Gauging interest for PnP Megasquirt solution, MS anyone? Options

[JamesM]

For my most recent Megasquirt install i went a different route and had some mini-MS boards produced. It did not make a lot of sense to just have one PCB printed so needless to say i have more then a few empty boards laying around. Now i am trying to decide if it is worth my time and money to build these boards out and sell them as a plug n play solution for d-jet cars.

For those who don't know, mini-ms is electronically compatible with megasquirt 2.2 however the components are arranged tighter on the board and it integrates the relay board all on a form factor smaller then the original MS. My first couple of installs i used a standard megasquirt 2.2 with relay board and DB-37 cable but the mini-ms seemed like the better way to go so that is what i am playing with now.

The setup i a running right now looks almost stock, the mini-ms is enclosed completely in a gutted d-jet brain and plugs directly into the d-jet harness. the only difference from stock is a MAP line running to the brain and the 2 injector ground wires being run back as well. You have to look close to tell its not stock, however i have a feeling i could make it even more stealth by hiding the MAP sensor in an old MPS in order to get rid of the vac line to the ECU. I just have not cared enough to cut up an MPS yet.

The great part about this system is it makes troubleshooting way easier and eliminates the need for stock trigger points, MPS. ECU, decell valve, and cold start injector, though they can all be left in place if desired in order to appear stock. It also allows for cool things if you desire like closed loop operation with a wideband O2 sensor, spark control, rev limiters, traction control, and a bunch of other stuff depending on how far you want to take it. It can be tuned around just about anything, so its great if you want to change cams or go bigger on your motor and still look stock.

So is there any interest out there for this sort of thing or should i just dump the empty boards on ebay or something?

[JeffBowlsby]

One of your big hurdles will be the harness as with all PEFI. The notion of reusing the original D-Jet FI harnesses is not possible or realistic, they are not wired the same as you would need for the MS or any PEFI and there is the very real issue of EMI shielding that the original harnesses do not have. In addition to being old and frail and brittle and corroded and broken and...

Another fundamental concern about MS is that it is experimental. Its ok for those that like to tinker and control their own destiny, but not a good commodity solution for the masses.

[JamesM]

One of your big hurdles will be the harness as with all PEFI. The notion of reusing the original D-Jet FI harnesses is not possible or realistic, they are not wired the same as you would need for the MS or any PEFI and there is the very real issue of EMI shielding that the original harnesses do not have. In addition to being old and frail and brittle and corroded and broken and...

Another fundamental concern about MS is that it is experimental. Its ok for those that like to tinker and control their own destiny, but not a good commodity solution for the masses.

I would assume the same thing however i have already done this on multiple cars with no permanent modification to the wiring harnesses. One of my requirements when I built my original system was to not modify in any way the stock wiring harness as I had a really nice R.E.S. wiring harness that I paid to much money for many years ago.

d-jet triggers the injectors on the hot side with a fixed ground, megasquirt is the opposite and uses fixed power while switching the ground. The only problem is that the d-jet injector grounds terminate at the engine case and not at the ECU. The solution I came up with was to just run the ground wires from the 2 injector banks back to the ECU. This is probably the most non-stock aspect of the system but still really simple and does not modify the stock harness. My return wires are hidden under my harness but for someone really worried about a stealth install these could be run in the harness as well. EMI shielding may be an issue in some cars but it is not one I have came across yet and I have not seen any megasquirt installs that address this. I do shield the wire that gets the tach signal from the coil however I have not noticed a difference with or without the shielding on my installs.

I have seen your work though and believe your electrical engineering experience most likely goes WAY beyond mine, so I would appreciate any input on the mater.


As far as MS being experimental, I consider it experimental only due to the fact that you can experiment with it as it is an open project. In many ways I see this as a good thing as it allows for wider development and problem identification. The 2.2 boards have been “experimental” for almost 10 years now, and despite the fact that it was intended to be a DIY system, it was still designed by professionals. Is any other PEFI system on a 914 less experimental?

Even with all the real world megasquirt installs that have been done, as this board is a variation of a 2.2 board it will receive a LOT of testing before I would be comfortable releasing it to anyone.