Fuel Injection?

[ScreamingEagle82]

So I am a new owner of an 87 Sedan and I was wondering, if I wanted to convert to a fuel injection system, where would I start? What I mean is, does anyone have any idea where I could find the system to use. It's the in-line 6, and currently has a carb. Would it be difficult to do this conversion? Has anyone done this before? Any and all advice would be welcome and appreciated. Thanks.

[kajsdf]

i am not 100% on it but i know it involves pulling the intake, fuel rail and computer from an early-mid 90s donor jeep cherokee or wrangler. there is a write up contained in the 4.0 head swap article in the eaglepedia. personally i feel the motorcraft carb swap is the easiest option to improve general driveability and fuel economy.

there is a thread on some other jeep forum that goes into a lot of detail, but it too is a 4.0 head swap article

[captspillane]

All the information is here if you start cruising through the threads. The cheapest and simplest way to make your Eagle run well is Gronk's Motorcraft 2150 Carb conversion. Then there is the Howell TBI (Throttle Body Fuel Injection) kit. That is fairly simple but it costs $1200 dollars. Then there is the Jeep Cherokee version that is called MPI "Multi-port Fuel Injection." That is available in a kit for about 2500 dollars. It can be built from junkyard parts for considerably less.

I suggest reading through these two links.

http://forums.amceaglenest.com/index.php?topic=37553.msg306794#msg306794

http://www.amceaglenest.com/images/PDFS/Joshs%204.0%20Walkthrough.pdf

[maddog]

if i remember right that is brownbear's old Eagle which already has gronk's kit on it so the only thing he can do to get better mpg and power is to go fuel injection.

[ScreamingEagle82]

Maddog is correct. It used to be BrownBears and already has the Gronk on it. I personally feel I could get more power, or at least more responsive power from the fuel injection system. Let alone better mpg's. I figured it was going to be expensive, at least for a kit. I appreciate the links and I'll be sure to check them out. My fuel economy is terrible right now. I'm not expecting miracles though.
I know there are some purests out there, but it's already been modded, and I think making it more economic wouldn't be too blasphemous. lol.

[kajsdf]

even a carbed 4.0 head swap would help out with efficiency and power. fairly economical...i would especially do that if you were doing the efi upgrade to maximize benefits

[ScreamingEagle82]

It's kind of funny to admit this, but this is the first Carbed vehicle I've ever owned. By the time I was old enough to drive, they were unheard of. So I guess I'm kind of paranoid about keeping it carbed. I guess I just need to weigh my options and figure out which would work best for me. Thanks for the advice guys. I'll be sure to keep you posted.

[doc65]

Young'uns

[kajsdf]

its my first carbed car too...honestly, i like it...keep it analog, no computers. frustrating at times, but overall simpler

[maddog]

By the time I was old enough to drive, they were unheard of.

the same is true for me but i think carbs are better than injection as there is less to go wrong but that's just my opinion.

[Pat]

Young'uns

Ditto!!!

[GRONK]

If this is Brownbears old eagle I can help.  I remember we had a few issues working through the install but I can definitely get you going in the right direction and make sure everything is as it should be.  I have Jeeps and eagles getting low 20's at sea level and high teens at elevation (I average 19mpg in a CJ5 running strong as can be)

My direct email is: [email protected]

Send me some good pics and info on what you currently have and I'll help make sure everything is right.

[txjeeptx]

I'll assume your car has a 3-speed automatic, which would mean it has no overdrive gear in the transmission, so the engineers at AMC opted for high ratio axle gears to give the car a better highway-cruising engine speed at a sacrifice of acceleration performance getting up to highway speed. If you seldom drive long distances at highway speeds, then this trade-off that the engineers made has a large negative impact on your fuel mileage and acceleration performance.

Check your axle gear ratio to see what it is(small tag on one of the differential cover bolts will have stamped numbers, one of them is a X.XX format, which is the axle ratio). AMC liked to put gears that are way too high into the axles to try to get better fuel economy at highway speeds, but this sacrifices city driving fuel economy, since it hurts acceleration performance. If your car has high axle gears(2.53 or 2.73 were common for automatic trans cars), but is rarely driven on the highway, and/or has larger tires than the stock size, then you will see more improvement in fuel economy with a gear ratio change than you will from anything else. If you really want better fuel economy, you'll benefit much more by swapping in a 5-speed manual transmission with overdrive and lower ratio axle gears to improve acceleration. Really really really want economy? Wrong kind of car - buy an import econo- -box or a bike.

Fuel injection should be swapped in to improve driveability/start-ability & to improve performance, not so much for fuel economy. If you go through the trouble of installing fuel injection without addressing the possibility of an overly high final drive ratio, you will not see any improvement in fuel economy. Tire size is a big part of final drive ratio, and oversize tires make for poor economy based on increased rolling resistance and weight, not just the increase in final drive ratio due to the increase in diameter. Want economy? Try smaller and lighter tire and wheel combos. Want to look cool with big tires? Forget about economy. You can get some of the economy lost on big tires back by swapping in lower axle gears, but this doesn't address the increased weight and rolling resistance, it only corrects the final drive ratio to put the engine back into its most efficient operating speed.

That said, fuel injection can be a huge improvement in driveability and performance-ability over a carbureted system. The 4.o HO head is a better flowing design, and, coupled with the 4.o's fuel-injection-designed cam, is the real driving force behind why the 4.o makes nearly a hundred more horses than the 4.2, not just the fact that one has fuel injection and the other has a carb. Just swapping in fuel injection without swapping in the better head and camshaft will make only a small gain in performance over the MC2100 carb, which is a great carb, vastly superior to the factory Carter.

If you want to improve performance, I'd recommend swapping in a 4.o head, and a 4.o camshaft, if you're really ambitious, but its nearly impossible to swap in a camshaft with the engine in the car. Swap in fuel injection only if you aren't capable of learning the nuances of carburetor tuning(or don't care to bother with learning the lost art of tuning), and just want to be able to turn the key every day and have a computer do the tuning for you.

One last note - usually when you start making performance a priority, economy goes out the window. Dammn the MPG, full speed ahead!

[ScreamingEagle82]

Thanks for the info TxjeepTx. I've thought about it for a few days and I think I'm going to go with the 4.0 swap and leave the carb. It seems like a workable option and since I don't plan on driving it long distances that often, it should be ok for me. I think I'm also going to check out this gear ratio issue and see what I can do from there. It's like spiderman says, with great power comes a great lack of economy.....or something like that. lol. Seriously though, thanks for your suggestions.

[EagleW]

I have a factory 1983 Eagle Wagon with a I6 258.  The carb is also factory.  I am wondering what gains in HP or reliability I would see if I did the following and what what it would take to do as far as electrical: (using parts from a 4.0 jeep engine)

option A:  Swap the head and cam shaft. 

option B: Swap the manifold, injectors, and throttle body.

Option C: all of the above.
 
also if it's possible and what years I could scavenge from?