have some tech questions

[XJFever]

hey ok, so I found a potential buyer for the 4.0 I6 HO out of my wifes old jeep, however he wants it for his 1989 wrangler, I know he would need the computer to also run it, and I am guessing some modification to get it mounted inside...but he's kinda iffy about having to do too much to get it working...anyone know exactly what would need to be done? I want this thing gone, and in good conscience I cant just sell it and saying "it will just work"/

[jps4jeep]

yes, he will need the ecm and all the sensors that go with the motor. Motor mounts from a 4.2-4.0 I believe are identical, someone else might now better. there is no easy way to put that motor into an older jeep, can be done, been done plenty of times, Kent did it in his CJ last year, he would be able to better explain the details.

[mika401]

It would be a lot easier if he had the complete wiring to go along with it.

[Bradman]

It would be a lot easier if he had the complete wiring to go along with it.

x2


I know there were some differences in the wireing harness and a few of the sensors with the cherokee engine we are installing in Jays 97 TJ.  Not sure if they are the same in a YJ but I think there were 2 different in the TJ.  It is always easier to use the original wiring and you won't need it for anything so sell it with the engine along with all the electrical components

[XJFever]

I agree, I want to sell him the motor with everything he will need, but he and his father seem to not have any ideas on doing the swap, and they are contemplating at this point if they want to do the swap if it requires too much work(he mainly needs the motor because the old one is totally seized up), so lets see what they say when I give them the heads up about it.

[mika401]

Almost every year 4.0 wiring harness is different, at least with the YJ 91-95 makes swapping a real pain

[jeeptech]

Does he want to inject it or run it with the carb?  The carb intake from the YJ will bolt to the 4.0 with some work.  The 4.0 ports are all in line unlike the 4.2 which has staggered ports. You need to do some grinding and fitting and use a different exhaust manifold than the cast 4.2. I think the P/S pump needs some mods on the bracket, Can't remember.