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Unread 07-15-2007, 02:48 PM   #1
IJP2
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4.0 Fuel injection on 4.2

I thought I saw a write-up on doing a 4.0 injection swap on a 4.2. Does any body know if this is possible. I thought that doing it required re-tapping the head so that you can swap the intake manifold with the 4.0's. But I may be confusing this with something else. Any help would be appreciated. I tried doing a search on this and looked in the FAQ but no luck.

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Unread 07-15-2007, 03:06 PM   #2
goatboy
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I put the Mopar kit on my 4.2, however, it contained a new manifold...essentially, it is the FI from a 1994-95 4.0...if the heads are different, you might be able to source a manifold only from Hesco, who makes the Mopar kit...
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Unread 07-16-2007, 01:15 PM   #3
IJP2
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Sounds like an idea. How much was everything? Was it pretty easy install
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Unread 07-16-2007, 03:15 PM   #4
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I've currently got a fuel injected 4.2 in my Jeep. The shortblock was out of an 88 XJ and I took the head/intake from my 4.0 and put it all on the 4.2, I only had to do a few minor mods to make it work. Just fill the water jackets in the head to make it go on the 4.2 I also had to cut the front of my crank a lil bit to get the serpentine pulleys on it and made a lile bracket for my coil to bolt to and cover the mecch fuel pump hole. Other then that, run awesome and gobs of torque down low.
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Unread 07-16-2007, 03:46 PM   #5
northjeep
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go to the junk yard
get a 4.0 head and everything to the TB. I mean everything...injectors, fuel rail, FPR, the works.

Then find yourself a good programmable after-market computer and even fire Electronic ignition.

I suggest S.D.S. EFI. ( http://www.sdsefi.com ) Great computers...really reasonable prices. The EM-4 F is an all in one ignition and EFI unit.

If you dont want to go to all that length:

Junk yard source the 4.0 intake, injectors, fuel rail + FPR, TB and wiring harnes.
Yank the computer and make the conversion.
you will need a new gasket set and will have to grind the alternator mount on the intake manifold to make it fit in the 4.2 application...

I highly recommend going Electronic Ignition.
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Unread 07-17-2007, 08:16 AM   #6
IJP2
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Wow, it doesn't sound as complicated as i thought it might be to make it work. You know I do remember reading something about filling in the water jackets. Man i wish I could find that thread. It was a whole right-up on it. I will start looking around the junk yards and begin collecting my parts. Oh one more thing. I have to pass the smog test one last time. There is a new clause that states that any vehicle that was made before 95' no longer has to do the test, but it must first have passed it before the end of 05'. I was In the Air Force and stationed in North Dakota When i bought the YJ in Illinois but since i was stationed out-side of the state i got a waiver. But now that I am back I have to pass one last time. So my question is,(finally I know, LOL) would I be able to pass the smog test with this conversion. I would think I would since its more efficient.
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Unread 07-17-2007, 11:04 AM   #7
TommyT
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I just installed a 4.0 MPI...

...on my '87 Wrangler. Then I took it to the Smog Check station. Passed with fly'n colors. If it'll pass here in SoCal, it'll pass anywhere. Just make sure you get EVERYTHING from the donor car...charcoal canister, thermostat housing with coolant temp sensor...everything...and hook it up properly. Sounds intimidating but it's easy.
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Unread 07-17-2007, 03:43 PM   #8
Prowler
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Heres what I came up with for when I did the swap on mine. Hope it helps

http://jeep.off-road.com/jeep/articl....jsp?id=277013
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Unread 07-18-2007, 12:03 AM   #9
goatboy
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Regarding my Mopar installation, it was not brain surgery, but it was a pretty involved installation... It was a kit, so it was a lot different than you goin out and sourcing an FI from a junkyard or whatever...the kit was very complete, but I would not recommend it to a novice mechanic...
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Unread 07-19-2007, 10:32 AM   #10
IJP2
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Thanks Prowler, That helps out allot. Now I have to make sure I get everything I need. Like the charcoal canister and thermostat housing that TommyT mentioned. I am going to make sure i have every last thing, because I hate running back and forth. Thanks for all your guys help.
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Unread 07-19-2007, 11:41 AM   #11
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Quote:
Originally Posted by TommyT
...on my '87 Wrangler. Then I took it to the Smog Check station. Passed with fly'n colors. If it'll pass here in SoCal, it'll pass anywhere. Just make sure you get EVERYTHING from the donor car...charcoal canister, thermostat housing with coolant temp sensor...everything...and hook it up properly. Sounds intimidating but it's easy.

Were there any issues with the smog? Visual inspection issues? Did you have to go to the referee? I have been thinking about the howell tbi, since it is CARB approved, but I like the junkyard option better if it's possible. Do you have any details of what it cost and the steps?

Last edited by jbolty; 07-19-2007 at 05:50 PM..
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Unread 07-19-2007, 05:46 PM   #12
Douglas S.
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Here's a write-up www.jeepforum.com/forum/showthread.php?t=356768
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Unread 07-19-2007, 05:53 PM   #13
jbolty
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Thanks. Looks like the classic trade off of time vs money.

BUT the main concern for me is still California smog. When I was getting mine done a few weeks ago I saw the guy before me get failed for having a non-standard air cleaner and a locking gas cap.

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Unread 07-19-2007, 06:11 PM   #14
Douglas S.
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It should be fine considering its stock equipment on an xj
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Unread 07-19-2007, 06:54 PM   #15
schwim
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Hi there guys,

Anyone done the head conversion, keeping it carbureted, and if so, what was the performance increase like, if any?

thanks,
json
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