2002 HO VS. Standard - JeepForum.com
 
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post #1 of 6 Old 07-27-2021, 09:03 PM Thread Starter
BilletHorse
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2002 HO VS. Standard

Can I get some clarity from all of you smart people.
From what I read, all Jeeps prior to 2005 (and a few 2005) had JTEC controllers.
If this is true, could an HO engine be swapped out along with the HO ECU?
Is there a bus difference, being that they both are JTEC?

Or can HO cams just be swapped and a tune?

Further down the rabbit hole, will the 2008-2012 dual plug heads bolt up?

Background, my original 4.7 blew the head gaskets then dropped seats, replaced it with a rebuild from Accurate Engines after figuring out it was much cheaper to buy a rebuild than do it myself. They used the redesigned pistons with the lower top ring placement, and I maybe have 30k on it and there is zero blow-by.

My GB had 250k on it and runs really good, I bought a pigtail for the IAT and modified it with a resistor (10k I believe is what I ended up with after testing), and running a resistor pack in the transmission pressure sensor to raise line pressure, clipped the TCU feedback wire to the ECU to eliminate torque management, and put on a flowmaster Super 50. I am really pleased with part throttle performance (which I think the intake is tuned for) but there isn't a lot of meat after that.

I know it is a small engine in a big-ish vehicle, but I really feel like there is a lot left on the table if I could just figure out where the issues are in the engineering/tuning.

Sorry for the long post!

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post #2 of 6 Old 07-27-2021, 11:04 PM
03WJinAZ
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This is all way over my head, but i know MartinBuilt (on you tube) swapped in some cams from an 08+ 4.7 that have a lot more lift and duration. He has a tuner to compensate, has lots of other mods also... no idea what the end result was for power, but the newer 4.7's are factory rated quite a bit higher. Might be a good place to start...
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post #3 of 6 Old 07-28-2021, 08:50 PM
sdg3205
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I dont think 99-01 used JTEC, but the user here JTEC would probably know.

Yes, if you swap IN an HO into a non-HO jeep, you'd ideally use the HO ECU so you could run various octanes, but you'd also want the key and SKIM which are married to the ECU.

As for the later 4.7 heads.... no, unless you have a plan to operate the additional 8 spark plugs?
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post #4 of 6 Old 07-29-2021, 08:29 PM
cDee63
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You can put an HO in a standard 4.7 however the HO has a different computer and more importantly a different engine harness, the HO has knock sensors in the valley where the standard does not. If you could get the entire engine with harness and ECU that would be ideal.
The HO cams will bolt right in a standard 4.7 and will give a noticeable increase in power. If you can find them IMO it is worth the installation effort. The earlier (99-03?) were jtec, 3 plugs on the PCM, later were NGC, 4 plugs on the PCM. That being said my 04 is jtec and it is supposed to be NGC... The dual plug heads as far as I know do fit any 4.7, and it is my belief the standard single plug harness will work with the dual plug coil but don't quote me on this. Do check out martinbuilt, he knows 4.7's quite well. Pretty cool dude as well, I have quite a few conversations with him regarding engine mods and tricks. I am gathering at the moment the goods to do a full swap this winter, I have a 2009 complete engine I plan on rebuilding to replace my 04 standard 4.7. There are ways to put the 08 and up intake and throttle body as well on the earlier ones, it takes some cash layout for the adapters to do it or some fabbing.

2004 Limited, 4.7 modded slightly, IRO 3" RockLink LA front, adjustable SA rear, Bilsteins, Addco bar, JKS disconnects. Coming attractions include 242hd, IRO SYE and Woods DS right after the new engine/trans..
1974 Ironhead Sportster, total custom
High speed, low drag
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post #5 of 6 Old 07-30-2021, 05:04 AM
mak_v8
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@cDee63 ,
I really can't wait to see that engine swap!

Grand Cherokee WJ 4.7 V8 HO. m.y. 2002
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post #6 of 6 Old 07-30-2021, 05:24 PM
cDee63
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If I cannot do a tone ring swap I might be up the creek with a full swap.

2004 Limited, 4.7 modded slightly, IRO 3" RockLink LA front, adjustable SA rear, Bilsteins, Addco bar, JKS disconnects. Coming attractions include 242hd, IRO SYE and Woods DS right after the new engine/trans..
1974 Ironhead Sportster, total custom
High speed, low drag
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