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Discussion Starter #1
Hello
I'm new to this forum but have been searching on different topics and have found a lot of good information so here goes. I have a 69 Mustang with a carburated 302. I'm finishing the build for my wife to drive and have decided to convert to EFI to make it more driveable and reliable. I have a real dogs breakfast as far as parts I have collected. I started with the 1989 stock EFI comb over intake and harness from a bone yard. Couldn't bring myself to install it due to....it being ugly. Then bought a BBK SSI intake and rail system and a used RJM harness (who I just found out is out of business). The engine is rebuilt and basically bone stock. Should I stick with a stock Ford ECM or try something like a Megasquirt to control everything. I think the RJM harness is made to work with a stock style ECM but I can't find any manuals online for the harness connections. Any help would be greatly appreciated.
 

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If you want to drive the car a lot then stick with the Ford EFI. I'm an automotive computer engineer and a lot of these aftermarket EFI systems won't hold up for very long. The ECU that controls them are often put on the engine or somewhere in the engine compartment where they are subject to high heat and vibration. Additionally most aftermarket EFI systems are centrally fuel injected versus a true multiport like Ford had in 1989. Yet another big drawback is that they use a static map for the enrichment since they have no way to measure the air density. The 1989 Ford multiport EFI system you had is about as good of a fuel injection system as was ever made for the small block 302.

david
 

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I'm running a stock A9L (also out of an '89 Mustang) on my 347 and it works fine with one caveat. While your engine will start and run (sort of) you'll want to put it on a trailer and take it to a tuner for a custom chip to make it run right and get all you can out of your setup.

The megasquirt is certainly an option, but (to me) the learning curve looked to be too high. If you're constantly swapping parts, have the ability to log wideband O2 readings, and are really wanting to learn to tune...then Megasquirt would be great...but for a one time build, just build it...take it to a tuner, let him burn you a chip, and forget all worries of trying to program it yourself from scratch.

Also...I'm interested in what you find with that intake. In particular if it will fit under your hood and if it can be tuned to run with that engine. I did a little research into it myself (also though it looked nice) but couldn't find many people singing it's praises, at least for a mostly stock NA engine.

Phil

p.s. 1 nanosecond google search found this: https://www.factoryfive.com/wp-content/uploads/2012/08/Engine-Controls-87-93-5.0L-FFR-RJM.pdf

Looks like you didn't look that hard.
 

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a used RJM harness (who I just found out is out of business).
RJM been gone for a while. Heard he screwed a lot of folks (didnt deliver) - dont know if true or not. I dealt with him a few times but that was 15ish years ago.

I would use the EEC-IV set up for mass air. Almost all aftermarket setups are TB/speed density. You can tune the ECU with a TwEECer, chip, etc.

Paul
 

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Discussion Starter #6
Thanks for all the replies
Hoosier Buddy, although I searched for at least 10 billion nanoseconds, every search that included RJM harness in it only netted me pages and pages of how they left a lot of people unhappy. I really appreciate the link, I'll be spreading the sucker out on the floor tonight and labeling all the connections. As far as fitment under the hood, I mistakenly said it was going into a 69 Mustang but it's a 69 Cougar and it fits with about 1/2" to spare. When it's finally driving I can let you know how it works.
Since the engine is stock and I'm looking for fuel economy when we use it for highway touring, I was planning on using the stock 19 lb injectors. Does this make sense? I'm an old school carb guy, my 69 Mach 1 has a 408 stroker and I originally put a 750 Holley on it. It ran some good times at the track but I had to fill it at every gas station I passed. When I put a little 650 quick fuel on it I was afraid it might not run well due to the decreased CFM. I lost some power obviously but was able to drive it to the Goodguys meet in Spokane from Northern Alberta and get nearly 21 MPG. If I put 24 lb injectors (in case of future hp mods) will the system compensate now for maximum fuel economy or should I stick with the stock 19 lb.
 

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Discussion Starter #8
The RJM manual says that it's set up for a 5.0 HO firing order which is different than my 302, does this mean I will have to change the camshaft or will a tuner chip allow you to change the firing order?
 

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You can change the firing order in the tune.
 

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The RJM manual says that it's set up for a 5.0 HO firing order which is different than my 302, does this mean I will have to change the camshaft or will a tuner chip allow you to change the firing order?
Custom tune can change the firing order, or you can install a different camshaft. The 5.0 HO & 351W use the same firing order. Do not just swap the plugs on the fuel injectors - it will mess with the computer a bit since it is using the O2 sensors on each side of the engine to determine the result of the calculated fuel mixture. If a cylinder on the passenger side of the engine is fired, the computer is expecting to see the results on the passenger side O2 sensor. Changing the firing order using only the injector wiring will result in cylinders firing on the other side of the engine when the computer is not expecting them to, so it might get a little confused when it looks at O2 sensor output.
 
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