WesD

General rule 10psi per 1000 rpm. You're OK.

Oil in the air filter is a sign of blowby (oil being pushed past the pistons, picked up by the PCV valve or crankcase breather, and dumped in the air filter. You can drive it like that for a long time but it will only get worse with time, until you do a rebuild and get new piston rings.

I'd look for a wiring diagram of the 99, and compare it to a wiring diagram of the 89. I'd be surprised if there's a lot of difference in the rear wiring systems. Once you get the wires straightened out, I'd remove the connector right at the tailgate and splice it into the new harness so you can remove it again without cutting wires. Off-topic, does your removed 2.5 have the ac compressor bracket? I'm looking for one.

I've done this swap in a Chevy K10 before (it was pretty easy) - I'm hoping that GM and AMC/Jeep used similar design methodology where every system was a separate sub-system, which makes it easy to piece in the subsystems ad-hoc. (Cruise, A/C, power windows, locks, etc would all be considered sub-systems). I also recall seeing these complete systems for sale in JC Whitney for around $999. Sure wish I had the kit today.

(I read the AC writeup below - it was helpful) I am adding A/C to my 87 2.5. The local J/Y has a 91 XJ with a complete system, so I have a couple questions: 1. Will the evaporator housing from the 91 work in my 87 without mods? 2. Will I need to replace the underdash wiring harness, or will the existing one work? 3. Is there anyone offering a compressor bracket for the 2.5L? 4. Will Renix vs. Non-renix make this a difficult swap? I have done this exact swap before on Chevy full size trucks so it's actually pretty easy if I can figure out the answers to my questions above.

Excellent, please let me know if you do. I'll send you an I'm with my phone number.

Pete, which J/Y is that?

And she's alive: Replaced the fuel pump. This was a pain, as the Walbo (Denso) pump I purchased (Made in USA) was too short to fit correctly. Four different parts stores later, and O'Reilly had one that looked the closest. But now, the strainer sock didn't fit tight on the nipple. I ended up using some glue to hold it on there and it should be good now that it's back in the tank. I also discovered a hole in the tank on the top, so it will be getting replaced. Anyways ran a ground wire to the unibody, 10 seconds of cranking later and it fired up and ran great. Hasn't run since 2002. I did replace the plugs, wires, fuel filter, fuel pump, and battery before attempting start, but that's all.

Very nice work.

Updated post #2 with pics. The rest of the pictures will be inserted sequentially in this thread.

89, I don't see any need. Nothing wrong (known) with the engine. Just needs to be cleaned up and fired up. If there was a problem, I'd go with a 4.0 instead of another 2.5. I've done engine swaps and full rewire jobs on some other projects so that doesn't scare me at all.

Appreciate the thoughts guys, I'm in Florida. Hoping to keep the parts search in the southeast.

NEXT: Start collecting parts! Need a long bed, preferably southeast US. HELP! Do you see a Comanche in here? How about now? A pressure washer and she cleaned up pretty nice. Got the bed pulled, it was easy. Removed and drained gas tank. Gas wouldn't even burn. The pump is toast, very likely the sending unit as well. Loaded up and ready to go. Very likely the only GMC Yukon Denali ever used to tow a old truck out of the woods. Parked at home.

This is dedicated the restoration/rebuild of my dad's 1987 Jeep Comanche. He bought it new in May 1988, it's a base long bed 4x4, 2.5, 5 Spd. I still remember going on the test drive with him. I learned to drive in this truck, drove it through high school and college, and it was rear-ended in an accident in 1999 which took it off the road with just 109,000 miles. The bed was destroyed, but the rear subframe appears undamaged and it was drive able. It was last driven in fall 2002 and hasn't been ran or moved since then. Over the years various parties have inquired about taking possession of the truck, and just recently my dad mentioned to me that I can come get it. So those plans are in motion. My goal: To make this thing look the way it did the first time I saw it in May 1988. Meanwhile, I've taken stock of where it sits and what it needs: 1. A new long bed, rear bumper, and tail lights. 2. Drivers side floor pan. 3. A full AC system (this is a non-AC truck and there was lots of complaints about that in the past). Any thoughts on where I can acquire these parts are much appreciated! This thread will be the documentation of the build and hope to share the experience with others. And I want my dad to drive it again. The old pic is from sometime around 1990, and the other pics are recent condition.