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Unread 01-25-2010, 10:34 PM   #1
smitty586
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CJ Fuel Injection?

Ok, I'm sure this has come up before. I have an 83 CJ 7 with 119,000 miles on it. I have recently installed the EMPI Webber style carb on it. The new carb is running fine, but is fuel injection worth putting on a CJ? Moreover, is it practical? I love driving my Jeep, but I want to try it all the time and everywhere. I want to take it on long rode trips at a moments notice. But as it stands now, I don't. I don't because number one, I'm worried that it wont make it there and back. Im worried about dependability. And, gas mileage is an issue too. Would fuel injection change these issues? My current engine seems to be running well, but I am worried about the high mileage. I have looked at getting a newer Jeep, but I just don't like them near as much as the classic CJ 7's. Thank you for your input.

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Unread 01-25-2010, 11:01 PM   #2
h2ojeep
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Fill out your jeep model and engine so that others can have an understanding of what you have to better answer your questions.

Fuel Injection:
IMO, I would NOT spend the money to add FI on an engine with 119K miles. It may be running fine, but it could be a pretty "tired' engine. I would think about putting money on doing a OH, and then FI. and if I could not do both, I would put priority on rebuilding the engine.
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Unread 01-25-2010, 11:23 PM   #3
smitty586
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my engine is the straight 6 258,4.2. I haven't done a "complete" overhaul, but I have replaced the valve cover and gasket, the fuel pump gasket, oil pressure sending unit, oil pan gasket, and distributer gasket.
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Unread 01-25-2010, 11:56 PM   #4
amcjeeper
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Mopar multi point fuel injection

I had the MOPAR kit installed on my 83 cj7 about 8 years ago and would do it again in a heartbeat. When it was put in my jeep had around 90,000 mi on it. The only engine internals that were replaced was my timing chain at 72,000.
I ran Mobile 1 synthetic oil in it as soon as I bought it and was pretty good at maintaining it though. The one thing that I had to do was replace the fuel tank with a fuel pump mounted in it because during the summer in Boulder Colorado the fuel would get so hot that the jeep would cut out. The fuel was heating up and turning to a mist or vapor, I am not 100% sure about the state of the fuel but something like that. The new tank had the fuel pump installed in the tank so the fuel would keep it cool. In stock form the fuel pump is mounted on the outside of the tank above the rear diff. I have only had to replace the fuel level sending unit/filter once and the pump has been going strong now for over 8 years. When I got the jeep it was in good condition. If you plan on keeping it for a while maybe the rebuild first then the fuel injection, would be the way to go.

Last edited by amcjeeper; 01-26-2010 at 12:09 AM..
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Unread 01-26-2010, 08:51 AM   #5
Happy Joe
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I injected (multipoint) my first 258 in the late 80's/very early 90's and it worked so well that I said "I will never have another carburetted engine" in a vehicle longer than it takes to make some trips to the junkyard to gather the parts or get an OEM injected engine.... and I haven't. Don't mess with throttle body injection (its basically just an electronic carburetor), multipoint (preferably sequential) is the only way to go.
Carburetors don't even come close off road or maintenance/reliability wise.

A pusher pump at/near the tank will eliminate the vapor lock issues common to trying to suck gasoline long distances, or through a filter. Putting the fuel pump in the tank was one of the biggest mistakes that I ever made (Just try dropping a full fuel tank, without a floor jack, by yourself, in the dark, along the interstate, to fix a broken wire inside the tank).

Enjoy!
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...a well prepped, well driven, vehicle should do well in any terrain, including the highway.

Carburetors became obsolete during the last century... do what ever it takes to get fuel injection...It makes bigger grins off road.
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Unread 01-26-2010, 09:22 AM   #6
2fast4u
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If you are iffy on your motor then absolutely spend the money to rebuilt it first. Fuel mileage isn't going to mean squat if you are stuck on the side of the road with a rod hanging out of the block. In my opinion there is no substitute for fuel injection. The tuneability as well as the reliability (on and off road) are well worth the money.
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Unread 01-26-2010, 09:48 AM   #7
1986cj
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I would rebuild you motor if you are afraid to drive any distance. If it is running fine and with only 119,000 on the clock, is there something else in the back of your mind that you think may fail? I have a 1986 CJ7 258 T5 3:31 gears 30 950 15s BFG ATs on it and I average around 20 mpg on weekend trips with a mixture of highway and wheeling.. It has the carter bbd carb and over 188,000 miles on it, but I would not hesitate to jump in it and drive it anywhere, anytime. I am replacing the motor this spring with another rebuilt 258 in the garage on the stand now and have built a tbi system for it for it. I have about 150.00 in the fuel injection for it. It is a rebuilt junk yard system with timing control, and I just wanted to see how cheep I could put one together. I am now thinking of putting on a 4.0 head and a junkyard Mopar type injection conversion from a 4.0 HO XJ. To me any fuel injection is better that a carb but the Gm tbi is so simple to build and does work. I think you should sit back and really think what scares you about driving your Jeep, and fix it. Heck if you cant dive it at will, It is not going to be any fun at all to own one.
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Unread 01-26-2010, 12:42 PM   #8
h2ojeep
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Quote:
Originally Posted by smitty586 View Post
my engine is the straight 6 258,4.2. I haven't done a "complete" overhaul, but I have replaced the valve cover and gasket, the fuel pump gasket, oil pressure sending unit, oil pan gasket, and distributer gasket.

I was more referring to rings and bearings, timing chain, etc. and not gaskets and seals that dont really add to the substantive longevity of your engine.

Other post are implying that you are not comfortable with your engine, I did not get that from you, you obvious feel that your engine is strong and sound. By all means, you know the engine better than any other, and I would enjoy it depending on your comfort level. I drive a 304 with 100K miles and while I trailer it to Colorado etc, I could drive it to Colorado, but choose not to (because I like the smooth ride of the long wheel base, quite, satellite radio/cd, a/c, comfortable seats, 85 mph even while towing of my F150 when doing a 600 to 1000 mile trip.)

However, If I were considering putting on FI on my 304, I would do it on a low mileage engine, just because it make better logic. The cost to add FI is probably at least twice what a rebuild would be. I am saying "first things first" and having a good platform to add fuel injection to, IMO is more important that the FI.

As I state in my first post, If you are willing to spend the bucks, what would be great would be a new engine (ie freshly rebuilt) AND then add the FI.

I dont know if you can add the "teamrush" up grade to your model jeep, but if you can, do it. It is very easy to do and, for less that $150 (I did mine much less) you can make a good running jeep run even better and increase fuel efficiency.
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Unread 01-26-2010, 02:42 PM   #9
RARECJ8
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Quote:
Originally Posted by Happy Joe View Post
Putting the fuel pump in the tank was one of the biggest mistakes that I ever made...

Enjoy!
interesting... I have the mopar EFI kit in now for about 6 years with great success, except for fuel delivery issues. I mounted the pump as set forth in the instructions and about every 6 months or so, it would start sucking air and die. Try re-priming an in line fuel pump along side the road at night-- i did. Actually, i used my leatherman to swap out the pump for a spare and still that didn't help. (holding flashlight in my mouth) My Areo tank has the in/out ports on the drivers side and the hoses cross over the exhaust, between the tub and frame. They would consistently dry out and allow a microscopic pin hole to develop and this caused untold headaches. I used EFI specific hose clamps, etc. Even used a home brew stainless heat shield to no avail.

The hesco.us site has a very helpful forum for these and similar issues. Now with the in tank pump the supply line runs all along the pass side no where near the exhaust.

One time i was DOA on a trail run and could not get the pump to prime and hold pressure at the fuel rail. (buy a screw on type EFI fuel pressure gauge, it is priceless in troubleshooting fuel delivery issues). Having low confidence in the jeeps reliability, i carry an assortment of fuel lines, hose clamps and a spare 12 VDC pump. I simply by passed the fuel tank all together and extended the supply and return lines to the rear mounted jerry can of gas and added the temp in line pump. ran a jumper from the old pump to the temp pump. I drove home nervous, waiting for it to stall any time, but it worked.

After dealing with sudden loss of fuel pressure driving down the road i worked with Mr. Hurley at HESCO and we designed an in tank pump for the Aero tank. Was a pain to cut the holes but IME, it has performed flawlessly for several years . ( knock, knock on wood!). I keep the old set up in place and just blanked off should i need to use a back-up pump.

good luck, but i have not had any issues since going to the in take pump.


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Unread 01-27-2010, 08:53 AM   #10
Happy Joe
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I had experienced the high altitude hot weather vacuum lock several times before I looked to see that manufacturers had apparently solved it by placing the fuel pump in the tank. I copied the system and ran trouble free, for a while...

After my first in-tank pump failure, I started carrying a spare high pressure injection pump, enough fuel line to run the length of the jeep and some wire to power the pump. (Yes; it is possible to snake a hose through the filler neck and into the tank).
I had occasion to use it after another in-tank failure (the connecting hose between the in-tank pump and the fuel line blew out inside the tank).
After this I promptly removed the in-tank pump, and installed a low pressure pusher pump immediately in front of the tank to supply the fuel line to the high pressure pump near the engine, this system has proven trouble free on the dozen or so vehicles that I have injected. If it should fail in the field it would be easy to repair (no tank dropping necessary).

In my dotage I seem to have become a wee bit wiser;
'Tis a poor planner that puts themselves in a position where they may have to fix something that is very difficult to get at (I can just imagine trying to repair an in-tank pump on a snow run, in a mud pit, or hanging off the side of a mountain)...

Enjoy!
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...a well prepped, well driven, vehicle should do well in any terrain, including the highway.

Carburetors became obsolete during the last century... do what ever it takes to get fuel injection...It makes bigger grins off road.

Last edited by Happy Joe; 01-27-2010 at 09:03 AM..
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Unread 01-27-2010, 08:59 AM   #11
CoryA
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you know, I've been doing a lot of research in the past year or so about what to do with my 4.2

to be honest for the price of a fuel injection kit it seems better to get a nice chevy fuel injection 350 off of craigslist. There are a lot of newer vortec engines with low miles that were pull outs that you can get fairly cheap

(last week I saw a 350 vortec 700r4 tranny and transfercase for 600 bucks and it had 80k miles)

if you have the mechanical abilities this would be the way to go in my opinion
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Unread 01-27-2010, 10:01 AM   #12
mvigo
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I have the MOPAR fuel injection kit made by Hesco and I have completely forgotten about all the carb problems I had. The only time that I experienced vapor lock in the fuel lines was driving through the Sacramento Valley when it was 110 degrees. I have since solved that problem by wrapping all the fuel lines with exhaust tape and I have not had a problem since. Knock on wood. And, yes, I drive my Jeep everyday.
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Unread 01-27-2010, 10:50 AM   #13
Ken4444
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I think that switching to fuel injection is a good move for most people because it provides better gas mileage and easier starting in cold weather. But remember that a carb or fuel injection system is only one piece of a complicated puzzle. You need all of the components around the engine to work correctly for the engine to run right. You say the carb runs fine, but yet you're worried about reliability? Has the Jeep proven to be unreliable? I would hate for you to drop the money for FI only to continue to have problems in other areas.
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Unread 01-27-2010, 01:03 PM   #14
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all good points. one easy fix for access issues is to cut a round hole in the rear tub directly above the sending unit/pump assembly. Then add a round cover and screw/bolt down. So if there is a need to get to them, never a need to drop the tank. There is a write up on this forum IIRC about that.

Going to a Vortec motor is a nice upgrade, but consider then the ripple effect of having to deal with other issues like motor mounts, bell housing, cross members and drive shafts not to mention computer, etc. moreover, the I6 has awsome low range torque making it a real trail tractor-- the SB 350 variants are nice but in my observation in the field, don't lug down and crawl at 800 RPMS like the good ole 258.
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Unread 01-27-2010, 08:47 PM   #15
smitty586
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Quote:
Originally Posted by Ken4444 View Post
I think that switching to fuel injection is a good move for most people because it provides better gas mileage and easier starting in cold weather. But remember that a carb or fuel injection system is only one piece of a complicated puzzle. You need all of the components around the engine to work correctly for the engine to run right. You say the carb runs fine, but yet you're worried about reliability? Has the Jeep proven to be unreliable? I would hate for you to drop the money for FI only to continue to have problems in other areas.
What I mean when I say I'm worried about taking it on long trips is that the miles on the engine are up there. Its running fine, but I've heard that CJ7's engine life is about 125-150K. However, I have started to replace alot of the gaskets, to include the valve cover, distributer, fuel pump, and oil pan.
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