'88 Jeep Comanche (MJ)

I sold my XJ back around May, and I had been looking for an MJ before I ended up getting my XJ. So before I put more money into the XJ I felt it was best to move on. Well after all that time I ended up hauling a truck back today with a friend. We drove about 2 hours out for me to get this one, it's a 1988 4.0L, 5 speed, D30/D35, Sportruck with 94,453 miles. The previous owner parked it roughly 10 years ago due to a bad alternator, he said about 6 months later when he went to replace it he noticed some of the engine harness had been chewed up and shut the hood. After intending to fix this up for his now 13 year old to drive he decided to sell it to help with bills and let it stop 'rotting.' It's in great shape, there are very few dents or dings and NO rust from what I've found. I can't WAIT to get this back on the road and ready to enjoy!


It's amazing what a pressure washer will do.


I plan on tuning it up and flushing all the fluids this weekend. I'll be scouring the junkyard for a renix 4.0/5speed engine harness to probably just swap it completely out.


  • TerminusVoxTerminusVox Senior Wagonist
    Damn a mouse!
  • RevmaynardRevmaynard Council Member
    Forreal! I'm considering repairing it this week and seeing how that fairs, that way if it works I don't have to source a new junkyard harness. Luckily one at the yard would only cost about $30. Got some tune up goodies today! :cool:
  • rbwdrivenrbwdriven Senior Wagonist
    I've always liked those trucks.
  • simplyhondasimplyhonda Council Member
    Looks like it washed up nice! Excited to see its progress.
  • CharbCharb Administrator
    Cant wait to see how this turns out!
  • RevmaynardRevmaynard Council Member
    Trust me, I can't wait to make progress! Dropped $300 on parts so far today...lol Ordered a new alternator that should be in Friday, went from a stock 65amp to a stock upgrade 105amp. Got all fluids for radiator, engine, diffs, trans, transfercase, and a bottle of Marvel Mystery Oil I plan on putting in the cylinders today to help lubricate them before I do an oil change this weekend. Got a water pump, thermostat, all heater/radiator hoses, all new ignition tune up parts, filters, and went ahead and got a new serpentine belt. I'm kind of bummed I don't get off until after dark or I'd get more done this week. I'm thinking of taking a half day on Friday since we're having our holiday party, that way I can tear out early and start working on it!
  • Nice score and man did it clean up nice. Back when Jeeps were built to do more than ferry spoiled kids around.
  • RevmaynardRevmaynard Council Member
    Yea it did! As soon as the first layer of shit came off I told my buddy the guy could have gotten another $1000 out of it. (but I wouldn't have owned it) lol First round of parts!


    I've never seen original '94-'96 lenses this clear.

  • RevmaynardRevmaynard Council Member
    The harness is almost wrapped up and done and ready to be put back in. I ordered a set of Chevy 1500 front brake hoses as they're ~6'' longer than stock, if my hoses need to be replaced before my lift I'll go ahead and use these. I also ordered a Spectra brand closed to open conversion radiator which should be here Friday. I'm going to pull the old one to get the harness routed back through the header panel area and figured it'd be the perfect time to convert. I started cleaning the interior just to see what it might take, I got the dash and panels pretty clean but the seat is going to take some work. I hope it comes pretty clean since the fabric is in good shape otherwise.


    After the harness, airbox, alternator, and a few other pieces were removed. I think at this point I had the grille and headlights out, too.


  • RevmaynardRevmaynard Council Member
    I received my open to closed ''conversion'' radiator. The Renix era Cherokee and Comanche (87-90) used a radiator with no cap, and had an pressurized overflow bottle. They tend to crack and generally make it a pain in the ass to burp the system so it's common that people go with a newer cap style radiator. The big problem here is that the newer cooling system uses a fan switch in the thermostat housing and the closed system uses one in the underside of the radiator by the lower hose which leaves you to find a solution to get the fan to run properly without having it on a manual switch. Well the one I purchased is essentially the same as the closed radiator except it comes with a cap, so a quick trip to the parts store or junkyard should net me a standard reservoir bottle to replace the pressure bottle with which will complete the ''conversion''. I also needed a shift knob and funny enough they use the same thread pitch as my Honda, however instead of throwing one of my spare knobs on I ordered a white Hurst ''poolball'' style knob. The harness is done and I pretty much have anything and everything to get this on the road other than some daylight and decent weather! It's either rained or been below freezing any day I've had to work on this, and I get home after dark so it makes that time pretty much useless.
  • ThaClutcHThaClutcH Senior Wagonist
    Can't wait to see this thing lifted.
  • RevmaynardRevmaynard Council Member
    I can't wait to lift it!

    Got my Hurst ''cue ball'' shift knob in the mail last night.....I guess you'd consider that progress....

  • RevmaynardRevmaynard Council Member
    Well my big hold up at this point is my harness. Everything else is practically done other than flushing the trans and diffs. The waterpump, thermostat, alternator, and belt are in. I've got the radiator in place but not installed as it's going to make fishing a harness back in a good deal easier. If I can find a harness this thing should be running with about 2 hours worth of work!



    I can't wait to drive this thing!
  • RevmaynardRevmaynard Council Member
    No luck on a replacement harness just yet, I've found a few RENIX era 4.0/5 speed harnesses but they all have additional relays and are routed differently.

    Buuuuuuuuuut, I did just make a sweet score. ;)

  • RevmaynardRevmaynard Council Member
    Made some headway on my old chewed up harness. I also got a clutch fork, seal kit, throwout bearing, and the CJ 304 pilot bushing for the ax15. Hopefully this harness will work out once I have it back in there. If that gets me on the road I plan to source the rest of the items for the ax15 swap, that'll be the first be project before a lift or axle swaps.


    The missing section was cut from an incorrect harness so the coloring would all appear as factory as possible.
  • RevmaynardRevmaynard Council Member
    Tomorrow SHOULD be eventful if nothing comes up....the last ''eventful'' day I was supposed to have ended up with strong winds blowing some shingles off of our roof so that had to be attended to before rain/snow. Assuming the harness is good to go after all the splicing/soldering I just need to do an oil change and plugs/wires (have them), and drain the tank. I'll probably run power to the pump and unhook the line and let itself pump itself into a tank so I don't have to drop it, but with that I expect to be running and on the road by Monday! Cross your fingers....! I ordered a few more parts for my trans swap like a bellhousing, fork pivot, and hardware set. I think I might try my hand at rebuilding it since I have access to all factory service manuals and diagrams and nothing needs to be pressed on/off, but I'm still in the air on that. I did kind of jump the gun and ordered a new usb/ipod deck, install kit with harness, and a pair of 5.25'' speakers so I have some tunes when I do have it driving!
  • RevmaynardRevmaynard Council Member
    The wiring is wrapped up, cooling stuff basically sorted out. I've just got to mount my universal overflow bottle now and fill it up. Next is sorting all of the vacuum lines that are chewed through and the old fuel.


  • ChaifeChaife Instagram grand master
    Lot's getting done here, cool to see. :encouragement:
  • RevmaynardRevmaynard Council Member
    I never really posted about it, but I got it to turn over off of fuel in the intake manifold after I got the harness back in. The pump is shot so I got a new one, just gotta take the time to replace it and hopefully this puppy will be on the road!

    Funny enough lilghosts fuel pump went out this week too, so it looks like my first time dropping a tank will be twice in once weekend. haha
  • ChaifeChaife Instagram grand master
    Revmaynard wrote: »
    I never really posted about it, but I got it to turn over off of fuel in the intake manifold after I got the harness back in. The pump is shot so I got a new one, just gotta take the time to replace it and hopefully this puppy will be on the road!

    Funny enough lilghosts fuel pump went out this week too, so it looks like my first time dropping a tank will be twice in once weekend. haha

    HAHA double up. Good luck with the pump swaps. :encouragement:
  • RevmaynardRevmaynard Council Member
    Thanks dude! I don't think Erin's pump will be here in time even with expediting shipping given all the shit weather lately though. Just so you guys don't think I'm BSin'! lol

  • ChaifeChaife Instagram grand master
    Revmaynard wrote: »
    Thanks dude! I don't think Erin's pump will be here in time even with expediting shipping given all the shit weather lately though. Just so you guys don't think I'm BSin'! lol


    Subscribed on Youtube and this thread.
  • RevmaynardRevmaynard Council Member
    Sweet! Thanks man!

    I got some cheap General Grabber AT2s from a friend for the time being but forgot to mention that. Today I managed to get the tank/pump out but ran into some fitment issues with the retainer on the sending unit fitting the pump, so after that got sorted and everything was together in the tank it was dark.




    Not juice....just old gas. It had just shy of 8 gallons in it.


    The pump I took out must have been a replacement because it was a Bosch. So in 94k miles this truck has had 3 fuel pumps. lol
  • ChaifeChaife Instagram grand master
    Ugh, That's some nasty shit. Looks exactly like what I drained out of that FC RX-7 that we're doing.... Damn low mileage barn finds.. :p
  • RevmaynardRevmaynard Council Member
    It's allliiiiive! Got the tank back in and hooked up today. Just went ahead and did plugs while I had my girlfriend run to the parts store for me. I shut it off because the fpr started leaking, so that'll get dealt with next. lol My clutch pedal is nonexistent so I'm hoping a bleed is all it will need for the time being.

  • RevmaynardRevmaynard Council Member
    Replaced the o-ring on the fuel pressure regulator and it took care of my fuel leak. After that I started it up and let it get to operating temperature for the first time in over a decade! I also used that as the chance to burp the cooling system. Soooo cloooose!
  • RevmaynardRevmaynard Council Member
    It liiiiivvvesssss! I thought the slave was shot, but the clutch was stuck to the flywheel! Just need to throw my decent tires on for now and check out the brakes before it's long haul worthy!

  • ChaifeChaife Instagram grand master
    Siiiiick, That's what it do. lol @ stuck clutch disc.
  • RevmaynardRevmaynard Council Member
    Yea man, when it would shift through gears smoothly off using the pedal and the fact I HAD a pedal I knew it wasn't the slave after bleeding it. I let that puppy get warm, revved the engine up a few times, threw it in first and started to pull away!
  • RevmaynardRevmaynard Council Member
    Bled the brakes somewhat. All of them bled well but the drivers rear. I could NOT get it to bleed properly. The pedal is still a little soft but it's a hell of a lot better than before. Got it rolling on a stock set of 97-01 XJ steelies for now until I get my other A/Ts mounted on the original wheels. I put about 20 city miles on it around the house (in my free tow zone :p) and went and washed it up a bit and used the pressure washer to get some more of the decals off.

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