Eagle

Poor fuel mileage can be the oxygen sensor. If it's not reading correctly, it may be calling for the injector (singular because this is a TBI 4-cyl) to squirt more juice than what the engine needs to maintain the optimum air/fuel mixture. Last time I replaced it on my '88 4.0L, I knoew it was due because when I would take my foot off the gas to shift (5-speed) I would hear a muffled "POP" from under the floor. That was a small backfire in the catalytic converter, caused by raw fuel that was NOT being burned because the O2 sensor wasn't reacting to the change in engine conditions quick enough when I dumped the throttle and disengaged the clutch. How old is your O2 sensor?

'94 YJ Wrangler

Well, CW, it appears as if we are just going to have to agree to disagree :shake: It appears as if in every tire thread, you tout domestic brand name tires... Where in his ONLY post in this thread (quoted above) does CW say anything about domestic brand tires? Even as a tire shop owner/manager, how can you possibly DISagree with "Stop in your local retailer and ask to see whats most popular and go for it"?

You da man! :bowdown:

I would think it could be made up out of some copper tubing, a sweat tee, and a little ingenuity.

Two points: First, the scale on the temp gauge is not linear. There is no marking for 190, so you have no way of knowing where 190 is on the scale. More importantly, the temp sensor for the gauge is at the top back corner of the head. If you are low on coolant, that's where there will be an air pocket. The sensor will not be in flowing coolant, so it won't react quickly to the engine heating up. By the time it thinks it sees 190, the actual temperature will be significantly higher.

It is possible and it has been done. Potential obstacles to be addressed: 1. Front fenders aren't really the same, when you look closely. To mate up properly with the "new" header, you'll have to buy a replacement fender for hers that got crunched. 2. Dashboard mounts are slightly different, so I've been told. There are threads on this site of other people who have put the new dashboard into an MJ, so it can be done. 3. Brake & taillight wiring for the MJ is different than for the XJ, because the MJ doesn't have amber turns. Even when using an older XJ harness, there's going to be some adapting needed where the "new" chassis harness ties into the rear portion of the MJ harness. 4. Location of the door strikes/catches moved. This has also been addressed on this forum.

Pete, some aftermarket company (I'm sorry, I don't remember which one) used to offer that lower hose insert as a part. Several folks on NAXJA used it for just this purpose. Naturally, it was discontinued about four or five years ago. Don't know if any other company has picked up on the idea.

Don't think it's a solenoid. The AW-4 does have solenoids for controllers, but if you pull the fuse for the TCU it should still shift manually -- just won't have second gear. The '98 I think doesn't have a separate TCU, I think in '97 they went to a combined PCU (Powertrain Control Unit) but the actual tranny operation is the same. But that price for a '98 with low miles is still a steal. Grab it, buy a junkyard tranny for it, and never look back.

Not two ratios, but two types of attachments for the speedometer cable to the speedo head. The early type was from 1984 thru 1986, the later type was 1987 thru 1990. After 1990 the speedo is electric. I still think the change may have been in mid-year 1987 rather than a clean 1986/1987 break, but I haven't been able to verify that.

That's because the oil gets thinner when it's hot. But don't run it if you don't have coolant in it.

No. Not related to using 4WD. But unless you have converted, you have the "closed" cooling system. Those are VERY difficult to get all the air out of after working on the cooling system. One of the symptoms of not enough coolant is no heat. It seems contradictory that it would overheat yet not generate heat, but when the coolant level is low, nothing gets to the heater core. The engine can overheat, but you'll have no heat. Do a search on "burping" the system.

You mean this? The Corvette sensor? The one that doesn't operate at the right temperature range for what he needs? THAT part number?

Cooper Discoverer AT/S or HT/S The AT/S will be better in snow, the HT/S should give slightly better gas mileage.

Keep in mind that the electrical stuff changed over the years. The front clip will bolt on if you have two good fenders in the "new" clip. The profile at the top corner of the front fenders changed in '97, so just trying to put the new header and grille on with the old fenders requires some customizing. Also, making the '97 side marker lights work will require some wiring modifications. As to the interior -- your 90 has a mechanical speedometer. The '97+ Cherokees are have electric speedometers, and the polarity of some of the gauges has been reversed (IIRC, specifically the fuel gauge). You can bolt a '97 dashboard into a 90 chassis, but making it work is going to require getting into the interior wiring. The seat pedestals for the 97+ XJ are different from the MJ and different from the early XJs. You can't even bolt the 97 seats into an MJ without custom fabricating seat pedestals.

IMHO the weak link is the height sensing proportioning valve over the rear axle. Since most of us probably run empty or nearly empty most of the time, IF that thing is working, you probably have almost no rear brakes most of the time. If the rear axle has ever been serviced, there's a good chance the actuating rod has either disappeared or been reinstalled wrong and you either have no rear brakes, or no clue what the proportioning is. Then there's the fact that when I had to pull a panic stop a couple of years ago, the height sensing valve in my '88 exploded. 1992 was the last year for the MJ, so the newest ones out there are now almost 18 years old. I don't trust them. You can't buy new ones. So I recommend eliminating the valve before it eliminates you.

It may not be the lifters. The 4.0L is not an overhead cam engine. The lifters push on the pushrods, which in turn actuate the rocker arms, which are what actually push on the valves. Over time, all those parts may get a bit worn. If it's just a light ticking, it's probably normal and doesn't mean anything if the engine runs strong. Try removing the oil fill cap from the valve cover and see if the noise is louder. If so, it could be the pivots that the rocker arms rotate on. Another possibility is that the exhaust manifold may have loosened up, especially if it overheated, and the tick is actually a small exhaust leak. If that's the case, simply tightening the manifold bolts may cure it.

You are correct, the HO head is different and the intake & exhaust ports are higher and shaped differently.

Excuse my asking, but can you explain exactly why suggesting a very simple way for someone to get his truck running with access to the aux fan by a toggle switch while he searches for the magic sensor that nobody has been able to find over the course of the last ten years BS? I'm trying to help him get his truck running with a minimum of hassle. What are you trying to do? As to multiple threads, I have no problem with five threads for five questions. Mr. Collins hijacked three different threads with the SAME question, which spread the discussion of one question all over the board. I don't hang out on Pirate. Perhaps you should stay there if you can't behave civilly here.

Ya know -- it's Wednesday, which is a work day. You posted at 9 something in the morning, when most people are at work, and you get antsy and bump your own thread when nobody has responded by mid-afternoon? Why don't you give people a chance to at least get home from work and have supper? Have you ever used the 4WD before? The front is driven by a chain, so 4WD is always noisier than 2WD. The noise you hear may be normal. If you've used 4WD before and this is different or louder, please post a better description. As to the front spark plug, I believe you have to pull the a/c compressor. In the '84 4-banger XJ I had, that was the only way.

The stock unit? It's a clutch-type limited slip, not a locker. No, the CJ had a 2-piece hub. The hub part is separate, and attatched to the axle shaft with a nut to hold it and a tapered spline to keep it from spinning (in theory). The MJ is a 1-piece axle shaft & hub assembly.

The second line is not a return line. That has been a common misconception for many years andnobody seems to know where it originated. In fact, it's an emergency bypass line that allows full (unmodulated) braking force to the rear wheels if the front brakes lose pressure. The bleeding procedure as spelled out in the factory service manual has been posted here (I know -- I posted it). I'm at work and don't have time to search for it, but if you search you should find it.

You won't find it by year. DaimlerChrysler/Jeep changed to the "open" radiator (with filler neck) in 1991. The radiator stayed the same from then through the end of the Cherokee in 2001. The factory "open" radiators did not have the bung. Some aftermarket radiators do have the bung along with the filler neck. It's a matter of shopping until you find one. Perhaps people who have purchased aftermarket "open" radiators new can post what brand they got and whether or not it has the bung.

For the MJ. For the XJ, it's 84 thru 2001.

Murphy's Law: Whatever can go wrong, will go wrong. O'Halloran's Law: Murphy is an optimist.