I Need info on a Fuel Injection Conversion Kit

jcfields1030

New Member
Joined
Oct 20, 2010
Location
Durham
Hey guys, I have a 89 YJ 4.2L straight 6. It wont go over 70 mph (even that is downhill) and has horrible gas milage. I am interested in getting a fuel injection kit but to be honest, have no idea about which one is the best quality/price. I was wondering if anyone could help me get started. I also would like to know if it would be better or even more cost efficient if I just did a swap with a new 4 cylinder fuel injected engine. What are the benefits for each. I'm in no rush to make a decision so I figured I would post here and get opinions before I go out and make a decision.


I also want to let ya'll know that I've had this jeep since 03 and it seems I have replaced EVERYTHING except the engine. Thats why I'm thinking it may be time to go ahead and do that before I buy a fuel injection kit and then the engine finally dies.

Tell me what yall think. Thanks guys.
 
which is more cost effective?

that is what i ask myself, usually... your engine is still strong yes?

in addition, i am trying to get a cab swap going .. i was wondering if you may have any experience.. can you tell me... the cab i want to get is harnessed for a fuel injected 22re ...... i am running a carbed 22r and i am weary about using my old harness.. i hate that i have to take a perfectly saeated one out of the cab i want... do you think i should get another harness.
 
if it were me... id get a 4.0 block and a head from a 91-95 4.0, the crank and rods from the 4.2... and viola... cruzing past 70 in 5th gear...(or overdrive) with a stroked I6
 
Over 10 years ago, I splurged and bought the Mopar MPI kit for my CJ w/258. It was expensive, but saved me the hassle of finding/piecing together a junkyard 4.0L system. It was very complete, I loved it, it was worth every penny.
You need to get rid of the emissions controlled Carter BBD on your YJ. A stroker will be jsut as useless if its still topped with this POS. I've also heard people using a Motorcraft 2100 carb instead, and having great results.
 
gt500swim said:
if it were me... id get a 4.0 block and a head from a 91-95 4.0, the crank and rods from the 4.2... and viola... cruzing past 70 in 5th gear...(or overdrive) with a stroked I6
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you're forgetting the computer, electric fuel pump, return fuel lines and all the sensors as well.:shaking:

Call Painless. Their stuff is expensive but they will help you put a system together. At minimum you'll need the the head, manifolds, tb off a 4.0 Plus the fuel delivery system.
 
Depends on how in depth your mechanical knowledge and ability is. I think it's far cheaper to swap in a 4.0L from a low mileage wreck than to buy the MPI kit. A late model low mileage 4.0L would be a powerful and reliable combination. I did this with my 1983 CJ7 and was very pleased. I also swapped in an AW4 at the same time and the total cost was ~$900 for a 30k mile 4.0L and AW4.

You could also pick up a late model YJ wiring harness (engine and chassis) that was equipped with a 4.0L to make the swap even easier.

IMHO
 
If time and/or money is a concern, the mc 2100 is about the cheapest and easiest alternative. There have been several writeups on this posted in various places around the internet.
 
I had no idea there were this many ways to go about it.

RenegadeT, how did the Mopar MPI kit help the CJ? Did it run better and better gas milage?

jpdudejr my mechanical knowledge/ability is as good as my local shop lol. I have a very good relationship with my friend at his shop and he helps me a TON. This year I am pretty much determined to swap in a 4 cylinder to save gas milage and get ride of the carburetor. I really would love fuel injected because it seems I have way too many problems with the carburetor as it is.
 
jcfields1030 said:
I had no idea there were this many ways to go about it.
RenegadeT, how did the Mopar MPI kit help the CJ? Did it run better and better gas milage?
jpdudejr my mechanical knowledge/ability is as good as my local shop lol. I have a very good relationship with my friend at his shop and he helps me a TON. This year I am pretty much determined to swap in a 4 cylinder to save gas milage and get ride of the carburetor. I really would love fuel injected because it seems I have way too many problems with the carburetor as it is.
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I replaced my 1bbl carb with FI, it helped in so many ways, it was like night and day. Fuel economy was probably much better, but I rarely had a functioning gauge or odometer to measure. With the MPI, it was guaranteed to start right up, jsut turn the key, no dancing on the gas pedal trying to fire it up. Off-road it, it was so smooth, it would just idle along, throttle response was almost instant. With the carb, it would starve for fuel off camber, sputter and die while crawling. Probably had more power too, but I installed the MPI on top of a fresh motor rebuild, complete with cam/lifter kit. If I had the internet resources I now have, I probably would've tried a stroker motor. When I did all this work, XJ's were still in production, the oldest 4.0L HO wasn't that old, donor XJ's werent as plentiful as they seem to be now.
 
jcfields1030 said:
This year I am pretty much determined to swap in a 4 cylinder to save gas milage and get ride of the carburetor.
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This is one of the worst and most expensive options you could go with. A 4cyl only gets 2-3 MPG's better than the 6cyl on the best of days. If you can't go 70 MPH now, good luck getting to that speed in a 4cyl.

Going from a 6cyl --> 4cyl will require welding in new motor mounts, new transmission, new transfer case, fuel lines, wiring harness, and gauges. You'll spend 2-3 times as much with that swap than trying to go with a fuel injected 6cyl. I don't see the point.
 
Do the 2100 swap. Best mod for the money. If you are looking for fuel economy buy a beater car that gets 30mpg.
 
jpdudejr said:
This is one of the worst and most expensive options you could go with. A 4cyl only gets 2-3 MPG's better than the 6cyl on the best of days. If you can't go 70 MPH now, good luck getting to that speed in a 4cyl.

Going from a 6cyl --> 4cyl will require welding in new motor mounts, new transmission, new transfer case, fuel lines, wiring harness, and gauges. You'll spend 2-3 times as much with that swap than trying to go with a fuel injected 6cyl. I don't see the point.
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Thats what I'm starting to think. It seems it will be very expensive with very little benefits.
 
"I replaced my 1bbl carb with FI, it helped in so many ways, it was like night and day. Fuel economy was probably much better, but I rarely had a functioning gauge or odometer to measure. With the MPI, it was guaranteed to start right up, jsut turn the key, no dancing on the gas pedal trying to fire it up. Off-road it, it was so smooth, it would just idle along, throttle response was almost instant. With the carb, it would starve for fuel off camber, sputter and die while crawling. Probably had more power too, but I installed the MPI on top of a fresh motor rebuild, complete with cam/lifter kit. If I had the internet resources I now have, I probably would've tried a stroker motor. When I did all this work, XJ's were still in production, the oldest 4.0L HO wasn't that old, donor XJ's werent as plentiful as they seem to be now."

That sounds to be exactly what I want to do. How do I get started? What should I expect when doing.

What fi did you replace with it? Did you do a complete engine swap with a newer 6 cylinder that was fuel injected?
 
jcfields1030 said:
That sounds to be exactly what I want to do. How do I get started? What should I expect when doing.

What fi did you replace with it? Did you do a complete engine swap with a newer 6 cylinder that was fuel injected?
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I rebuilt my 1977 258, threw in a nice cam and some other goodies, and topped it off with this FIhttp://www.hesco.us/shop.asp?action=details&inventoryID=43025&catId=7577
It is, or was, a Mopar p/n, and available almost everywhere. Right now I can't seem to find it anywhere but HESCO, who developed it for Chrysler when they introduced the 4.0L HO in '91. This kit is brand new Mopar FI used on the 91-95 4.0L HO engines, and it bolts right on to the carbeurated 258's. I sunk a lot of cash in my CJ engine, but it eliminated a lot of wasted time and frustration, and the ned results were awesome.

I considered the Weber carbs, the Howell FI, 4.0L XJ/YJ engine swaps, I chose the MPI kit.
 
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