500-comanche

Ok guys, I need a little help with my memory. It looks like I will be resurecting the MJ after all. It's an 89 that needs a new engine. It has an AX-15 and is 4x4. If I wanted to go to a HO 4.0L do I need to watch out for one that was matched up with a 5spd? What would need to change if it was an engine out of an xj with an AT? I used to be pretty well versed in this stuff, but I guess after 2 yrs and a new born baby my memory is shot. Thanks

I think ur doing the right thing. If ur not comfortable with it and don't have the facilties to do it, I wouldn't attempt it either. I am doing my first 4.0 swap, and I wouldn't say it was easy in the least bit, and I just got out of a year of votec auto tech! That year has about a mile of vaccum hoses to figure out. labeling helps, but overall, it is not an "easy" swap IMO.

I finally got the 4.0l out of my mj tonight. It took so long and I was so cold and tired, I didn't even get a chance to see what happened to it. Tomorrow it gets gutted and I can see which ring I lost. Those two star bolts at the top of the eng/tranny mounting hardware are a royal pain in the.... I think I will be taking the tranny out and then putting them back in together. Or is that a bigger pain than just doing it the old fashion way? I hope I can remember where each of the million and half vaccum hoses go! I am leaning towards a reman. engine. I have done some research and I think this will fit my needs the best as far as time/budget. It's still going to to be a few months anyway before I can afford to much of ANYTHING to it. But I can't wait.

Not sure if u have done this yet, but try just adjusting it first. There is a great article at jeepforums.com in the cherokee tech FAQ on how to do it. IT may be in this forum too, but I saw it over there for sure. It will go a lot faster/more accurate with a voltmeter.

OK, well I finally got this fixed. What I did was clean the the throttle body by removing it and taking both sensors off. I cleaned every hole and orifice ;) with carb cleaner and paper towels. I used almost a whole can and cleaned it up really good. When I took the TPS off, I didn't notice how it was set, and had to adjust by repeated trial and error. It took about 20 times of loosening and tightening the sensor and moving it a tiny bit until it would run well. I don't have a volt meter so I had to do it this way. I will have one to use tomorrow and will adjust it the right way. Regardless, the RPMs never drop below 1K now! W/ the meter, I can set the TPS so it idles a little slower and runs a little smoother. I don't know which one helped more, the TPS adjustment or cleaning the T body, but it works much better now. My guess is the TPS adjustment is what helped the most. Anyway, thought I would let everyone know the problem seems to be fixed! :D

Nothing mentioned so far would account for a 6+ mpg loss, except for the brakes. You mentioned that you replaced the 02 sensor. That would have been my 1st guess. Are u sure it wasn't cracked during installation? Possibly, you got the wrong 1? Are there any other factors? How does the engine run overall? Does it have normal power? Check ur O2 sensor again. I'm not sure if ur engine is L-EFI controlled or not (L-EFI is FI with airflow meter that checks the amount of air flowing through the intake manifold). The meter might need to be replaced.

extended brake lines. If ur only going 2" in the rear you probably don't need to change your pinion angle. I went 2 in the front and rear and haven't had any problems. If you go 3 in the rear, i have heard you need to change the pinion angle. Other than that, you should be OK as far as I can think. Ur control arms will be fine, u may need a track bar extention for the front, but I'm not sure.

Well, I will try to keep you all updated, but it will be a while. It happens a couple of times per trip so I will have to live with it. I am way too busy this week to take care of it due to a bunch of new issues this week. Thanks for all the input everyone, I'll let you know what's up ASAP.

Yes, it will recover if I give it a little gas (IF I CATCH IT IN TIME OF COURSE!). So you think it's the TPS? That would make sense. Any special tricks/warnings to replacing it? Thanks for you help!

It stalls when I have the clutch depressed. I am coming to a light and I push in the clutch to put it in N or down shift or just hold the clutch in to coast. The RPMs drop down all the way down till it stalls, or it recovers. It pretty much runs great other than that.

I have an 89 MJ w/ 4.0L and 5-spd AX-15. When I take it out of gear to neutral, then the rpms drop- sometimes to the point it stalls. I don't think that it is fuel related. I was thinking it might be a vacuum problem or maybe the EGR? Would appreciate any input you fellars might have. Thanks.

I have an 89 MJ with a 4.0. A few weeks ago I rearended someone and had to put a new rad in it. Everything went fine and seems to work fine. The engine temp seems to be cooling fine. It takes about the same time to warm up as it used to. However, since then, I get very little warm air out of the defroster, and no warm air blowing through the lower heat ducts. If I turn the selector to defrost, moderately warm air comes through the defrost vents at the correct level of flow from 1-4. When turned to heat, no air flows through at any of the levels, but the defrost still works (esentially no difference between defrost and heat settings). What would cause: 1) only moderately warm air to come out of the defroster on defrost 2) No air to be pushed out of the lower heat ducts on heat

:yes: :clapping: :yes: Good one!!!

I have had really great luck with the Dupli-color Truck bed coating in a rattle can. It costs about $8 a can. I bet about 1 or 2 cans would do the trick. I would give them a light sand with finer grade sandpaper and spray them with some POR. Then spray on the bed coating. It applies better this way than herculiner too. It really comes out well and looks good. It really doesn't run at all either! (within reason of course). I don't think I would actually ever use it for a bed liner, but I sprayed my grill, blinker brackets, etc. and they look great. I just sprayed my bed toolbox with it, and it looks really good too because it doesn't run. Test it first on some metal though. If u change your mind, it could be a real :mad: to get it off! Remember, it's not AS tough as Rhino or herculiner, but it IS pretty tough. :chillin:

Yikes! Well I understood a bit of what you all said. I now realize that this is 10X more complicated than I first thought. I would still like to attempt this someday. Fortunately, I know a retired mechanic who spent 30 years working for WA state as a master mechanic and has forgotten more than most mechanics will ever know. I am sure that he can answer this question, but I will ask you guys (again). Can I use the running gears out of a newer rig with a D44 and slightly used gears?