Eagle

The elongation I think I saw was horizontal. Certainly, upper control arms are the other suspect. I initially discounted them as a prime suspect because I've never seen one go bad, but there have been so many things wrong with this 2001 XJ that I've never seen even on vehicles 15 years older and with three or four times as many miles, I probably should assume that they need to be replaced, since everything else in the front suspension has needed to be replaced. Talk about "Just Empty Every Pocket" ...

This happens to be for the "new" 2001 XJ, but could as easily be for any MJ so I'll put it here: Had a lot of clunking under the floorboards when driving over pavement cracks and washboard roads, so I cleverly diagnosed lower control arms. I could grab 'em by hand and move them around, so it seemed like a valid diagnosis. Changed them out with a set of new OEM style (Crown) LCAs over Thanksgiving. There's a lot less clunking, but I'm still getting some, and I can still feel things in the steering shift slightly when I hit a diagonal crack or a bridge joint. I've already replaced the ball joints and tie rod ends, and the track bar is good. Soooo ... Has anyone encountered egged-out holes in the caster adjustment clevises that go in the rear (frame) LCA pockets? I didn't pay as close attention as I probably should have, but I have a sort of fuzzy recollection that the clevis holes seemed elongated -- and they're supposed to be round. Before I take things apart again to replaces the clevises ... is this something that anyone has seen? Does it sound like I'm on the right track?

Yes, it could. There is one other, oddball possibility. If the PO replaced the water pump, he could have gotten one for a 4.2L engine with vee belts rather than a serpentine belt. Externally they look alike and they both bolt to both blocks, but the direction of rotation is reversed for the serpentine belt, so the impeller vanes go the other way.

Plugged radiator.

Fuel filter? O2 sensor?

Happy Thanksgiving to everyone. I hope you all have time between the feast and the football to remember something in your lives for which to be thankful.

I'm accustomed to paying around $100 apiece for the front unit bearings. Sounds high, but they're good for 150,000+ miles, so it's not too bad. FWIW, the early style can be rebuilt -- Quadratec sells the individual bearings and seals (two of each required per hub). The total cost isn't that much less than a new unit, and you need a 12-ton or 20-ton hydraulic shop press to do the work.

Probably the cushion on the transmission support at the crossmember is compressing. This allows the exhaust pipe to make contact with the crossmember as the engine flexes relative to the chassis. You could replace the tranny support (big $$$), or you could shim it.

The bearings are inside, that's why it's called a unit bearing. If you are getting a "deal," be sure it's the right one for your year. They are not all the same, and they do not interchange.

No, you don't. There are three wires to the fuel tank. The heavy one is power to the fuel pump. the black is ground. The third is for the fuel level sender, which is obviously also inside the fuel tank.

After it has sat overnight, when you turn the key to the RUN position (not START), does the fuel pump run for a few seconds and then shut off?

Huh? ???

That's very possible, the the way to test that is a noid light. But the CPS controls both the ignition and the injection, so if there's a signal to fire the spark plugs, the problem isn't the CPS.

I don't know what Texas requires, but all XJs and MJs had catalytic converters. If you are doing a complete exhaust, I would install a cat. As to the best sound, IMHO the only aftermarket exhaust system for the Jeep I-6 engine that doesn't sound like crap is Gibson.

Slow down, and help us by giving enough information to diagnose. You may have more than one problem. First: the blower. Does the fan run? If the resistor pack is bad, it should still run at full speed with the control is moved to HIGH, because the resistors reduce the speed. High speed doesn't go through a resistor, so that should always work even with a blown resistor pack. If the blower runs on high, you need a resistor pack. If the blower doesn't work at all, go to the engine compartment side, unplug the connector to the fan, and try hot wiring it with a separate ground and a wire right from the battery. If it doesn't run at all, you need a blower motor. Not a surprise if that's the case -- the motors use brushes, and they do wear out. Second issue is where the air comes out. As noted, the controls are actuated by vacuum. Even a small vacuum leak can stop the heater controls from moving the flappers. The default is to send air to the top-of-dash defroster outlets. If you have a blower motor that works, and the air is coming out of the defroster outlets, you need to look for a vacuum leak. Third is that the Renix years (which includes the '88) have a vacuum controlled valve in the coolant line leading to the heater core. Make sure that valve is functioning (or just bypass it). Last is that the heater core is now 25 years old. It would not be a surprise if it's completely clogged, especially if it hasn't been maintained. You may be looking at a heater core replacement. If the dashboard is already open -- do it anyway, as a preemptive strike. When the heater core springs a leak, it dumps coolant into the passenger side footwell. It's not pleasant.

??? It starts when the key is in the START position, so the fuel pump must have a ground. The problem is that he's getting power to the fuel pump through the starting bypass circuit, but the fuel pump is NOT getting power when the key is in the RUN position. So how do we trouble-shoot that? For openers, although the ballast resistor has been replaced and then by-passed, I saw no mention of testing the circuit. You've got two nice, big, fat contacts there so I would begin by putting the key in the RUN position and check to see if you have 12-volts at the ballast resistor. (Actually, it'll be 12-volts on the upstream side, and something like 8 or 9 volts on the downstream side.) If you have power at the ballast resistor, then look at the wire from there to the fuel pump. If you don't have power at the ballast resistor input side, then trace back upstream from there.

You don't have a choke -- you have fuel injection. If it fires when you dump gas in, then the CPS is good and the throttle body doesn't have a problem. You are confusing people by saying it won't "fire." If you have spark and it starts when you pour gas into the throttle body, it DOES fire. You aren't getting fuel, so it won't stay running. I'm also confused by your statement that it doesn't accelerate. If it only starts when you pour gas into the throttle body, how can you drive it? Accelerate is when you increase the speed of the vehicle on the road. If you can't drive it, you can't accelerate.

Stock is 2-1/2" up to the cat -- and out of the cat. The connector from the cat to the muffler necks down to 2-1/4", and the muffler inlet is 2-1/4". I don't think the change to an HO will make the exhaust sound any different at all. I used to spend a lot of time on trail rides watching different XJs negotiate obstacles, and they all sounded pretty much the same. It isn't very exciting, because with an in-line 6 the power pulses are all perfectly evenly spaced, so the exhaust can never get that lumpy "cammed" sound you get with V8s. I ran a 2-1/2" turbo system on my '88 XJ for awhile and I hated it. It was louder than stock but didn't sound any better, plus it hurt my low-end torque and cost me gas mileage. It was the first (and last) time in my life I actually looked forward to the day when I needed to replace the exhaust system. If you want a Jeep I-6 to sound good ... go Gibson.

The routing has to be different with the XJ proportioning valve. With the MJ metering block, if you eliminate the rear proportioning valve the new single line to the rear comes out the nose of the metering block. The XJ proportioning valve doesn't have an outlet there. For the XJ proportioning valve, the rear brakes get connected to the port you would plug on the MJ metering block. (Bottom/front)

A manual override is much easier. On your schematic, do you see the original radiator sensor? It's a switch. You'll be abandoning it anyway, so you should have a two-conductor plug where the bung sensor connects to the harness. Just plug two wires into that plug and run them to your toggle switch.

No. Proportioning valves are used to alleviate having too much braking at the rear, with resultant premature rear wheel lockup and spin-outs. The easy solution is to use very wimpy (or no) brakes on the rear -- but then you have insufficient brakes when the vehicle is fully loaded.

I still think it's related to the XJ proportioning valve. One of my NAXJA friends always had a very soft peddle in his XJ trail rig. He replaced just about every possible component in the system (except that proportioning valve) to no avail. Finally, he ripped that out and installed a Wilwood manually-adjustable proportioning valve in the line to the rear, and that cured his problem. I don't like the XJ proprtioning valve in XJs, and I think it's a huge mistake to put one on an MJ, but you've already done it so we have to go forward from there.

On the front of the XJ proportioning valve there's a plug, with a vent hole through it and a rubber cap over the vent. Under that is a spring-loaded plunger that does the actual proportioning. The plunger has a rubber O-ring on it. That whole plunger/O-ring gizmo sometimes gets gunked up and won't move, which results in no brakes at the rear. I would start by CAREFULLY (that spring is strong) removing that assembly and swabbing out the bore with brake clearer and Q-Tips. Clean up the plunger, spring and O-ring, then reassemble, re-bleed, and try it.

The reality is that we rarely to never have to actually tap a new hole or thread a new rod, we're always chasing rust and/or burrs out of existing threads ... and nothing destroys dies faster than chasing rusty threads. I'm doing this now on the threads for the caster-adjusting clevises in the lower control arm pockets -- cleaning up the threads so that maybe I can have a fighting chance of getting the flange nuts looses without snapping the studs. Did one side yesterday, I'll do the other side as soon as I get a chance. I think the Harbor Freight sets are ideal for this, because I don't feel nearly as bad chewing up a cheap Chinese die as I would abusing a good American die that way. And we really don't need top quality for chasing out existing threads anyway. Heck, I just checked the Harbor Freight web site. Those 40-piece sets are on sale for $14.99 right now. At that price, if you destroy one tap or die it's almost cheaper to just buy a whole new set than to go out and buy singles. http://www.harborfreight.com/hand-tools/tap-die.html?dir=asc&order=price

I thought you wanted to retain the function of the rear height-sensing valve. If that's correct, you have TWO lines to the rear, and you need to keep them clearly differentiated so you don't totally FUBAR the way your rear brakes [used to] work. See Pete's photo: . The line coming out of the "nose" of the metering block is the one that normally feeds the rear brakes. That feeds into the rear height-sensing valve, and the pressure it sends to the rear gets modulated ("proportioned") by the height-sensing valve. Below that, the one in Pete's photo that has an arrow with the caption cut off has the line removed and a plug installed. That's the outlet for the rear brake bypass, and it normally has a second line going to the rear that goes into the rear lines downstream from the height-sensing valve. The purpose is so that in the event you lose the front brakes, if the bed has no load the height-sensing valve allows almost no braking in the rear. The bypass allows the rear brakes to operate at full pressure if the fronts fail, so you at least have some brakes.