Going Megasquirt

As much as Dan is constantly screwing with and tweaking his Megasquirt, I thought that on our road trip last week, that a "break down" bet would be a sure thing for me...aka: first one to break down or need to tweak something on the side of the highway had to buy lunch....

Well my LS mota burned a plug wire on the way home from our 500 mile road trip, so guess who had to buy lunch...lol.

Must say, I'm impressed with how far he's come with the MS setup, and how flawless it ran during the trip.
So tell me if i have this right.

Our cam and crank sensors are both hall effect so they are considered VR sensors in the manual?

Our IAC is a stepper motor?
Yes they are considered vr though with the cam circuit its wired as opto. I can send you my msq if you want to see it. The iac is stepper.
Ok will do.

Here are a couple of pics of my main board to show where I'm at. I think I'm pretty much done but there are a couple of items I need to figure out.

Since the MAP sensor covers the spare connections, should I solder some wires to the spare connectors just in case I want to use them in the future?

Let me know if you spot anything incorrect :cool:


Are you looking to run sequential or batch? If so you will need a different cam input, bob and I used a 4N25 chip for it. I'll send you some schematics and my msq tonight, just send me your email in a pm. Ill compare your board to mine when I bring my car home next week. Also have you bought an adaptor yet to go from the db37s to the delphi 56 pin ecm connector?

Also you can solder wires from the top and side feed the solder. That's what I did when I added wires to mine. Oh and if you just go to a mapdaddy nothing is in the way! :)
I want to run sequential without using the buick ignition module. I'd love to see your schematic for running the cam sensor.

I haven't gotten an adapter for the db37s to the 56 pin ecm connector. My plan is to head to the junkyard tonight to find an old ecm.

Oh and I didn't know that the map daddy was physically different. I will be going that route so I guess I won't have to worry about the spare connections.
That is what i did originally for testing purposes and it worked just fine. I did decide to change out to the break out board though now because of reliability and it looks better.

I put a small email "packet" together for Chevelle and all interested in seeing it for building a MS3. Its far from perfect but is a good starter.

Thanks Dan,

So just for my understanding, are the 4n25's mainly for circuit protection / isolation?

Also I thought that the cam signal was input via ms3x, not the mainboard? Are the schematics only used if you retain the buick ignition?
Dave that is how mine is installed as well.. you put it that way to allow the map line to go out of the case. He just has the whole assembly flipped upside down for the picture..

Chevelle those schematics are for if you are using the buick inputs you don't need to run the output from the led to the module if you are running cop but everything else is needed. Also the ms3x board was not accepting my cam signal at all so I built an opto circuit and ran it to the main board.

I wonder why the ms3x wasn't taking the cam signal. :confused:

I got the firmware loaded last night! I'm glad it worked on the first try. :cool:

My goal is to have the engine running by Monday. I have a 4 day weekend with no plans but to thrash on the car.

We can run both narrow band and wideband O2 right? But is there even a need to run the narrow band? I figure it is probably useful just to have another sensor to reference.
The ms3x cam signal does not appear to be optoisolated which would be why. I only use wideband since narrow band is useless for any tuning purposes..

Well I dont have the engine running yet, but I have hooked it up to the computer and verified the MAP and air temp sensor are reading correctly.

Thanks again for the drawings you sent me. I am still unsure about the crank and cam signals though. Have either of you tried the direct cam and crank signal yet? I wont be using the same ECM terminals B5 and A11 since I wont have the CCCI on the car.