Older 2.5L, 4spd; '97+ dash. Incompatibilities?

[countryjeep]

Right now, I've got a bunch of things going on in my life that will not permit me to get to work on my Comanche, nor do I have a '97+ donor yet (or the money to be looking for one :cry: ). But I would like to know a few things...

 

Being that my Comanche is in-between '86 and '87 ('86 components; '87 short-bed, documentation, owners manual), I can't tell if the 2.5L it has is the 117hp or the updated 121hp. I have confirmed that it has a AX4 and not a T-4 tranny, so I'm beginning to think that the motor might be the newer 121hp?

 

But to the point... is there any way, provided I have all of the wiring, electronics, etc. to adapt my older style motor and tranny to the newer style dash? I already see obvious issues I might encounter, such as having the right sensor for the speedometer (in my case, the AX4 has a cable instead of an electronic sensor; I'll assume the tranny has to go), OBDII adaption (I couldn't swap the ECU from a newer 4.0L to an older 2.5L, of course), etc...

 

I REQUIRE that it has a 2.5L and 4-or-5-speed tranny of some sort in the end at least, due to gas issues (my ZJ gets 13mpg, the XJ gets 17mpg; I hear the 2.5L's get 25mpg). I've found a few good donor 97+ Cherokee's with 2.5L's and 5-speeds, but they're good shape 2-doors, and I don't want to take a rarer Cherokee off the road if it's still in good shape.

 

What will work? I don't want to know what won't work; if any one thing wouldn't work, I'll look for a full donor. I want to have all of the features of the '97+ dash, components, computer, air bags, etc. and if any of the original parts that are still in the Comanche would prevent any of the new components from working, I'll wait for the right donor.

[JeepcoMJ]

well, you CAN put a np231 transfer case onto the ax4/ax5 i believe. and were it out of a newer cherokee with a speed sensor rather than a cable, you could then just put the newer speed sensor in it.

 

the sensors in the 97 plus for the engine would have to be used (sorry, not sensors, sending units is what i meant). so temp. and oil pressure sending unit would be needed.

 

but Yes! you could make it work. and you would have to use the newer engine harness as well then. so basically you're best off finding a complete 97+ xj with a bad motor (or good motor to swap into yours) and swap all the components. you'd need the newer heaterbox and it's ductwork as well. also, I believe that some of the mounts changed for the dash as well, no big deal though. also you would need the newer style doors if you intend to have nice newer style door panels...

 

it's a big project, but well worth it in my opinion.

[countryjeep]

well, you CAN put a np231 transfer case onto the ax4/ax5 i believe. and were it out of a newer cherokee with a speed sensor rather than a cable, you could then just put the newer speed sensor in it.

 

the sensors in the 97 plus for the engine would have to be used (sorry, not sensors, sending units is what i meant). so temp. and oil pressure sending unit would be needed.

 

but Yes! you could make it work. and you would have to use the newer engine harness as well then. so basically you're best off finding a complete 97+ xj with a bad motor (or good motor to swap into yours) and swap all the components. you'd need the newer heaterbox and it's ductwork as well. also, I believe that some of the mounts changed for the dash as well, no big deal though. also you would need the newer style doors if you intend to have nice newer style door panels...

 

it's a big project, but well worth it in my opinion.

 

Good to hear! Right now, it has a blown head-gasket closer in towards the water jacket, because it's spewing water out of the rear of the block, but it's not seeping into the oil. Other than that, it runs great and sounds great. Clutch is also completely gone, but all gears seem to be ok (yes, I got it going fast enough downhill to try 4th gear. :D ).

 

I'll be going the whole way with my Comanche. Meaning new front clip, new dash, new doors and door panels (with 2-door '97+ XJ power window switches, if any were ever made), new seats (may possibly fabricate a decent bench seat), new console (may build a short hybrid if I go with a bench seat), properly painted interior trim that cannot be replaced (such as the rear speaker/seat-belt/rear-window trim), a '97 or newer DCX color, and special-made Comanche labels for the doors in the same font as the '97+ Cherokee's (labels, not paint, to go along with originality). The only thing that will stay the same is the brake light assemblies, though I will get some new ones as mine are broken :roll: . The camper cover will also be removed.

 

I do hope to keep a/the 2.5L, and I wouldn't mind going from a 4-speed to a 5-speed to eliminate the speed sensor problem. Or it would also be AWESOME to go 4WD with it, just some extra work. All in all, I'd like to have what would have been a base-model 1997 Jeep Comanche by June of 2008, when I graduate from high school.

[Eagle]

Obviously, the new style dash will bolt into the truck. The problem you face is that in 1991 Chrysler reversed polarity on all the instrumentation, so to swap in the new dash you would also need to change a bunch of sensors AND swap out the body harness -- while maintaing the original ignition/injection harness. Your other option would be to find a late model 4-cylinder XJ with the multi-port injection and swap in the newer ECU and injection along with the dash and body harness. That should get you more horses and equal or better fuel economy.

[Crash_AF]

It'll be a little harder than that, the instruments in the 97+ use the Chrysler Collision Bus to communicate so you'd have to find a donor 2.5L 5 Speed and gut it of all wiring (and I'd just swap motors while you're at it) to make the dash work.

 

The non technical way to say it is that the instrument cluster is a computer that talks to the engine computer.

 

There were 2 door 97+ XJ's made, I used to own one, but the 97+ panels would have to be combined to get the 2 door switches into the 4 door panel because the face plate for the panel is permanently attached to the door panel area. Not impossible to remove, but it's not a PnP job.

 

Later,

Joe