diyMEFI -> tunable, upgradeable ECU that you can build yourself

[mattmon]

Hey River Dave's, I'm mattmon.

Over the years, this place has been helpful to me in doing random boat repairs, but always as an outsider looking in haha.
Today's the day I decided to register so I could show off a project I've been working on... and maybe ask for a little help!

My project is called diyMEFI. It's an open source ECU that is pin compatible with MEFI1/2.

Compared to the original MEFI units, It offers the possibility of improved timing resolution and sequential port injection.
It can also just be used as a plug and play replacement.

You can build it yourself for less than a hundred bucks.

Here's a link to the malibucrew thread keeping track of my progress. Also, here's where you can find my source files.

Why am I posting here?
I usually boat in Parker and Havasu and would like to find one or more local people who want to build and tune one of these!
Anybody interested? I'll mail you a PCB!

 

[Jonas Grumby]

nothing for mefi3? I want to do the holly, just to get the soot of the transom. But $2200 for parts alone suck.

 

[mattmon]

Started with mefi2 bc that's what I have.
Mefi3 looks almost identical in terms of capability.

The mechanicals are a little different.

Wouldn't be hard to respin the board with different connectors and pin out.

 

[mattyc]

Hey River Dave's, I'm mattmon.

Over the years, this place has been helpful to me in doing random boat repairs, but always as an outsider looking in haha.
Today's the day I decided to register so I could show off a project I've been working on... and maybe ask for a little help!

My project is called diyMEFI. It's an open source ECU that is pin compatible with MEFI1/2.

Compared to the original MEFI units, It offers the possibility of improved timing resolution and sequential port injection.
It can also just be used as a plug and play replacement.

You can build it yourself for less than a hundred bucks.

Here's a link to the malibucrew thread keeping track of my progress. Also, here's where you can find my source files.

Why am I posting here?
I usually boat in Parker and Havasu and would like to find one or more local people who want to build and tune one of these!
Anybody interested? I'll mail you a PCB!

View attachment 1422321

Interesting, I dont have use for 1 and 2 but am curious to see what comes of this.

 

[DaveH]

Hey River Dave's, I'm mattmon.

Over the years, this place has been helpful to me in doing random boat repairs, but always as an outsider looking in haha.
Today's the day I decided to register so I could show off a project I've been working on... and maybe ask for a little help!

My project is called diyMEFI. It's an open source ECU that is pin compatible with MEFI1/2.

Compared to the original MEFI units, It offers the possibility of improved timing resolution and sequential port injection.
It can also just be used as a plug and play replacement.

You can build it yourself for less than a hundred bucks.

Here's a link to the malibucrew thread keeping track of my progress. Also, here's where you can find my source files.

Why am I posting here?
I usually boat in Parker and Havasu and would like to find one or more local people who want to build and tune one of these!
Anybody interested? I'll mail you a PCB!

View attachment 1422321

not to rain on your parade, but what you are building is very similar to how megasquirt got started.

this is fine for the person who is VERY savvy and electrically and code inclined. but the reality is most here with expensive boats and engines want rock solid reliability and not some Frankenstein box that is not commercially supported.

its no secret the mefi boxes are obsolete and having been around a LONG time......a plug and play replacement with updated tuning capacities would be welocmed by the boating world.

but i dont think the vast majority of the boating population is interested in a home built ECU to put their trust in......nice idea though...build something robust and well tested with bug free software interface and i would bet you would sell many of them.

 

[Racey]

Is this Arduino microprocessor based? I remember years back someone hard started a DIY EFI code project based on Arduino hardware and programming environment.

Very cool project, quite an undertaking. As someone that has done a fair amount of embedded programming this is a good way to appreciate how much work goes into making these systems function properly and be user friendly.

 

[STV_Keith]

I'll second what Dave said. I'm in the powersports industry...work for a company call Dynojet which offers a product for motorcycles, ATV's, etc called the Power Commander. Being a boat enthusiast, I had the company build "CMD - Combustion Management Devices" for a few years. We went to some boat shows, worked with vendors, etc. The unit plugged in to the injectors and took over control of fueling since most of these engines seem to run rich in stock form. We also had a wideband kit that would autotune the map (closed loop feedback on the WBO2). The 8-cylinder MEFI kit sold for $599 and the dual channel wideband add on was another $399. Here in the US, we had very few sales. It was more popular overseas, Germany specifically. We offered it for quite a few applications as well, as a plug and play solution with factory connectors. Good software with a proven UI.

In the end, I'd say do it because you want it, but I don't think you'll get much in the way of market penetration personally. Been down that road and it didn't yield much.

 

[mattmon]

To be clear, this is an open source project.

diyMEFI is hardware that is pin compatible with MEFI 1/2 that can run the speeduino firmware.

(Yes @Racey, nailed it!)

One benefit to this is that you can build it yourself from easy to use parts for a reasonable price.

Another is that the knowledge to do so isn't locked up behind a need for revenue or market penetration.

There's also a big community behind the software who are running it on everything from lawnmowers to race cars.

Speeduino and megasquirt are very similar. The biggest difference being that speeduino is truly open source - where megasquirt is not. They both utilize tuner studio, which is a fully featured and modern tuning application with auto tune, data logging, etc.

To be blunt, I created this hardware to run my own engine... because I can!

Anyone else is free to build, use, modify, or ignore this as they see fit. It won't rain on my parade one bit.

The intent of my post was to get it out there and maybe find some people interested in contributing tunes for the myriad different engine configurations to which MEFI was equipped.

I've already got the first one, for a 5.7 lt1 mpfi.



Edit:

@STV_Keith, your comparison seems a little apples/oranges. Power commander looks like a great product to modify and switch tunes, though it's not itself an ecu?

Diymefi replicates all the functionality of the original mefi unit, and then some.

Whether you just want a pnp replacement, or to build a fire breathing monster with sequential injection, boost control, digital dash, etc... diyMEFI + speeduino can do it.

 

[STV_Keith]

@STV_Keith, your comparison seems a little apples/oranges. Power commander looks like a great product to modify and switch tunes, though it's not itself an ecu?

Diymefi replicates all the functionality of the original mefi unit, and then some.

Whether you just want a pnp replacement, or to build a fire breathing monster with sequential injection, boost control, digital dash, etc... diyMEFI + speeduino can do it.

You are correct. My point was that if a PNP solution won't sell into this market, a DIY is likely to have less success IMO. That said, if you're doing it for you and the one or two other handy dudes that might do it, then go for it. It's always cool to have something that's one-off, especially if you built it yourself.