4.7 h.o. swap

Shadow32 · Nov 18, 2018

hi guys, long story short i crashed my wj with a 4.7 h.o and was thinking of fixing it but i thought buying a wj with non working engine might be cheaper. i have looked on the forum for some info but i couldnt find any (not really good a using the search). anyways my question is has anyone done a 4.7 to 4.7 ho swap to where 4.7 ho works exactly like in original wj? i have seen some info on knock sensors and pcm, but not sure if having all the original parts could help in not having to disconnect any of it. also does the year i purchase the replacement wj matter as i found a 2001 with non working 4.7. thanks for any help

97Mule · Nov 20, 2018

Why would it not work! As long u swap the engine harness and PCM, and all the small things that go with the HO.
The most important question is ....Do u have the time?

Shadow32 · Nov 20, 2018

thanks for the reply mule. i do have the time as this would be a project and dont need to finish it quickly eventhough i would like too, but i have read some post about knock sensors not working on a 4.7 setup because no wiring and also missing the wiring for two o2 sensors. im just wondering if thats the case up to where do i have to replace the wiring? would it be juat engine harness or would i have to replace wiring past the firewall?

97Mule · Nov 20, 2018

I would think that it would just involve the engine bay wiring, but if it needs more than that it will be easy to get at with the engine out of the way.

Shadow32 · Nov 20, 2018

thats kind of what i was hoping someone would know that way i can change it when it is off and not find out after i install new engine

97Mule · Nov 20, 2018

Just saying i cant think of a single reason why it cant be done.
I'm sure there have been a few on here that have done it, Wiring harness , PCM, Hyd fan .

Arjay · Nov 21, 2018

I have that engine in my Overland. Love it, great engine.

Shadow32 · Nov 21, 2018

yeah im sure its possible. thanks mule

mrvicio · Nov 23, 2018

I have swapped an HO in my 1999 wj limited. With my 1999 jeep I had to use the original wiring harness and PCM because the wiring harness of the HO is different and I could not swap it.
But if you try the swap with a "newer WJ" with the hydraulic fan (from 2001/02 and on), you don't have any problem as you swap the engine, the wiring harness, the pcm and the skim module (+ the key) under the steering

Shadow32 · Nov 24, 2018

that is what i was wondering mrvicio thank you. So the swap would be straight forward other than the wiring mrvicio? i am trying to swap an h.o. from a 2004 with the hydraulic fan into a 2001 with a non working 4.7

mrvicio · Nov 27, 2018

the swap is always straight forward but, if the 2001 has the hydraulic fan too, you can swap also the pcm, the wiring harness, the skim module, the keys and the muffler in order to get the full power of the HO, otherwise, youll'get a 4.7HO running almost like an ordinary 4.7

Shadow32 · Nov 28, 2018

what would be the issue with not being able to put the h.o pcm?

mrvicio · Nov 30, 2018

If you don't run the HO computer you won't be able to get all the hp of the HO. The HO computer has a different tune that let the engine gain hp. But in order to swap the HO computer you need also to swap the HO engine wiring harness... and you can do that if bothe the WJs have the hydraulic fan and the same amount of catalytic converters (federal emissions have 1 cat converter while california emissions have 3)

speedymopars · Nov 28, 2018

I swapped a 2002 ho into my 01 4.7, I did have to swap a few sensors over and the knock sensors are missing, but it runs great. I used the 01 computer.

Shadow32 · Nov 29, 2018

im trying to avoid taking all that off speedy since it takes away hp

Shadow32 · Nov 30, 2018

mr. vicio what if i swap engine harness,pcm,hydraulic fan with power steering box and exhaust from the h.o would that work or would the wiring not match up with the wiring to the pcm connector

mrvicio · Dec 3, 2018

this is an old topic I started https://www.jeepforum.com/forum/f310/4-7-4-7-ho-swap-4204210/

as you can read, there are also differences with the o2 sensors and the AC wiring.
however you can check on this website http://connectors.dcctools.com/home.htm if the wiring is the same or if there are differences.

My suggestion is to swap the HO engine and use the non-ho wiring and PCM.
If you want to get more HP, you can tune your non HO pcm with superchips flashpaq.

As you are going to swap the engine, you can consider also swaping your mechanical clutch fan with a better one from a ford explorer. You can find more on this tread https://www.jeepforum.com/forum/f310/1999-wj-fan-swap-3917042/index4.html
I swaped the clutch fan from a 1999 4.0L ford explorer. I don't know the ford codes for it but reading the thead i was able to see that the equivalent aftermarket parts are dorman 620-155 fan and hayden 2794 clutch

speedymopars · Dec 3, 2018

I picked up power from the ho engine installed in 2001 standard , though not as good as the full ho tuning, it doesn't ping and was easy. I swapped becuase I blew a head gasket and it was cheaper.

In your case, with the ho factory, not quite the same.

Shadow32 · Dec 5, 2018

thanks mrvicio that answers my question exactly i will be doing what you say and keeping the non ho pcm

Shadow32 · Dec 5, 2018

yes speedy i was hoping since i had the whole donor vehicle i would be able to without having to switch every single wiring

speedymopars · Jan 10, 2019

Hmm, I picked up quite a bit of power. I cant believe the tune is much different, in fact I wonder if it would have less timing to compensate for the additional compression. Or maybe it rolls the timing higher and waits for the knock sensors to pull it back. Dont know, but I do know there was a good increase in power with the 01 computer and no knock sensors. It pings occasionally with cheap gas (86) and high altitudes. I just put the good stuff in if I'm climbing.

I'd almost say do the mechanical swap first, then swap over to the 02 ho computer.

4.7 h.o. swap

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