swapping newer 4.0

[Andrew T]

I have a 93 XJ, 4.0, AW4, and 231. I have new axles and a new t-case, but the engine and tranny both have about 165,000 miles, and I'm really noticing a power loss. My idea is to swap in a newer 4.0L and auto tranny from the newer body-style. Has anyone done this? What differences are there as far as the ECU is concerned? I know that mine has a distributor and the newer ones have it "built in" on the camshaft (I think), but how does this affect the swap? Basically, is there anything special I need to watch for when getting a drivetrain? I just don't want to spend $$$ then have it not work right....

Thanks in advance...

Andrew

[Eagle]

165,000 miles is nothing on a 4.0L unless it was really abused. Before dumping a lot of money on a replacement engine, I'd start looking at simple things that could reduce power -- such as a clogged catalytic converter, dirty injectors, dirty fuel filter -- simple stuff that is often overlooked.

[Andrew T]

Assuming that the engine has been used, but not necessarily abused, simple stuff like that will make that much of a difference? I know that those thing all help, but I just don't see them doing that much. But, as you said, a newer engine swap would be a lot of $$$, so I guess it wouldn't hurt to try...

Andrew

[M. Lake]

If you need to replace the cat, then the O2 is most likely on its last leg. The parts listed above, as well as the O2, can produce a bit of lag that would be noticable in the time-2-rev. Builds up slower. If you want to go with the newer block, get around a '97-99 with the different ignition system. The 7120 heads on the older blocks are better and the 99 and up wj 4.0 intake manifold has a bit longer sweap on the runners and would give more umph. If you have the ABS, it would have to be removed to fit the intake. http://www.angelfire.com/my/fan/IAT_sensor.html Adjustable MAP Sensor

[M. Lake]

http://www.madxj.com/ Adjustable MAP Sensor