Eagle

No. It might be the temperature sensor. Not the one in the head that tells your dashboard gauge how hot the engine is -- I'm talking about the one on the left side of the block that tells the ECU how hot the engine is. When the Renix starts up, until the engine reaches operating temperature (around 165 to 170 degrees) it ignores sensors such as the oxygen sensor and runs on a pre-mapped, extra rich fuel curve. Once the temp comes up, it switches out of "open loop" mode into "closed loop" mode, in which it responds to sensor input. My guess is that, if your temp sensor is bad (or, God forbid, your ECU), you are stuck in warm-up mode and running too rich. That extra rich fuel curve could be too much for the engine to handle at warm idle.

Our phone and electric lines came down in that freak early-winter storm that hit Connecticut a week and a half ago. Everything went dead Saturday evening. The power company did very well, and had us back in service late Wednesday night (and we were among the last, since the problem was the wires from the street to the house. AT&T, however, was not nearly as helpful. I reported the outage the day after the storm, which was a Sunday. They promised we'd be repaired by Friday, November 4th, by 8:00 p.m. Later in the week I called again to see if there might be an updated prediction. Not only was there no update -- there was also no repair request on record. So I entered a new trouble report (two, actually, one for each land line). The new repair promise was now Monday, November 7th. Monday came and went, but no AT&T. So on Tuesday I called again, from work. And, once again, there was NO trouble report on file. I hung up on the automated repair system, called back, and waited without touching any buttons until the system defaulted to letting me speak with a live person. She told me the previous trouble report had been cleared because a technician had checked the line and it was in service. I not-too-politely told her that was impossible, because the wires had been ripped off the side of the house and were lying on the ground. I told her I didn't appreciate being lied to, and I requested that she enter a new report and specify that the wires were down. And then I called the state agency that regulates public utility companies and I filed a complaint with them. Dang, I hate AT&T.

I haven't tried it yet, but you should be able to drop the rear by replacing the second and third spring leaves with the flatter leaves out of an XJ spring pack. Or cut the XJ main leaf to the same length as the MJ second leaf and go from there. Dunno if he's still lurking around here but "Andy in PA" had a lowered 2WD MJ a few years back. Be careful in the front -- if you get too much drop the oil pan is an interference fit on the front axle.

AFAIK the only parts that are different are the output shaft and the tailshaft housing.

If he has a 242 transfer case, there is no disconnect, and the front drive shaft does turn all the time. It just isn't always connected to the engine. Unless he's running the 242 with the original MJ front axle. In which case, that would be a problem, because the 242 in full-time mode won't make the vehicle move if the front axle isn't connected. If it is the original axle, I would shim the disconnect so it's always engaged, then see if the grinding noise is still present. The disconnect is actuated by vacuum, and the 242 doesn't have a vacuum port.

I thought the same thing until my dad explained to me that if the OD of the muffler is 2.25", and the OD of the pipe is 2.25" they won't fit into each other. But muffler sizes are not specified by the OD of the muffler tube, they are specified by the OD of the exhaust pipe that fits in it. In other words, a 2-1/4" muffler is made to accept 2-1/4" pipes. It does not mean that the OD of the muffler inlet and outlet are 2-1/4", it means that the ID is 2-1/4".

If they sell a 2.25" and the pipes are 2.25" why do you need an adapter?

Right.

Live with it. It's a peculiarity of the Renix system. The dealers even had a name for it: "Early morning drive-off stall." My '88 XJ has always done this, and I bought it new. A couple of years after I bought it, my dealer had retired and sold the business to a pair of crooks, so I switched to another Jeep dealer for service. The service manager there talked me into having the C101 connector (which your '90 doesn't have) bypassed. He promised me it would improve starting, improve gas mileage, cause beautiful women to throw themselves at me -- and cure "early morning drive-off stall." The work was covered by a TSB but, unlike a recall notice, the customer pays for TSB work. IIRC, it cost me $500 -- and that was back when $500 was worth something. Naturally, it didn't fix any of the things he had claimed it would, and when I confronted him later he absolutely denied having told me any of what I remembered. Needless to say, I no longer go to that dealer for service. The point of all that being ... you are not alone in having that issue and, if you have it, just live with it because there isn't any living person who really REALLY knows either what causes it or how to fix it.

If it only overheats at idle but not when rolling down the road, the thermostat isn't stuck closed. More likely the viscous fan clutch isn't spinning the primary fan fast enough. They do get tired. Overheating at idle is the classic symptom.

I bought my '88 XJ new in January of 1988. The original starter lasted until about 1997 -- call it ten years. I replaced it with one from AutoZone, which I had to replace about a year ago. IMHO, go to any of the parts chains and buy their premium starter. It'll have a lifetime warranty.

Looks good from here. Disclaimer: To be candidly blunt, I still think putting an XJ proportioning valve into an MJ is about the dumbest thing you can do, but that's only because I've been driving my old XJ without any rear brakes for two or three years due to the bloody proportioning valve clogging up and me not having time to take it apart and deactivate the O-ring and plunger. Once I do that, it'll be just like an MJ distribution block -- no proportioning function at all, but at least I'll have rear brakes. I can deal with too much rear brakes a lot better than I can deal with NO rear brakes. Just to repeat myself, if using an XJ proportioning valve is such a great idea, why do so many XJ owners take the O-ring and spring out of it?

Are you referring to the plastic speedo gear that you push onto the end of the cable and then into the tailshaft housing, or are you saying that the steel (or brass?) drive gear inside the transfer case is trashed?

IMHO, friends don't let friends buy Rusty's springs (or much of anything else).

If you use a remote starter switch, you can activate the starter without turning on the ignition, and you won't need a helper to turn the key. If you don't already have a remote starter switch or two ... you should.

:agree: Yep ... what he said.

There was no box behind or around the factory speakers in an '87 MJ (or XJ).

There's a possibility it's a crack in the flex plate, if it's an automatic. Test: Start engine. Rev it up and down a few times in neutral (not to redline, just up and down slowly from idle to maybe 1500 or 2000 RPM. Listen for a knock. If there's a knock, step on the brake, put it in gear, and apply just a little bit of throttle (just enough that the engine is pushing SLIGHTLY against the brakes). If the noise disappears, it's probably a cracked flex plate.

You probably read that in one of my posts -- that's what I did. Nope. Unless you had a front brake failure and the rear bypass got actuated, that circuit should not be under pressure. There is fluid in that line IF the proper bleeding method was used, so what's in the line will dribble out -- but it won't drain the MC.

Unfortunately, then you're on your own because we can't tell from wherever we sit if the speedo wire was even moved over to your truck. You need to find an XJ or MJ from about the same year, crawl underneath, and find out what color wire you're looking for and where it's supposed to go into the chassis harness.

Which is why there's a knock sensor ...

No.

A 1990 does not have a "Check Engine" light. You have a "Maintenance Required" light, which is just a reminder to replace the oxygen sensor.

You do NOT have to remove it to block the lower front outlet port. Just unscrew the old tubing nut and screw in a plug. Done.