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Unread 12-04-2013, 01:36 AM   #1
cwig12
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Pulling an EFI from a Junkyard

I have a 258 I6 4.2L with a 2 bbl Carter Carb and I am wanting to go to an EFI system but don't have the $1200 it takes to get a new one. So my next option for the time being is to pull one from a scrap/junkyard. What are some of the cars that I should look for that would have what I need? Anything I need to know in terms of what to look for?

Thanks

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Unread 12-04-2013, 03:29 AM   #2
86cj74.2L
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A V6 S10 Chevy truck or Blazer. That's the TBI mod.

Any 1991 jeep 4.0HO anything. That's the MPFI mod.

Plenty of threads on both.

With the MPFI you will need to come up with a crank trigger system. And that will either require the flywheel from the 4.0 you take the fuel injection off of or the HESCO crank trigger kit. There are plans to make your own brackets.
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Unread 12-04-2013, 04:23 AM   #3
Matt1981CJ7
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I saved this thread for future reference, and I think it answers your question, perfectly.

Here's another good one.

I guess there are benefits to being a compulsive bookmarker.

Matt
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Unread 12-04-2013, 11:11 AM   #4
cwig12
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Thanks for the info guys! I have been reading up on TBI and MPFI and went on the hunt for some scrappers. I found we have a local Pick n' Pull so when I get around to it I am going to see if any of the jeeps like this one http://row52.com/Vehicle/Index/1J4FJ78S8TL203138 have the system still intact and all of what I need. I will be looking for an MPFI, it's already pretty cheap in a junkyard so I might as well get the better of the 2.

Thanks!

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Unread 12-05-2013, 10:56 AM   #5
1986cj
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You may want to read up on a obd1 and obd2 before you take the jump. Both good, but obd1 is easy to wire up and less needed. There are some good threads in here on both. 87-90 4.0s are renix not so great, 91-95 are obd1 and 96 and up are obd2 good system but later ones can run into a lot of problems in a CJ if you have to be emission compliant.
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Unread 12-06-2013, 10:31 AM   #6
Balvar24
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I was looking at switching my BBD out for TBI, even picked up a lot of the components. I got to surveying the difference between the tuned, automatic choke BBD and TBI, and figured out there really weren't that many pros. The old Carters work good when they're clean and adjusted per the manufacturer's recommendation. I'm getting 16-18 mpg, no problem. No studders or hesitations.

For TBI, you need the 4.3 throttle body, engine wiring harness, computer, and knock sensor. Maybe a couple of other small ticket items.
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Unread 12-06-2013, 11:44 AM   #7
jeep1000
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Why not pull a 4.0 outta a early cherokee with the harness and everything? It's a bolt in, EFI, and I believe it's obd1, correct me if I'm wrong or y'all already suggested it.
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Unread 12-06-2013, 02:20 PM   #8
86cj74.2L
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Quote:
Originally Posted by Balvar24
I was looking at switching my BBD out for TBI, even picked up a lot of the components. I got to surveying the difference between the tuned, automatic choke BBD and TBI, and figured out there really weren't that many pros. The old Carters work good when they're clean and adjusted per the manufacturer's recommendation. I'm getting 16-18 mpg, no problem. No studders or hesitations. For TBI, you need the 4.3 throttle body, engine wiring harness, computer, and knock sensor. Maybe a couple of other small ticket items.
If you follow my old threads that's exactly what I ended up doing.

I was all set to go JY TBI cause I was getting tired of Grammy having a hard time starting it cold, tired of the off idle hesitation. Bla bla.

The manifold gasket was the main problem. Or should I say lack of the separate intake gasket stacked on top of the metal gasket. The off idle hesitation was the worn shaft bushings. And dialed in the choke tension on a cold day.

Got all that ironed out but new bushings in the baseplate and...........

If I had to purchase a carb outright for Grammy I most likely would have done the TBI. But everything I did to the CJ needed to be done and operate flawlessly by Monday morning. She doesn't drive stick
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Unread 12-08-2013, 10:14 AM   #9
Colt44
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I did the conversion a few years ago after blowing a head gasket. The parts from a 91-95 Wrangler or Grand Cherokee will bolt right up, though a few mods were needed here and there.

A 4.0 head will bolt on, though a few water passages need to be closed off, which is easily done with JB Weld.
Not only does the later head work better, it fits. If you re-use the 4.2 head, the intake and exhaust manifolds won't fit quite right and you'll be jury-rigging attachment bolts, gaskets, etc.
Also, the 4.0 head is designed for MPFI, and has intake angles that make much better use of the MPFI itself. That advantage is lost with the old head.
There are several different castings available, two of which are much better than the others and those casting numbers are posted in several threads.

Having done the MPFI conversion and driven it for several years, I can't recommend it highly enough.

You'll need a wiring harness for the new set-up. You can either strip out an OEM one, or bit the bullet and get one from HESCO.
After all I learned doing this the first time, in future I'd just modify an OEM harness.

Someone else has already commented on the TPS situation. I went with the HESCO kit, but again, knowing what I know now, if I ever do it again I'd go with the flywheel option.

But check out the threads on this already posted around here; there's more info than you'll ever need.
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