This might work.

 

I probably wouldn't use a mechanical relay though. Something solid state like an optocoupler would be better. http://en.m.wikipedia.org/wiki/Opto-isolator

 

My original idea was to use a relay set-up to switch between everything and literally just have one switch to go between the systems, but I decided against it as it was something else that could fail somehow and just make testing and getting it going more difficult. Eventually, I will have a set-up like that if I don't decide to just say screw the stock set-up entirely.
I would like to rebuild another 4.0 I have and make something out of it and maybe even turbo it. And when my trans goes out put a manual in, so at that point I'll probably be looking at making the harness for the vehicle entirely from scratch. This is all of course going to be after a few years and once I can get those green squares with faces to start growing in my pocket.

 

ok bad timing on that reply of mine. haha I haven't heard of those optocouplers before

 

http://www.diyautotune.com/catalog/d...kit-p-389.html

check this out

 

Haha wow I can't believe they came out with that. I really hope it wasn't out when I bought mine, but mine was quite a bit cheaper than that set. But it sure would've saved a lot of headaches...

 

I just got off the forum site for my RX-7 and had to double check that I clicked the right app because I never hear of Megasquirt on here and all the 7 guys rave about it all the time. Its cool to see someone taking this on in a Cherokee!

 

That RA Designs shifter is the bees knees. I drive every day in steep mountain roads and being able to use 2nd gear is awesome. I prefer to use it on some trails over the stock aw4 TCU as well.

Nice work with this man. I'd like to see this setup for the renix 4 bangers- I would think it would even be simpler with a single throttle body...

And everyone else- If you're at work, don't try to go megasquirt dot com.

 

I'm genuinely interested to see how this turns out. I'd be curious to see if there are any HP or fuel economy gains to be had. Subbing up on this for updates.

Keep us posted!

 

Glad to see another rotorhead on here. Because my 94 doesn't have a tunable ecu, I to have been watching and subscribed to your thread.

 

I'm really glad to see how many people are following this. Fair warning that progress may not be made extremely fast as I am in college and part of a design team that takes all my free time. I will be trying to work on the MS set-up during my Christmas break from school, which is only a few weeks, but I have to put an exhaust on first (they don't run too good with mud in the cat). So keep bugging me and hope to see some real updates in a couple of weeks!