ok for starters im a newbye to this form , and pretty new to the world of jeeps

ok so i have a 94 grand cherokee with the 4.0 (factory) auto trans with 231 xcase and with my luck it started knocking so picked up a 97 grand for the motor

what all differences are there in them? so far i noticed the 97 doesnt have a fuel return , so i know i will have to use the fuel rail off my old motor , also noticed the temp guage sending unit is not were it is on the 94 ( do i just have to drill and tap the head in the 97 ????)

also notice the throttle body on the 97 has a sensor on the right outer side but looks like the other hookups are the same on the backside like my 94 so can i just take the sensor off or do i need to use the throttle body off the 94 also???

last 2 questions i have is on the flywheel sensor will the one on the 97 plug into the 94 harness ?? and last question is my 94 has the 231 xcase in it and the 97 has the 242j in it , am i going to have any probs with swaping it into the 94? ( i plan on dropping in the engine trans and xcase out of the 97 into the 94)

I would greatly appreciate any help or info i will need to know before i pull old motor out and drop in the 97 unit so i can just drive it and enjoy my rig

Welcome to CF. The connectors were probably all changed over the years. You might have to install the '94s sensors into the '97 engine if the connectors don't work. JMO
The t-case swap shouldn't be an issue. You might have to swap speed sensors if the connectors are different.

The exhaust ports on the 97 cylinder head are different, but not a big deal. Use the throttle body from the 94 along with the flexplate and the rest of the sensors.

ok so dont try to drill and tap the head for the temp guage sending unit? ( sence the exhaust ports or different?) were would be my option to hook it up at? block drain port?

Can't you use the temp sensor location shown below, near the oil pan rail?

huh interesting i dont remember unhooking any wires from there on the 97 motor today but think there is a plug in the block there , funny thing is on the 94 it has that there but isnt hooked into the harness anywhere ( it has it in the back of the head next to the valve cover) so heck i will just extend the wires on the plug and hook it up to that port there , Thanks Ol Blue

No problem. As long as it works it all good.

when i bought my 94 the rednecks i got it from told me it had a 95 motor in it so my guess is they just used the 95 bottom end and put the 94 head on it cause there were alot of loose bolts on the motor that i had to tighten up

I wouldn't doubt it. I believe it should have 2 sensors anyway. 1 for the temp gauge, and 1 for the computer.

yea i have been researching all night and read that on the 97 and up they used a dual funtion sensor for the one in the thermostate for the computer and temp guage so best option for me is to just run it to the port above the oil pan

I would think that the '94 harness would have the 2 separate connectors for the different sensors. I may be wrong...

yes it has 2 separate plugs on the 94 for the sending units , thought about if i could splice the guage sending unit wires into the computer one to use the one the 97 motor has in the thermostat , but i doubt that will work so will just run it to the port instead

I don't know. The one for the comp controls the fuel injection system, the timing, as well as the cooling fan.

This should be a easy task... Yall makin it difficult... Lol... Just have at it... U got the skills to figure it out as u go... I can tell that already...

Research which transfercase u want though... They will both work with the linkage from the same vehicle they came from... They are very different but both will bolt up...

well went and looked at my 97 motor yesterday on my way to work and of course my block doesnt have a hole there above the oil pan , has the casting like there could be a hole thou , so idk if i want to drill and tap it or just hook up to the block drain port

would think they wouldnt of changed things around on these motors so much over just a few years but guess so lol