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Old 02-17-2014, 03:29 PM
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Dr. Marneaus Dr. Marneaus is offline
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Starting to consider fuel injection...where to start

Hi everybody.

For whatever reason I've been starting to consider the idea of fuel injection on my 1973 wag. For a while i was all dead set on not fancy having electronics under the hood to complicate things, but I have realized it may be nice to increase reliability and capability both on and offroad.

So, i have no idea where to start.

My main reasoning for considering EFI is as follows:

1. Elevation. I regularly gain or lose SEVERAL thousand feet in elevation and this has caused problems on more than one occasion. I live at around 2000', and often travel to about 8500'-9000' or back down to sea level. In the past I have had to pull over and adjust timing to get rid of detonation, or live with the truck running like poo.

2. Offroad. I have been limited a number of times in bumpy or off camber situations where I cannot keep my truck running because it floods. This is annoying.

3. Heat. correct me if I'm wrong, but I believe EFI is an answer to heat soak, vapor lock, etc. Again often times getting up to 115 degrees, I have had trouble (more so in the past than now since I did an e-pump) with surging, vapor issues, etc. Also this combined with altitude has caused interesting situations (where the engine begins to lose power, and refuses to run or run right until cool).

4. Overall reliability. Some days my engine just seems to run better or worse than other days. Temp, elevation, time of year, all of this seems to have effects on how it runs. I often "worry" about how it's going to run on any given day, though normally my worrying is for nothing as it's fine.

Question 1: So, is EFI an answer to these issues?

My plans for the truck are to keep the engine pretty darn near stock. I had originally planned to do a fairly mild rebuild on an engine when the time comes, but I honestly think I'm leaning towards just buying a reman long block, and running my stock 4bbl intake or maybe something aftermarket. My current engine is a 1987, I'm running 1987 ignition, and it's got something like 165,000 miles on it I think. Currently runs pretty well but it's gotta be tired, and there is some bottom end noise (has been for a while, never gets worse though). Before too too long it'll be gone in favor of something fresh. I figure whatever TBI i would go with would just get swapped onto the new motor.

From my reading, it seems like a Howell system would be a great option. It's a complete kit, very simple and straight forward from what i see, and keeping a stock engine, I likely won't need anything with much more upgrading or tuning ability.

Thoughts? Am I thinking correctly on this or is this all just some whacky idea in my head because now that my jeep is actually working i feel the need to tear into it again?
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The Beast Build Thread:Marns '73 Wagoneer Thread
1973 Wagoneer - 1987 360 w/ factory 4bbl - TH400 - D20 - D30/D44
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Old 02-17-2014, 04:35 PM
joe joe is offline
 
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Though I do believe EFI is a better more reliable fuel delivery sytem if designed correctly for a specific application. Not real impressed with the results folks have gotten from scabbing on a system from another vehicle and spend forever trying to dial it in.
So far as your problems 1-4 are concerned. Generally due to vehicle age. mileage. condition and lack of maint skills or time invested. A mega buck EFI system will help ease some of your issues but it's not a magic bolt-on, wire it up, vroom vroom no more maint cure. Most of 1-4 can be reduced or eliminated by losing the 4v carb and going to a correctly set up 2v 2150 and spending the time tuning and bringing everything up to factory spec. More to tuning than just twisting a couple idle mix screws and setting timing especially on a worn 1973 AMC motor. If I were considering EFI I would swap in a complete newer motor(GM?) that's already designed and set up for F/i. No not cheap-n-easy but neither is a good pseudo bolt-on EFI. Not saying your idea is a bad idea at all but for your problems IMHO you're going about problem solving the hardest and most expensive, time consuming way possible. Even back in 73 a bone stock in like new condition set up these things worked remarkably well. If you have the money, skills and time to sort out a perceived magic cure EFI for your all your probs by all means dive in. Keep a log of sorting out issues and time spent. Then share with us. I'm no mechanic but have a reasonable for my needs knowledge of carbs and 12V DC but know my knowledge of electronics and FI isn't up to the task without climbing the expensive, time consuming learning curve. Rather than looking for a one shot magic cure I'd fix sort out what I got. That's just me though.
Best of luck.
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Old 02-17-2014, 04:55 PM
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Yep, do it!

Once dialed in good TBI will beat a carb hands down w/ your list of complaints.

Elevation - you cannot get a carb to be happy w/ elevation changes w/o changing jets etc.
Off camber - you cannot get a carb to be happy w/ severe changes sometimes experienced offroad.

Beauty of FI is once it's dialed in just turn the key and go. Doesn't matter temp/elevation/etc.

I'd contact Bill-USN-1 his system is a little better than Howell, and he'll help you tune it as needed.
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Old 02-17-2014, 05:17 PM
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Also please let it be noted I'm not just looking for some magic cure all to any and every issue that may or may not be present with my engine.
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The Beast Build Thread:Marns '73 Wagoneer Thread
1973 Wagoneer - 1987 360 w/ factory 4bbl - TH400 - D20 - D30/D44
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Old 02-17-2014, 05:25 PM
rocklaurence rocklaurence is offline
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I'm putting a Howell EFI in the Cherokee project. IMO, the Howell and Affordable Fuel Injection are a better deal ($1200-$1400) compared to the other smart units that Cost $2200. However, the smart/self learning stuff is Bad Great Googley MoogleyGreat Googley MoogleyGreat Googley MoogleyGreat Googley MoogleyGreat Googley Moogley!
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Old 02-17-2014, 10:34 PM
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If you pulled a donor harness and wanted to try a junkyard tbi I could help you out in thinning it out, All i'd need is a good wiring diagram. There are plenty of write ups on line so you could do it yourself if your confident in your wiring abilities.

Im no help with tuning the computer though, I havent gotten that far in my project. I have made a few 4.0 harnesses for people and myself, as well as a TPI harness for my current 360, so TBI shouldn't be to hard, probably alot more simple. Just speculating without looking at a diagram.
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Old 02-17-2014, 11:33 PM
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I am in the process of a junkyard build my self. I am gathering parts. I just purchased all the Moates goodies. I can help a little too if you go this route.
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Old 02-20-2014, 05:24 PM
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Old 02-20-2014, 05:37 PM
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If you are an electronics hobbyist, a MegaSquirt computer is easy to assemble. Its main advantage is that there is no chip programming - you connect it to your laptop via a serial (RS232) cable. Then you data log and adjust the maps to tune the MegaSquirt computer. You can also run a dashboard display that streams engine status constantly (maybe there is something like this for the hacked GM computers too): http://www.diyautotune.com/catalog/m...-kit-p-96.html

One of the best aspects of EFI is, once you have it dialed in, you just turn the key and it starts.

The MegaSquirt is meant to be accessible... however, B&G meant it to be an educational project, so you're supposed to learn something in the process.

I'd like to comment about reliability - to me, there is no comparison. Modern electronics are vastly more reliable than the fiddly, fussy mechanical metering of a carburetor. A carburetor is basically a mechanical computer powered by engine vacuum. Kinda like the steampunk mechanical computers of "The Difference Engine." But some people are scared of the potential for complexity, and feel like they have a better chance of fixing a carbureted system. You have the advantage that, when you build and tune the system yourself, the fear of not being able to fix it if it breaks goes away. The GM computers have a "limp home" mode that AFAIK the MegaSquirt does not - so you may want to carry some spares, or go with the hacked GM system if that worries you.
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Old 02-20-2014, 09:34 PM
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Old 02-20-2014, 09:44 PM
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Old 02-25-2014, 12:58 PM
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Dr. Marneaus Dr. Marneaus is offline
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Well if i go from one stock engine to another stock engine, it shouldnt need to be retuned, right?

Also i thought these computers in the systems like howell or holley are "learning" computers that adjust as necessary, however when disconnected from power they lose memory and go back to the stock tune, then adapt from there as the vehicle is driven?
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Originally Posted by FSJunkie
Dr. Marneaus is now officially my idol.

The Mag - The Wag

The Beast Build Thread:Marns '73 Wagoneer Thread
1973 Wagoneer - 1987 360 w/ factory 4bbl - TH400 - D20 - D30/D44
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Old 02-27-2014, 10:01 AM
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ThisGuyUKnow ThisGuyUKnow is offline
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Your going from a stock chevy 350 to a stock amc 360 (in a tbi swap). The computer has a range of parameters that it uses as a base line but can only deviate (or correct) so far. For example the ecm is trying to maintain a specific fuel to air ratio based on readings it gets through the 02 sensor and others. It knows that the fuel pressure is X and the fuel injectors push X amount of fuel and the displacement of the cylinder is X there for it need to run the injector to push Y amount fuel to achieve the correct A/F ratio.

If you change any factor the computer has to learn. For example if you install larger injectors that push more fuel then the computer will fire the injector for 1 milisecond expecting it to push a specific amount of fuel but in reality that larger injector is now pushing more fuel during that time span. Since you are using a 360 you can probably get away with a stock flash because it can correct to what you need but your best results would be to retune so that the base line the ecm is correcting off of matches your application.

That way if anything changes, ie wearing motor parts, the ecm doesnt have to move as far away from its base programing to compensate.

That is how I understand it and I could be way way off here so I am sure one of the tuning experts we have on the board might have better insight into it.
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