onlyinajeep726

I will be checking this on mine too since you mentioned it. :idea:

I just saw this post after I made my last one. I didn't think about an inline fuel pressure gauge, but that's a good idea. I could just leave it there and take it for a drive, thus being able to see pressure readings when it starts wigging out.

I was thinking about it last night after I made my previous post, and thought more on the subject. I will see if I can test it for correct pressure. I guess the reason I haven't focused on the FP more is because it idles fine and will take off fine, but then randomly, after I get up to speed, the Jeep just goes nuts (and it doesn't always do it right away or sometimes not at all). Question for you... if it tests fine in idle, is there a way I can test it safely on the side of the road if it starts bogging down and sputtering? I guess what I'm saying is that I assume you have to hook up the fuel pressure meter while the ignition is off so I guess there's no way to do that with the engine running, IE. I can't exactly see if it's the fuel pressure when it begins its spells of erratic running. Either way, I will start doing a round of tests and get back to you. Thank you for your help so far.

Sounds like you and I are having the same problem... I have a thread started and am currently awaiting some more replies if you'd like to follow it. I'm sure that it will benefit you as well. What engine do you have, by the way and is yours an automatic or stick? That thread I was talking about.... http://comancheclub.com/topic/37396-25l-tbi-help/

So, I spent part of the day and some of tonight to diagnose the issues I've been having from this 4-banger... Needless to say, no luck as I am back here for suggestions. What I've done so far: - Swapped the TPS to a brand new one - Removed, cleaned and reinstalled the CPS on the transmission. (Was dirty as hell, just like Cruiser suggested) - Replaced the MAP sensor - Replaced a couple vacuum hoses that were torn Also, I found that the WOT switch was plugged into the CTS on the intake manifold and the harness end of both plugs were plugged into one another, if that makes any sense at all. Evidently, when the original owner had the YJ engine swapped in, they hooked those up wrong. Anyway, now the thing is worse off than it was before... seemed to be fine when I done these things (idled fine in the garage), but the moment I took her out on the road, it ran even worse and I have no idea where to go with it next. Any help will be highly appreciated.

Poor Comanche... it's a hodge-podge of XJ parts and really stupid looking Ford rims... I'd still buy it if it was a little cheaper... Not really worth $2k for the multicolor/multipart aspect.

I'd say that might be a little too low if you are only going to run 33's. Now if you're in the mood for 35's... lol

Yessir!

Just going to give you a heads up... If you a do a 4.0L swap, you're going to have to make some modifications to the front frame support and radiator mounts to make room for the larger engine. It's a swap I'm looking to eventually do if my 2.5L craps out. That, or a Cummins 4bt hahaha. But seriously, AMC changed the engine bay a little to house the I6. If you're okay with swapping a 2.5L, your current radiator will work find and you can use an AX4 or 5 transmission. Either way, you're looking at a wire harness swap and all the controls to go with it. I wish you lived closer, I'd love to help.

I feel your pain on that one... except mine was a D30 and C8.25 with 4.10's for an XJ pushing the wheelbarrow up hill... Yea, that freaking sucked.

Well, for your DW issue, check out the link in my signature below.

Dodge Cummins 4bt... :drool: http://www.4btswaps.com/forum/showthread.php?585-4BTA-powered-92-Comanche-build-specs

Swap in that AX-15! Just my 2¢...

Damn, that's kind of steep for a stock axle... Craigslist seller or did you find this at a junkyard?

Yes, the early V6 2.8L is a crappy, unreliable engine. AMC knew that and replaced it in favor of the more reliable, stronger I6 4.0L. Now, with that said, if you ever decide to replace that 2.8L, you have a few options; some simple and some that require more work. There is a thread on just this on this very forum. Here's the link. "3.1,3.4 Swap For 2.8V6" You could also pull a 4.0L and the tranny combo from an XJ, along with the wiring harness and convert that MJ to what Jeep should have put in it from the beginning. On a side note, the Chevy 2.8L put out less HP than the AMC I4 that also came in the truck. Yes, there's a reason no one wants the 2.8L lol.

I've heard the AMC 20 rear is even more rare than a D44... but yes, this is also an option.

I would think either. A 2WD MJ with the AX4 or 5 just has a longer driveshaft to make up for the difference of the transfer case being missing.

Yes, I forgot to mention that. I'm not sure of all the parts you'll need to complete the tranny swaps, but what I do know is you'll need the flywheel like mvusse mentioned and the pedal configuration brackets, clutch master cylinder, manual tranny cross member and make sure the transfer case spline count is the same (you'll have to research all that, they may likely be the same, I don't honestly know). There's more to the swap than what I mentioned, but that is what I can think of off the top of my head.

You can swap in an AX4 or AX5 from any 4-banger equipped XJ/MJ/YJ. You can find those same two transmissions on another 2.8 equipped XJ or MJ also. The 4-banger uses the same bell housing bolt pattern as Chevy 60° V6's. This also means you can pull a manual transmission out of a Firebird/Camaro that use the 3.4L V6. By the way, if you google "Jeep 2.8L to 3.4L V6 swap", you can find a lot of useful information there on more than just the engine swap itself.

If you can find a Dana 44 from another Comanche (with the correct gears to make it easy, assuming yours is 4WD), then that is your best bet. You can still find a D44 with non-matching gears if you can't get one with the correct gears, but you'll have to bring it to a shop to swap gears, which usually isn't cheap. On the flip side, a F8.8 isn't cheap either, but for different reasons. You'd have to weld on new leaf spring perches and get a yoke adapter to mate it with your driveshaft. But, a F8.8 can be found from a '96 or newer Explorer with disc brakes and trac-lok if you are so lucky. Sometimes even with 4.10 gearing. Other options, you can try finding a D44 from an XJ/Wagoneer (rare, also) but again, leaf spring perches need to be welded bottom side if you're keeping the stock, spring under axle (SUA) configuration. My suggestion... find yourself a Chrysler 8.25 axle from a '97-01 XJ (those are 29 spline shafts) and have a shop cut off the SOA leaf perches and weld on some SUA ones. These axles have a strength near D44 (not as beefy as an 8.8) but can be had for reasonable prices and they are a dime-a-dozen. I believe some '91-92 MJ's used these axles also (the 27 spline version) and those would be a direct bolt in. Keep in mind though that if you go the C8.25 route (either from a XJ or MJ), you will need larger U-bolts (3 inch diameter) and the MJ plates/shock mounts to make the swap. One last thing about the C8.25 option... if you wish to have disc-brakes later on, you can get rear discs components for a KJ/Liberty and those are direct bolt on with no modification.

Yes lol. I actually went through your entire Renix Tips list last night. I plan on testing it and looking for any crude that may have built up on it. I will also check the TPS and MAP... probably everything while I'm at it.

Does it matter if I pull a CPS off of an '89 4.0L with an automatic tranny?

Thank you for the response and the link. I will be reading over it thoroughly after work and see what all I can derive from it. I hope it's something simple; of course, don't we all? haha.

I have an '86 Comanche 2.5L with Throttle Body Injection and a AX4, 4-speed manual. The engine is not the original Comanche engine, but one from a YJ Wrangler from what I would assume is similar in year and function. Anyway, I was driving it the day before last to work and it was doing fine until it warmed up. All of a sudden, it just acted like it wasn't getting gas when I pressed the accelerator. It idled back down and was running rough, but as soon as I tried to give it gas, it would spit/sputter and bog down. It shut off on its own, so I gave it a few seconds and then I started it back up and the problem went away, for a little while anyway. I got about 2 miles further down the road and then the same thing. That time, I cut the engine off and restarted it about 10 seconds later. I made it all the way to work from then on without hesitation. On the way home from work, the same thing happened 3 more times. Anyone have any ideas on what this could be caused by? It has new spark plugs, a clean air filter, fuel injector cleaner and Iso-heet (water remover) in the gas. Edit... I took it for a test drive today with my dad to see what he thinks, and it did it about 4 times just going a couple miles down the street. We both feel as though it something fuel related or sensors starving it of gas. I have noticed a pattern, however. When it begins these spells of bogging down, I will turn of the engine and start it again while I'm coasting (did that all 4 times during today's drive). Once it's been restarted, it runs and drives perfectly fine for a little while until the issue arises again. It's the damndest thing because I don't have a clue how to begin sourcing the problem... I imagine just strictly looking at the fuel system, there are really only four main components: Fuel pump, fuel filter, pressure regulator and TB injector. The FP seems to prime fine and I can hear it running when idled and what not, though I haven't tested it for the 14-15 psi pressure that's needed. The fuel filter looks to have been recently replaced by the previous owner as it appears new from the outside. The TB injector seems to be spraying good and in a conical fashion. I haven't put a vacuum meter on the regulator, but that's next. Also, it's been suggested on CherokeeForum that it could be my TPS. I will be checking that with my digital multimeter. The O2 sensor appears to have been replaced by the PO. So, as far as sensors go, I don't know what else could alter the A/F ratio. I guess the most confusing part of it all is that when I cut it off and restart the engine, it runs fine for a little while. It's very random when the symptom occurs. Anyway, sorry for the long post, but I really need to figure it out soon because I'm about to stop driving my XJ to swap in a stroker. Any help or advice on this MJ issue would be greatly appreciated. Forgot to mention, the PO removed the cat and just ran a pipe to the muffler, so a clogged cat can't be an issue. Sorry if speaking of this is against forum rules, I am simply mentioning it to eliminate that as a potential issue...