The beginnings of a Megasquirt how-to guide

[icingdeath88]

Originally Posted by dragoontwo

Since you guys are more interested in bashing me instead of taking anything I say into consideration here you go. My reply did mean the stock ignitor, and I did not say without any ignitor. I even went so far as to point out where it is. I guess you guys know everything and "you got this".

Not trying to bash. Only ever trying to make sure the info in this thread is clear and correct. If the above was what you meant, it sure didn't seem like it:

Originally Posted by dragoontwo

You should be able to batch fire our coils directly from the MS2 and not need to use the ignitor.

This statement is confusing at best, and needed clearing up.

[BackWoodsBob]

dont' let the door hit yuh on the way out bra.

[dragoontwo]

Originally Posted by BackWoodsBob

dont' let the door hit yuh on the way out bra.

Door? I ain't leaving. I'm going to sit in the corner and watch certain people drive away anyone trying to help. It's entertaining and has happened a few times already.

[BackWoodsBob]

haha, fair enough.

[BRZCory]

Just for some more info, here's how the stock ECU handles ignition, in pictoral form:



Now I'm going to go look through my spare stock ECU for signs of a transistor array, and if I find one, it's going to get real easy real quick. I'm only *slightly* concerned that the logic-level megasquirt outputs might be stressed driving the stock ignitor directly after seeing that picture. Using the stock setup *may* also change the signal from "going high (inverted)" to something else, but I'm doing more research.

The reason for this, is that it shows a setup whereby most of the circuits are usually on (the energy can't flow through the "closed" internal transistors, and so instead flows through the open "ignitor" transistors to ground, turning them "on" and allowing the coils to charge), and when it triggers the gates of the transistors inside the ecu, the power can now flow through them to ground, which cuts the signal to the "ignitor" transistors. They stop flowing, the energy field in the coil collapses, and BANG, you get a spark.

I should make a gif of that. But I'm too lazy/involved in other research right now.

And Dragon, you're more than welcome to help, and I encourage debate and thinking out of the box, but please try and be precise. When you say something doesn't need an ignitor, to a group of people trying to get an ignitor to work, you're gonna rustle some jimmies!

[icingdeath88]

Originally Posted by BRZCory

And Dragon, you're more than welcome to help, and I encourage debate and thinking out of the box, but please try and be precise.

Yea, this got kinda out of hand, I, for one, apologize if I seemed hostile or antagonistic, I know none of us want anything other than to get everything figured out.

[BRZCory]

More interesting things: as far as I can tell, the spark signals go to a daughterboard (the green one between the ecu connector and the heatsink). Unfortunately, I've come to realize that it's a 4-layer PCB, so it's entirely possible that they go elsewhere.

There are at least 3 transistor arrays, two of which are located on the heatsink. I am also sure that the fuel injectors are controlled by one of these, so I'd take a guess that the ignitors are controlled by the other one (as they're the only other high-current driven thing in the engine that would use an array with a heatsink). I'll verify with my multimeter when I get a chance.

and if you wanted to go super-reliable, OEM style, the vast majority of the stock ECU pins (all but 5 of them) are connected with a capacitor to ground (which helps clean up the signals).

But I'll stop talking about stock now. This isn't teh ECU hacking thread, it's the megasquirt thread, and I've got the wrong box in my hands

[BackWoodsBob]

Originally Posted by BRZCory

Just for some more info, here's how the stock ECU handles ignition, in pictoral form:



Now I'm going to go look through my spare stock ECU for signs of a transistor array, and if I find one, it's going to get real easy real quick. I'm only *slightly* concerned that the logic-level megasquirt outputs might be stressed driving the stock ignitor directly after seeing that picture. Using the stock setup *may* also change the signal from "going high (inverted)" to something else, but I'm doing more research.

The reason for this, is that it shows a setup whereby most of the circuits are usually on (the energy can't flow through the "closed" internal transistors, and so instead flows through the open "ignitor" transistors to ground, turning them "on" and allowing the coils to charge), and when it triggers the gates of the transistors inside the ecu, the power can now flow through them to ground, which cuts the signal to the "ignitor" transistors. They stop flowing, the energy field in the coil collapses, and BANG, you get a spark.

I should make a gif of that. But I'm too lazy/involved in other research right now.

And Dragon, you're more than welcome to help, and I encourage debate and thinking out of the box, but please try and be precise. When you say something doesn't need an ignitor, to a group of people trying to get an ignitor to work, you're gonna rustle some jimmies!

All this crazy **** you just said makes me even more weary of getting the MS2. FIC6 FTMFW

[BRZCory]

As for some possibly helpful links:


12-1 tooth (stock svx) ignition setup: MS2-Extra Dual Wheel Manual

6 cylinder COP spark setup: (with a missing tooth 12-1,1 setup, but should be similar for non-missing tooth) http://www.msextra.com/forums/viewto...?f=101&t=41252

I know you MS3/3x guys already have 6-cylinder support out of the box, us MS2 guys need to do a firmware update (just to the latest) and then rewire a little bit. I'm still iffy on how to get the signal out of the box itself, might need an additional D-sub connector, or maybe there are enough wires on the MS harness that we can scavenge some unused pins. Either way, I doubt that my relay board will be able to handle it, so I may be DIYing a new relay board (now that I have a cheap source for custom PCB's).

Also, am I correct in assuming the stock IACV is a PWM control? It doesn't seem to have enough wires for a stepper style.

And what are people using for IAT's? I'll probably use the GM one mounted directly in the center of the intake manifold (or at least in the plenum) because that's where my supercharger will be blowing into, and I'll want a post-boost temperature (as it'll likely be in the mid-upper 100's). To start with though (pre-supercharging) I'll probably just plumb it into the plastic elbow somewhere.

[BackWoodsBob]

The MS2 won't support 12-1 ignition systems?

[BRZCory]

Originally Posted by BackWoodsBob

The MS2 won't support 12-1 ignition systems?

It does, I just haven't found a writeup that uses both the 12-1 AND a 6-cylinder COP setup. The 2nd link is mostly just re-inforcing that it *can* handle 6 spark outputs with the newest firmware, but that there is a little tweaking required.

[BackWoodsBob]

Ah, I see. So you're not going to use wasted spark? You're trying to get sequential everything?

[BRZCory]

Originally Posted by BackWoodsBob

Ah, I see. So you're not going to use wasted spark? You're trying to get sequential everything?

I'm trying to use the stock setup, yes.

[BackWoodsBob]

Originally Posted by BRZCory

I'm trying to use the stock setup, yes.

From my reading, you needed MS2's expansion board to fire sequential injectors...

[BRZCory]

Originally Posted by BackWoodsBob

From my reading, you needed MS2's expansion board to fire sequential injectors...

I have no idea what you're talking about.

Unless you're talking about a GIPO board, but I haven't gotten that far in my research. The Megasquirt "2" IS the expansion board that plugs into the CPU slot. You're still going to need a bunch of transistors (I assume) to go from logic-level to power-level, but that's easy.

It *would* be really helpful if someone has access to an oscilliscope, to see exactly what sort of voltage/power is going to the stock ignitor. That way we could figure out exactly how much juice we need to flow to get this all to work.

And we'd be able to see how long the stock signals cut power to the ignitor (dwell time)