Digital Tuning Megasquirt Ms Ii/v3 Build.

Discussion in 'Fox 5.0 Mustang Tech' started by madmike1157, Oct 12, 2013.

  1. OK. I've done this once before, but all of the pics were either lost, or deleted...effectively making the previous build worthless. So at the request of the boys in admin,..I've started another. This time the pics to be transferred to some cyber-netherworld so they'll remain in the thread.

    Some may know that I have yet another project that will be fuel injected. Not your average project, I'll need the ability to control fuel, and spark myself. The Megasquirt allows for laptop configuration, as well as allowing me to acommodate several custom D.I.S/crank triggered ignition for one.

    My reasons for going to a megasquirt are really not the point of this thread anyway, so suffice it to say that I'm doing it. Matter of fact it's done. (obviously)

    The first thing you have to decide is whether or not you are up to the task. It requires very little in the way of tools,.but for the sake of getting that off the table, you'll need the following to do the job:

    A 15-25 watt soldering iron. (one with a smaller tip is required)
    A small pair of sharp side cutters.
    A stand mounted magnifying glass.
    Roll of small 60/40 solder, Again, the small stuff.
    Roll of masking tape.
    A wet sponge to clean the tip of the soldering iron.


    The computer gives you your build instructions, cannot be downloaded, the guys at DIY autotune keep changing stuff so they keep control of the documentation.

    The first thing you have to do is to assemble the Stimulator. The Stimulator is a kit that when finished will allow you to simulate a running engine to the MSII once it's built. It also allows you to check certain build steps for functionality as you go along.

    There are two different kits offered, and I've built them both. They cost about 50-70 dollars, budget accordingly. Can you do without, and just build the computer? Yeah you could,.......Would you want to given that the thing offers the piece of mind in the knowledge that your ECU is working properly before you even turn your key.......It's probably not a good idea.

    I chose to buy the more expensive Jim Stim. The major dofference is the things ability to even simulate a running crank triggered ignition. Given that I'm going to run a crank's a no brainer.

    You'll start w/ a bare board,..and a pile of plastic bags loaded w/all kinds of doo dads:

    The kit is actually a test. If you can build the Jim Stim, you can build the ECU. Of the two stimulator kits offered, It is waay more difficult to build than the standard stim. That said, before you invest the 300.00 in the computer, might just wanna buy one of these to test your skill set.


    There are several different I.C.'s that go into this project. The first you'll encounter is the lowly resistor. Kind of a Honey badger, just don't care how you install it...(as long as you put it in the right place).
    It really is pretty straight forward...the instructions tell you what bag to look for, and the circuit board is labeled at each location, You bend the resistor to fit the holes, and solder it in place. Once the soldering iron is hot enough, the solder will instantly melt the second it touches the iron. Each connection therefore takes less than a few seconds to make.


    Once soldered, I flip the board over and snip the legs off flush with the board.

    So it begins. The first 18 resistors in place.


    Another dumb circuit. These little doo dads kinda look like the USS Enterprise of Star Trek. Doesn't care which way you install it. They are next on the list.

    There are several diagnostic Led's that are installed. They are the first circuit that is oriented to go one way. It is determined by a shorter leg. The instructions again are very specific, telling you which way to orient that shorter leg.

    Diodes come up next. They are orientation specific...identified by a colored band at one end.
    You can see the location for the diodes with the polarity designation clearly marked....(like the D2 right above the word diode)

    Transistors are dealt with next. Kinda a pain in the ass because the pins are so close together when it comes to soldering them. My JimStim board had the pin orientation different than most transistors (triangular oriented as opposed to inline) and made it easier to solder.

    Three hours in and the board is done.

    Suffice it to say that I have not listed every single solder connection required to build the thing, can find that here:
    Also, I need to qualify that before these last few "projects" I had never soldered anything remotely more intricate than two wires together. So....bottom line if I can do it.......

    This leads to assembly of the entire Computer. This project to be completed w/i the next week.
    #1 madmike1157, Oct 12, 2013
    Last edited: Oct 12, 2013
  2. Show us what the bottom side of the board looks like...

    If you are anything like me, there was a time when I could do work that was as good as any NASA electronics tech. Good enough to go on the Space Shuttle flight into orbit. Not so anymore... time and trial have taken their toll on eyesight and the steady hand needed to do the job.
  3. o0es.jpg

    OK,......Now understand MR. Richker.......nobody said I was trying to solder aerospace circuitry.
  4. From one old guy to another - looks pretty good....:)
    stangboy likes this.
  5. This is just a test project. I'll spend a little more time with the actual ECU.
  6. I have far less patience than you all when it come to that kind of stuff. I would have needed to use a hammer or something of the like to install all of those parts!
    Looks good There!!
    stangboy likes this.
  7. It's actually pretty easy once you get the iron hot. stuff moves along pretty quickly. There's just a bunch of little details.....
  8. Looks good. I was hoping to have mine started by now, but the budget keeps getting kicked in the nuts by incidentals unrelated to cars.
    stangboy likes this.
  9. I'm sorry.....What is the incidental boot that's doing the kicking?
  10. Nothing specific, just in the middle of a tough spot that people get in from time to time. Hopefully some headway will come soon.

    Anyway, I read something recently about auto tune software for MS but have yet to dig into it. What do you know about it? What little I saw made it sound like it works like a Plug and go FAST system that learns on its own.
  11. Ok here comes the noobie this kind of system only used/needed for a forced induction application? Sorry but I don't know anything beyond the stock computer with a chip. :shrug:
  12. No, it can be used on anything. People use it on motorcyles, snow mobiles, etc. Anything that can be made to be fuel injected can be megasquirted. It is extremely versatile.
    redneck6 and stangboy like this.