connect? Just jumper the two terminals of that connector and your fan will run constantly. This one: Why run the fan when it isn't needed? Your vehicle already has a relay for the fan. All you need is a toggle switch and a few feet of 14-gauge wire. You can leave the fan running all the time if you wish, or leave it off most of the time. Remember, the vehicles sold w/o a/c didn't have that second fan, and they had radiators with one less row of tubes. Most of the time you simply don't need the auxiliary fan. It won't stay "super cool" even with the fan running 24/7, because the thermostat will just close and keep the temperature up to 195 anyway. I just read your initial post (in this thread) again -- am I correct in understanding that you did NOT buy the new radiator yet? If not -- why not just make life easy and buy the correct radiator for your vehicle?

DING!

Yes, for the fron the TJ coil spacers are exactly the same as XJ/MJ/ZJ coil spacers. You can also run your original shocks with a 1-3/4" boost, unless your shocks are the SensaTrack model. If they are, the pistol will be riding in the area of the bore that's not grooved, and when the suspension compresses the pistol will drop into the grooved portion. That will make for a rather strange ride. However, there are shock extenders that can be used that will keep the shocks in the normal operating range. You just need to be sure to extend the bump stops so you don't "bottom out" the shocks if the suspension gets fully compressed. These are sold under the Lakewood brand, but I think Mr. Gasket probably has them, as well. The rear shocks have an eye and grommet on both ends, and I don't know of any good way to extend those. The Rancho AAL is only supposed to raise the back on an MJ an inch and a half. The stock shocks might still work okay since they are a longer shock than the front.

BLHTAZ is correct, and this is the reason I also advise people against rushing into the "open" cooling system conversion. You create a lot of problems, yet the "open" radiator has exactly the same core so it doesn't cool any better. This is one of those things that someone once posted was a good idea, and it has now achieved urban legend status that this swap is a "must do" "upgrade" for the early XJs and MJs. I assume you have already bought the new radiator, so you're stuck with it. My suggestion would be to buy a toggle switch and run the aux fan manually. That 2-wire connector coming out of the old radiator is the control switch. If you're sure you'll never need it, you can cut the wires off that and use them to run to the switch on the dashboard. If it were me, I'd save that sensor and just go to the auto parts store and buy a matching connector to use for the switch wiring. Of course, if was me I wouldn't have a radiator that doesn't have that bung. When I replaced the radiator in my '88 XJ last summer, the shop ordered the wrong year and the one that arrived had a filler neck, and no bung for the aux fan sensor. Once I pointed out that it wasn't the right one for me Jeep, the shop sent it back after I declined an offer to take it at their cost. IMHO, this is one of those changes that has no valid reason for being done. Yet no matter how many times the explanation gets posted why it's NOT a good idea -- somehow it seems people only see the articles advising that it's an essential upgrade -- and then they encounter the same problems that have been written up a thousand times and wonder how to solve it.

Johnny is correct on the XJ. Stock measurements were 17-1/2" front and 17" rear, from center of wheel/axle to bottom edge of flare. (Obviously, if you don't have the stock flares you have to find another way to measure.) For the MJ, the front measurement should be the same but the rear should be 21" to 21-1/2" for a 4x4, and 1" less for a 2WD.

JC Whitney used to sell thread-sert kits, and the simplest form of the tool is just a couple of washers and a bolt to tighten while you collapse the sleeve. There's also a local industrial fastener company near me that has them, and the install kit. Here's the page with those products: http://www.nutty.com/rivets.shtml I'm pretty sure they sell mail order, and they're good folks to deal with. It's a toll-free number -- give 'em a call. Note: The inserts are available in both steel and aluminum. The steel inserts are almost impossible to collapse without a hydraulic setting tool. Get the aluminum inserts, and be sure to use anti-sieze on the threads when you install the skid plate.

My '88 had a 4" lift when I bought it, and I hated it. I removed it and swapped the parts to a guy up-state for some stuff off a wrecked Comanche. A 4" lift is just high enough to be a nuisance and not high enough to be effective. If you absolutely must lift, look for about a 2" budget boost. You can use 1-3/4" coil spacers in the front, and a Rancho full-length AAL in the rear. I would get the WJ lower control arms, and I believe Pete did a write-up on the install (they require minor modification to fit an XJ or MJ).

Are you asking about factory skid plates, or aftermarket? All holes for factory skid plates are already there. The transfer case skid uses "thread-serts," which are like industrial strength pop rivets with a screw thread in the center. You insert it into the hole, use an appropriate tool (there are a couple of types) to collapse the sleeve and lock it in place, and it is then a threaded hole for bolting something to.