Eagle

All the radiators are set up for automatics. Crawl underneath and you should see two plugs along the bottom of your radiator. While you're doing the conversion, you might as well go all the way and install an auxiliary tranny cooler for insurance. BTW, if you bring over the '92 radiator, you'll gain a filler neck but you'll lose a place to put your auxiliary fan switch. The 92 radiator doesn't have a bung for the temp sender in the driver's side tank.

The factory timing chain is NOT a POS. It's a single roller, which is more than adequate for a torque engine that doesn't see high RPM and doesn't have dual coil, high-pressure valve springs. I pulled the timing assembly from my '88 XJ at 200,000, not because I was having problems but because I remembered that the cam sprocket on my AMC V8s had nylon teeth, and they liked to strip after a few years or a hubdred thousand miles or so. So I figured I was living on borrowed time and that a full replacement would be a preemptive strike. When I took it apart, the old timing set was in perfect condition. I learned that the large sprocket on the 4.0L is all steel, so no worries about stripping the teeth. The original chain was tight enough that there was virtually no difference between it and the new one. I was in these so I installed the replacement, but I kept the old timing set and I wouldn't hesitate to put it in an engine that needs a timing chain.

Friends don't let friends buy Rusty's products. Been there, done that.

Stock shocks should be fine. Depending on which one you get, they offer (in front) 7" to 8" of total travel. Assuming the stock configuration splits that equally between up-travel and down-travel, that's 3-1/2 to 4 inches each way. Put in a 2" lift and you move that to 1-1/2 up and 5-1/2 down. Still enough travel for normal driving, just a bit less droop than optimal for severe off-roading.

Sounds like either weak spark or out of time. Check out Cruizer's list of sensor checks for how to determine if the CPS is putting out the correct voltage. Just because it's new doesn't mean it's good -- there's a lot of DOA stuff in the way of electrical components.

I just spent a couple of hours going over the Monroe on-line data and a printed catalog from Rancho. The mount codes for the XJ/MJ front shocks are S1 (or S4 in the newer system) for the upper end, and XP4 or XP7 for the lower end. After scrolling through the entire list of shocks by dimension. I found that the XJ/MJ replacement shocks are the longest offered with those mounting codes. There is some variation, depending on which shock series you're in, and I also found that in some series there are more than one shock number with the exact same dimensions. Dunno why -- different valving, perhaps? I have this compiled in a spreadsheet. If anyone has a way of posting it in a format where everyone can see it, drop me a PM with your e-mail and I'll send it to you. The bottom line for the longest available is the following, listed with the mid-travel length for each. Stock mid-travel runs from 16.188 to 17.188. Monroe 37083 ... 17.188 OESpectrum (Listed for 91-92 MJ and 91-01 XJ) Monroe 911161 ... 16.875 Reflex (Not Listed for XJ & MJ) Rancho 17041 ... 17.188 Rancho RSX (Listed for 91-01 XJ & MJ) Monroe MA822 ... 19.438 Max-Air (Listed for 84-01 XJ & MJ). This is the longest Monroe shock listed with the correct end fittings, and it's an air-adjustable shock -- which may not be appropriate or acceptable for many people. Link to Monroe dimension chart: http://www.monroe.com/assets/downloads/english/MonroeMountingLengthSpecifications.pdf Edit to add: I did a screen grab of the spreadsheet. It may be a bit small for reading, but let's try it:

Most people I've known with budget boosts just run the stock shocks. There are other options to adapting for a budget boost, but your anticipated use has to be factored into the equation. One approach (at least for the front) is shock stud extenders: http://www.summitracing.com/parts/mrg-1290/overview/ They're cheap enough at $12 for the pair. But if you plan to wheel hard, with the suspension fully articulated, these won't be a good choice because you'll risk bottoming out the shocks before the suspension hits the bump stops. For street and mild wheeling they should be fine. I'd suggest just going to the specifications section of Monroe's catalog and looking for a shock that fits your needs. Hornbrod posted the following: Based on those specs, the shock travel is 7.875" and the mid-height (which is where the shock should sit at curb weight on a level surface) is 17.188". So look for a shock that has a mid-height of somewhere around 17" and a stud at the top and a bar pin at the bottom. Once you find one or more shocks that will work, you can jump to the cross-reference part of Monroe's web site and see what vehicle(s) the shocks fit. Once you know that, you can use that information to shop other brands of shocks if you don't like Monroe. (I happen to like Monroe, FWIW.) Keep in mind that, as with stud extenders, you'll either have to restrict your wheeling or extend your bump stops to prevent bottoming out the longer shocks if the suspension compresses.

It's all exactly the same. All MJs used a high pinion D30. All MJ suspension and steering components are the same as XJ. It's not an upgrade in any way, but it should be an easy bolt-in swap.

Let's take it from the top. You wrote that you took parts from the XJ to get the MJ running. What parts did you take? And, since it ran before and doesn't run know, what did you use to replace the parts you "borrowed" from the XJ? In theory, the three things an internal combustion engine needs to run are fuel air, and spark. You have all three, so the answer has to be somehow related to timing, either of the ignition or of the injection. Have you tested the fuel pressure in the rail? Have you tried starting it with starting fluid, or by pouring a SMALL amount of gasoline directly into the throttle body?

Can you see the timing mark on the front cover? You have spark, but have you confirmed that #1 is firing when #1 is supposed to fire? Spark plug wires in the correct firing order (1-3-5-6-2-4, IIRC)?

If it's a 1988 or newer, try bypassing the ballast resistor.

What are the symptoms when it doesn't come on? Does it die when running, or not start, or ...?

See post #1.

It's a 2.5L, so it's throttle body injection. Are those the wires for the injector?

At some point the paint color tag was on the upper radiator brace. I don't remember if that was the "new" position, or the "old" position. There should also be a tag on the driver's door that includes, among other information, the paint code.

One other advantage to the LP Dana 44 is that you can go deeper with gearing. With the Dana 30, the lowest factory ratio was 4.56, and the lowest available from the aftermarket is 4.88. Beyond that, the pinion would get too small.

It's blowing fuses because you are using more current than the fuse can carry. That's what fuses are for -- to prevent the wires from burning up. Did you try any of the trouble-shooting suggestions you've been given?

More like 20+ years. The XJ has been out of production for 13 years.

Early XJs built in Venezuela (for their domestic market) had D44 front axles.

You may like the look of the Waggy grille, but you WON'T like the lighting. Those headlights are smaller than the usual quad headlamps, and they give off about as much light as a single candle on a birthday cake.

Two thoughts, for starters. First, a slight stutter under load is often caused by bad spark plugs and/or bad spark plug wires. Second point is that the early (non-HO) 4.0L engines don't have the same power curve as the new ones. If you haven't yet owned one with a distributor, that means you haven't owned anything older than a 2000 (or maybe a 1999 if you had a Grand Cherokee). The Renix era 4.0L (1987 thru 1990) is not the seat-of-pants rocket ship that the newer ones are. There's a reason why Jeep called the second generation "High Output" when it was introduced in 1991. If you are expecting a Renix-era 4.0L to give you the same seat-of-pants feel as the 2000+ versions ... forget it.

Me too. 3.73s with 31x10.50-15 tires is exactly the same final drive ratio as a stock automatic on 225/75-15 tires. IMHO 4.10s is about optimum for 31" tires. I wouldn't even consider running 33s with 3.55 gears.

^^^ Truth. The RMS for the 2.5L 4-cylinder requires pulling the transmission. The 4.0L 6-cylinder does NOT require pulling the transmission, and doing so will not get him access to the seal. You have to drop the oil pan and remove the rear main bearing cap, and you can't do that just by removing the transmission. I understand that this guy is your friend and he thinks he's doing you a favor, but ... he's not. He obviously doesn't know jack about Comanches, and he's probably going to mess something up dropping the transmission unnecessarily. That means it's going to take him two or three times as long to do the job as he thinks, and on top of that $14 seal you'll still need to buy a new pan gasket. (Hint -- get the '95+ one-piece pan gasket -- it works MUCH better.) Either do it yourself, or take it to a shop that knows how to do it.

If it's blowing fuses, you have a short circuit somewhere. Find the large(-ish) connector where the rear harness plugs into the chassis harness. Unplug it, then try again. If it still blows fuses, that's not the problem area. Then disconnect the front light harness and try again, Rinse and repeat as necessary. You need to isolate the problem to a smaller universe than the entire truck, or you'll drive yourself bonkers just chasing things around because somebody said, 'Try ___."

'87 4.0L 5-speed on stock tires: 3.07 '88 4.0L 5-speed on 31s: 3.73