1994 engine in a 2001 XJ

[XJWheelie]

I completely destroyed my 1994 XJ, but the engine (4.0 liter), transmission (automatic) and transfer case (231) are all in great shape. What I'd like to do is pull them and save them for when my 2001 eventually dies.

So is this engine, transmission and t-case interchangeable between the years? What about the computers?

 

[Talyn]

Computers won't swap. Use the sensors from the 2000 on the 94 engine. Use the 2000 throttle body. I would also use the intake manifold form the 2000 on the 94. Also, you will need to do something about the stock 2000 headers on the 94 head as they don't line up with the ports that well.

 

[XJWheelie]

The 1994 engine has an Borla header. The stock one cracked years ago, which seems to not be a problem in the newer engines. Also, the 1994 has a Random Technology catalytic converter and a Flow Master muffler. Do the exhaust systems line up from 1994 to a 2001 or did that change as well?

Out of curiousity, what's the difference in the throttle body?

From the sound of it the long block engine is the same then, but everything that attaches to it is different; correct?

 

[Talyn]

The head on the 94 is different. Some bolt pattern, different ports. The MAP sensor on the 2000 is mounted to the throttle body.

 

[ehall]

From the sound of it the long block engine is the same then, but everything that attaches to it is different; correct?

Not everything but there were a lot of changes big and small

Keep the computer in place since it talks to the whole car (dashboard, fuel pump, and engine too). Put the sensors that match the computer in the engine, and the computer will be happy with the engine. You also need to install the matched fuel injectors since they changed a few times too, and the computer will expect them to deliver fuel at the rate it was programmed for. Ignition and electrical parts were all changed between 94-01 as well--the distributor was replaced by coil-packs and a standalone cam sensor--so that all has to be swapped for the computer to still be able to control ignition. Even the connector on the alternator was changed, so you will probably want to swap that over too.

There are also a handful of mechanical changes. Talyn already told you about the intake manifold, which should be kept. Also the power steering pump and tensioner bracket assembly was changed in 96, and that stuff all bolts to the intake manifold differently too, so you will need to swap the power steering pump and bracket if you swap the intake manifold. If you have emissions inspection then you will probably need to keep the 01 exhaust manifold for the pre-cats and all that stuff... although I am not 100% on any of that stuff

The A/C setup changed too but if you can keep all of that intact on the 01 body

Yeah pretty much everything

 

[Tim_MN]

Install the Intake/Exhaust, ignition, head, all belt driven accessories, and flywheel from the 01 onto any 1991-1999 XJ or 1993-98 ZJ engine block.

1994 is OBD-I and 1997+ is OBD-II. Their sensors and throttle bodies mostly do not interchange.

This thread covers AW-4 transmission swaps - http://www.naxja.org/forum/showthread.php?t=1053970

The 94 T-case may not have the proper speedometer output for OBD-II.

 

[XJWheelie]

Well hell, now you have me wondering if it's even worth keeping the engine, transmission, t-case combo or not. I might be better off just selling them and if my 2001 ever dies either re-build it or buy a new engine.

You guys are giving me tons of great information, but you're definitely taking the fun out of my idea!

 

[kf_chris]

build a stroker. seriously. you won't regret it. Wait and take your time then put it in. I have a 2000 block with a 95 head in mine.
No harm keeping the parts if you have the space. Free replacement parts are nice.