Have a guy i work with with a 95 zj that had a bad motor (knocking) he bought a 4.0 out of a running/wrecked 99 XJ.

I can tell a few different things just by a quick look I took the other day.... he will have to use his 95 intake, coil, and distributer (harness plugs are different).
I also see a sensor on the back drivers side of cyl head on the 95 motor that the 99 does not have and has no plug even in the head for.
But, on his old engine, this sensor was not even plugged up.....

Can someone tell me what that sensor is and if there is anything else he will need to look for that will be different? Also use flywheel out of the 99, or swap the 95 flywheel on to the 99 motor? Ive searched and found nothing directly about the swap...thanks

 

sensor for the temp gauge maybe

 

look like this

 

thats it freegdr........ and his is possibly a 94 instead of 95 also. Hes from Guatemala and he no speak good english.