88mjblue

I found this piece of paper behind the tach, so I think I'm all set!

Interesting. Off topic, but I guess the light has a different look when bounced off either white or blue? Or is blue the raw plastic and then they died it white to get better lighting reflection? Different circuitry too on the 91+. The 90- looks very similar to the instrument cluster on my chevy squarebody - has the same gauge mounts, same bulbs and bulb holders, and even the exact same 18-pin electrical connector and similar style circuit board: And here's the Jeep cluster for comparison: Does not surprise me though, I've seen a few other shared GM stuff in the AMC jeeps: same seatbelts, HVAC control, steering column, MAP sensor (to name a few)

Thanks for the info Eagle! I didn't know that about the speedo cable, thanks for letting me know. Is it a different style connector at the rear? Same at T case I'm guessing? I need a new speedo cable anyways, but I might stick to my old speedo and 88-style cable since the mileage is accurate and the trip odometer on the new one doesn't work. Side note: seems like all trip odometers are broke, is there a way to fix it? I took the speedo apart and tried lubing it, that made it slightly better, but it still skips and doesn't reset to zero properly.

Don, it's a white case, but has a blue film (see first pic) that the illumination lights shine through. Maybe they ditched the blue plastic film and just colored them blue later on? The 84 I got this from looked like one of the very first XJs ever made.

Not a HO cluster, came off an 84, I saw dates and pieces of paper inside the cluster from the factory stamped with '84. I don't have the black bezel that came off it, maybe that's throwing you. Here's what it looked like more complete with black trim:

I found a "full gauges" cluster with tach to replace my idiot lights: Looks good, but now I am wondering if there's going to be a compatibility issue with the tach. I have the straight-6 242ci in mine, but the donor (1984 XJ) had the GM V6 I believe. Will this be an issue with getting a proper tach reading? It could have had the 2.5L, again I can't remember what engine it had... Can you tell by the rpm range? Was the 4 cylinder also available with a tach package?

Or, if you do plan to re-gear to 4.10's, then just drive slower on the highway to keep the rpms down, and in turn you'll get good mileage around town driving normally.

Are you sure you really need a new ring and pinion setup? Sometimes it's just the bearings that are shot and you can reuse your ring and pinion gears, but if those are truly in need of replacement, then I say why not, it will have a bit more "kick" driving around town...

Thanks for reminding me, still going around leaking water here... After NOS, is an aftermarket heater core made of copper the next best thing? I found a copper one on ebay for $56 shipped, seems reasonable to me.

Jon (aka 5-90) was working on a prototype replacement for this very part, but not sure he has it made up yet. The whole power steering assembly has to come out to change this, so I would find one from a junkyard and swap it out. Here's an excerpt from his website: On the earlier XJ/MJ with 4.0, the belt is tensioned by a long bolt underneath the power steering pump. OK so far. This bolt has a knuckle on it - this knuckle has two holes. One is threaded to be borne by the bolt, the other is smooth and has a stud on the bottom of the pump housing on it. Still fine. When you tighten the belt, all of the strain is borne upon the threads in this knuckle - about a half-inch of threads about 1/18" deep. Small problem. This knuckle is made of "sintered" metal - metal that started life as a powder, was poured into a die, and heated and pressed to make a solid part. Problem! While sintering (now called "powder metallurgy") has made remarkable advances in strength, these knuckles were made before the advances. I've broken three of them so far. Considering the entire power steering pump has to be removed to replace the thing, we think it's worthwhile to make something that won't have to be replaced so much... Again, these parts are CNC machined from wrought bar stock, and the solid threads will hold up nicely to the strain of holding belt tension before you can torque down the rest of the pump bolts.

Head gasket was fine, I was just being over-precautious/worried... I guess cast iron block and head holds up well to a bit of heat. Engine runs great, plenty of power, no leaks/smoke or anything, it was just a dirty and old [see closed] cooling system. I flushed it out completely and saw what looked like mud come out of it when I hooked up the hose to backflush system and heater core.

I've seen this many times, it is very common and is a fault of the mj/xj design, or the strength of the metal as a whole/inadequate bracing/support. My 88 mj, 90 xj, 95 xj, and 88 xj all have this problem on the driver's side door as well as the passenger side. Two of them had the door check completely ripped through the door metal - nut still attached - (similar to yours judging by your picture) and the metal on the door where it bolts up to was mangled so a new one would not bolt up. I removed them to solve the rattling like you had, and I'm just careful when opening the door so it doesn't swing open too far which would put stress the door hinges directly (which the door check is meant to prevent). The other two xj's have the door check hanging on by one bolt, but don't work properly: not ratcheting and can't hold the weight of the door, so it swings free (but stops from stressing hinge fortunately). I guess a solution would be to fab a plate of some sort (or maybe even a wide washer might work) to reinforce that area where the check mounts up to so you could properly mount up a new one. At this point, I have just removed mine, and now the door operates smoothly, with no rattling when driving/closing, but it does not hold it's position - so it's like a yj/tj door... Let me know if you find a solution and can mount up a new one that will hold for years to come.

I'm going to be buying an '88 and the previous owner (who drove it about 900 miles from a neighboring state up to my state to sell it) said it overheated on him twice, so I wanted to test the engine before I pulled the trigger on this one and make sure the PO didn't damage/warp the head by overheating it. The first time it overheated, he stopped immediately and had it towed and then a shop replaced thermostat and pressure bottle. Then he drove it for a another couple hundred miles and then it overheated again... The cooling system is old and dirty, and I will be doing an open conversion, flush, replace radiator, new water pump, hoses, tstat -the whole nine yards- but wondering if he did any non-repairable damage to the block.

Is there a way to test a cooling system for a head gasket leak in a closed system? (with a pressure bottle, aka stock renix system) The tests I've seen use a radiator cap adapter and I'm wondering if there's another way to perform a test like this?

Agreed. If you want to put a "modern" engine in, then go with an LS (for all the reasons above). And the 3.6 will never come close to the legendary status of the AMC straight six. Someone tried to claim this earlier in this thread, but I'm not sure how/why/for what reasons they would say that? Sorry, but Chrysler products today are garbage.

Very excited for you! Congratulations! I think you'll be happy with it, and as others have said, a $1k MJ in that condition is definitely worth it, even without an engine! I had a similar problem getting the thermostat housing to seal properly. Had everything buttoned up after converting to open system and then it leaked out of the thermostat housing/gasket after I started it up. Trick is to get it centered and make sure the gasket doesn't shift when putting it on, and then torquing down the bolts evenly. And yes, overtorquing can crack the thermostat housing, which he managed to do! Funny about the water outlet - he must be a chevy guy, that's what they call thermostat housings. I was confused when I first heard someone call a tstat housing a "water outlet." They also say rocker arm cover instead of valve cover (which actually makes more sense if you think about it). Go through cruiser's renix tips and you'll fix that idle.

I think maybe you did something when you re-wired everything after taking it all out. I would double-check that you have the speaker wires from the amp to the speakers wired correctly to matching positive/negative terminals on both ends. And check the RCAs from the receiver to amp for the same. Did you label everything before you took it out? You said you had a powered sub? How do you have the wiring set up to power/ground for both sub and amp? Do you have x2 distribution blocks for ground/power split to both (i.e. common ground). If you unplug the sub's power/ground does it sound good playing from just amp + 4 speakers? Also, I don't think the issue is running the power and signal lines close to each other. The comanche cab is so short and this problem really only happens on longer stretches of cable runs. I have a fat 0 AWG cable running right next to RCAs and don't have any wine at all, and I'm using some basic mid-range nowhere near close to audiophile quality RCAs. Plus, like you said, it was sounding fine before with cables together. If possible I would still separate as a matter of course (not sure if you can, if your cables have the length to do so.) Small thing, and probably not it, but headunits usually have a menu option to turn off the internal amp (if not using an external one) and that can help eliminate some noise. Just a tip if you haven't done this, and this is probably not what's causing that wine, but will help with sound when you do get to the bottom of this! So frustrating that it worked perfectly fine before and now it's having problems after you did all that work! Did you remove the full dash and bedline the firewall too?

I just picked up a blue lens ash tray light from the junkyard from an 89 xj (also got the tweeters). Just wondering, how does the light turn on/off? Or is it always on?

How much should I expect to pay for one of these? My heater core started leaking at the beginning of winter, and I've been going all winter without heat! Luckily I have a HCV so coolant loss has been slow, but the heater core replacement is on my to do list for this summer. Where did you get those NOS cores? Part number? Or are you willing to part with one?

I thought that was just the junkyards I've been to in my area, but I also rarely see any TJ's in a junkyard. I've only seen a few and they were completely wrecked. Were there just not that many made, or are they more of a collectible?

Idle solved!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! After over a year of tinkering (and giving up) I have finally solved my low idle! (I never thought this day would come :banana: ) By using the feeler gauge method as described by dkmcgowen here, I was able to dial in my idle. I found that for my 88 MJ, I got a smooth idle exactly at the 750 rpm tach gauge mark by going with 0.003" (+/- 0.0005) using the same method in the video above. So Mcgowan, like the other 2 comanches you sampled, mine too likes it a bit tighter than what you found on yours. And mine also has the air bleed valve completely closed. Cruiser54, I think you should update your Renix tip on the butterfly adjustment procedure to include using a feeler gauge to get the adjustment exact (or close). I followed your tip exactly when I first made the adjustment (and subsequent adjustments/cleanings) with the throttle body removed, and stopped at just the first movement of the butterfly valve as described – it turns out this was too closed (and no, it was not digging into the throttle body at this point). By opening it up just a hair (to 0.0035") this made a huge difference and solve my low idle. TPS at 17% (confirmed through MT2500), This tiny adjustment was the trick, this was not Uncle Bob stepping in: the IAC still functions. In the end, I probably made some unnecessary repairs/part replacements, but it was worth it in my opinion. Just as an FYI, here's everything I did prior to solving my idle: (some may have helped along the way, I will never know......) - full kelley's WiP cable mains upgrade (plus additional fender ground and ground strap replacement) - C101 eliminated + sensor grounds soldered - Throttle body removal, cleaning, new gasket - IAC (replaced, but was unnecessary) - MAP (replaced, but was unnecessary) - CTS and pigtail replaced - Vacuum harness front/rear new - CCV tubes and grommets new - tested all sensor wires for continuity back to ECU - O2 sensor wires tested for heater voltage, ground, ecu - tested harness resistance - new exhaust manifold and intake/exhaust gasket, torqued to spec - 746 injectors - 1989 ECU - passed fuel pressure test (31, 39) - CPS tested (6 AC Volts) - new fuel filter - removed and cleaned MAT - distributor indexed - EGR valve new (confirmed working with MT2500) And probably some more stuff that may/may not have helped. Thanks again everybody who helped me along the way, especially dkmcgowen for that last step.

Thanks so much for taking the time to write everything out, detailing all the work you did, and for making those videos. I will be trying to replicate your butterfly stop screw and air bleed screw adjustment procedures to hopefully solve my low idle. I have the same exact numbers/symptoms as you did, and have done (almost) everything you have done to try and solve it along the way. My experiences with the O2: I too have been having trouble with the NTK sensor, and will start checking dealerships/ebay for an OEM sensor. I have the MT2500 scanner as well, and observed O2 sensor Voltage was switching slowly, sometimes not at all.

Found a good deal on a MT2500 on eBay for $70, got adapter for $10 and cartridge for $30. I cancelled my repair shop appointment, hopefully I can solve this myself! I will report back once it arrives and I can plug it in and see what's up. In the meantime, I did some more troubleshooting on the idle thing. I found out that unplugging the IAC at 750 rpm keeps the idle right there - a short term solution for my idle problem. Does this help pinpoint my problem? Or eliminate any other sensors/things? (As a recap, I have previously replaced the IAC with a new one, and no change)

I checked out some used MT25000's on eBay, and for just a little bit more than what I will have to pay to have a mechanic use their fancy newer snap-on computer station I could buy my own. Does anybody own one of these, and know which adapter cable and/or cartridge to get?

Well, I've just about given up here trying to solve this low idle problem. I have scheduled an appointment with a mechanic (gasp!) to take a look and get another opinion. They have a Snap-On tool with the Jeep/Eagle diagnostic connector and I am hoping that viewing some live data will shed some light onto what's happening when the idle drops. Has anybody done this before? I know some people have gotten the old Snap-on MT-2500 (aka "the brick"). What should I be looking for, and what exactly can be read from this primitive Renix computer?