99 Engine in 88 XJ

I'm in need of a new engine for my 88 XJ. Mine it totally stock, but the engine is shot. It has blowby, no power, has been overheated and otherwise abused. I found a 99 XJ that has been wrecked and is being parted out. The guy said the engine runs good. I'm looking for advice.

Will a 99 engine fit a 88 XJ? What all do I need to get to make it work?

How can you tell if an engine is good or not in a wrecked XJ?

Oh and what's the going price for a part out motor?

Wow. Nothing. Come on guys, I could use some advice.

I'll give some general OPINIONS, since I'm not specifically experienced with the '99 XJ, but have done more than one engine conversion in my time.

First, I'd put the probability of fit at 95%, as long as you accept the need for minor engine compartment mods to accommodate the slight differences between the engines/years. Making it fit will be the least of your problems.

Second, you will want every scrap of wire, harness, and all applicable plugs/jacks from the '99, including the under dash harness and all gauges. Make sure you get the PCM and the the VSS from the '99; it's all different than the '88 RENIX-based (yours) fuel injection systems.

It may seem like an over kill to take so much of the '99's wiring, but it's better to have it all to start with, than 4-months down the road becoming aware that you need a particular jack, and having to scour JY's to find it!

Good luck, the project will be rewarding.

I believe the 99 engine will fit fine assuming you are swapping a 4.0L for a 4.0L. You either have to use your 88 intake and exhaust manifolds, fuel rail and injectors, sensors and distributor OR swap everything from the 99 including the computer, transmission and tcc, wireing harness, gages, all sensors. There are several write ups about engine swaps. As far as is the engine good? How many miles, was it well maintained? Can it be started or turned over? I have read about folks getting good engines for around $400.

A 1999 engine block should fit in an 1988 Cherokee. Use your Google-fu to confirm. Re-use and re-install the 1988 intake and exhaust manifolds, flywheel, distributor, and engine sensors as needed onto the 99 engine block.

Swapping the complete 1996+ OBD-II systems and ECU is possibly, but will require many, many extra hours of labor to remove and swap the complete engine bay, transmission, and dashboard wire harnesses and the dashboard itself from 2 Cherokees. And if you forget any little wire harness, wire connector, sensor, or bracket you will need to scrounge that up after the donor Cherokee is long gone.

A good junkyard will give you a 90 warranty on your used engine and the best yards offer optional warranties on used engines. If the yard will allow it, you would want to have a look under the valve cover and inside the oil pan. Prices vary, and you can always watch on CraigsList for complete running junkers.