Scutty

I'm curious what is wrong with it.  I'll trade you code for you dead MMDC

Just to make sure we are on the same page, I did not replace my MMDC. I'm actually using data from it. I got rid of the gauges only.

1) this is totally feasible. Another guy here is working on a 1600 replacement. All the sensor interfaces should be the same. https://www.wakegarage.com/forums/topic/839-mdc-1600-plug-n-play-replacement/  the one interface that I have not worked on yet is the depth finder on these boats.

2)  Yes, lot of proprietary SW needed. The issue is the CAN data is based on an SAE specification that is copyright protected. Diagnostic messages that are not broadcast ( you need to poll for ) are proprietary to the engine manufacturer.  I would be violating their IP if I published it openly. However, there are lots and lots of site out there where people (like me)  have figured out what codes mean what and how to convert them.

3) I'll share all my code. Just PM me. I've given it to others here working on similar projects.  Happy to help as long as you promise to post your learning here for everyone's benefit and you don't use anything for commercial gain.

4) I'm actually trying to figure out how best to do DBW speed control now. Believe it or not the interface for Perfect Pass is 0-5V analog even for electronic throttle bodies.  I've hacked that interface and can manual adjust throttle settings but have not closed the loop yet. Zero Off is another matter. Zero Off only works with eControls ECMs (as far as I know) the ZO interface is proprietary. I built a black box data logger to isolate the speed control handshake but can't quite crack their message format yet. I hope to get back to this project over the summer.

I used a lot of open-source libraries but all the application level software is homebrew. If you go to Newhaven Display and FTDI web sites and look for EVE graphics you'll find lots of examples. Feel free to PM me.

And pinout info for the medallion gauges. My setup uses the MiniMMDC -7021. My gauges only have 4 pins. I understand that there are 5 pin gauges and they seem to be more common. I have not looked into the differences. If anyone has a 5 pin set up maybe you can add on here.

The connector coming out of the MDC is a Aptiv / Delphi GT -150 series. You can get them here:

This connector plugs directly into the back of the gauge. They are all the same since these gauges use a serial databus. Any connector can go to any gauge. If you have a spare like I did you could simply chop the connector off to tie into the arduino. I wanted to make this kit as plug in and reversible as possible. I found a mating 4 pin connector here:

You can find all the crimp terminals and other parts you need to make a complete set on this site.

Yellow -  Data - this is the serial data bus - active low, RS-232, transmit only, 9600 bps, 8N2

White/Red - 7 to 9V Power

Grey or Black - Ground

Blue - Nav Lights

Here is some additional pinout information on the CAN bus.

For this project I chose to tap into the standard OBD-M diagnostic port on most MEFI-5 and newer boats. There are other places to tap into the CAN bust but this was easiest for me.

Pin A - +12V

Pin B - GND

Pin C - CAN +

Pin D - CAN -

Pin E - no connect

Pin F - Speed control - tie to ground if you are using PP or Zoff

2007 Malibu rLxi, 340 Monsoon with a GM MEFI-5. I have no connections or dependencies on the Perfect Pass. (that'll be the next project)  I'm still hacking on the functionality but yes I added fuel used counter that accumulates up, fuel level counter that counts down. I set the current input manually. So when I add 10 gallons I go to the config screen and input how much fuel I added. Then it counts down from there until I zero everything or add more fuel to the counter. I also display instantaneous real-time fuel consumption to the main display. It's pretty cool to see how different conditions affect fuel consumption.

Quick update. I recently added native, Scangauge like, functionality to calculate fuel usage. It is ridiculously accurate. Add 5 gallons and watch it tick down in 0.1 gal increments.  Longer time accumulation time would be even more accurate since you have to calculate fuel usage per sample period based on instantaneous GPH. I'm using 30 sec update rate and it works great. The raw data is found in the 65500 J1939 CAN message. If you unpack the 8 data bytes look for:

Byte 1: must = 0x01  << there are multiple message types that use the same 65500 ID. This needs to bey "message 1"

Byte 4 and 5: This is where the raw GPH info is. Two bytes. The  5th byte is the high byte, 4th is the low byte. Then divide by 256

Quick update, so far so good. I've put a few hours on the boat, half dozen pulls, multiple heavy rain storms and some 90+ days baking on the lift. No issues. I was able to figure out a few more of the Medalion data packets.

My original gauges were run off a Medallion miniMMDC v3.4 702-00009-01.  This unit drives the analog gauges with a digital serial bus. The serial line is basically RS-232. Each "message" has an ID, data and check sum. There are 8 data messages that come out at different rates.

BE: RPM /4

4C: always zero, not used?

B2: Speed /20 (mph) (my boat uses a paddle wheel)

64: Oil Pressure (psi)

A8: Battery Volts /20

6E: Coolant Temp (deg F)

60: Fuel level /2 (%)

E9:Depth/10 (ft), Air Temp/10 (degF), Lake Temp/10 (deg F), Oil/10 (psi), Volts/10, Engine Hours/10

Also remember if you make a connector to pull the CAN data off the engine diagnostic port and you want to run a speed controller (i.e. perfect pass) remember to add the jumper from pin B to F. This is an important one I forgot.

6-Pin ECM CAN diagnostic connector:

Pin A: 12V

Pin B: GND

Pin C: CAN-Hi

Pin D: CAN-Lo

Pin E:  N/C

Pin F:  Connect to ground to use speed controller

Anything that is pre-packaged with any meaningful water resistance spec is going to be at a very different price point. As it is this raw display is >$150. I focused on good high brightness and operating temperature range. This one is good from -20 to  70C and 90% RH. It also has good specs for shock, vibration and esd. If you look at the CAD file I posted of the aluminum bezel you can see the screen sits in a recess and overlaps the glass. I added a thin foam gasket so the bezel seals tight against the glass. On the back I made a plastic cover that is also sealed to the back of the bezel. The whole set up is fairly well protected from the rain the way this dash is built from the factory. I'll let you know how I make out this summer.

That sounds like a great project. That's a big bump going from MEFI 4 to 5. I'm sure the group here would love to see a post on this conversion. I'd like to learn more about how you went about it, cost, time etc.

Here are the off-the-shelf parts.  I probably have another $100-$150 in materials for the aluminum bezel and other misc parts.

Paying up for a high brightness, transflective, sunlight readable display is worth the $.

https://amzn.to/3i1wLMB

The dash pieces were probably the hardest and most time consuming part of this project but it's worth it. The formed vinyl -look plastic they use at the factory looks cheap IMO and doesn't match the rest of the boat. I pulled everything out of the parts, all the gauges, steering column, speakers, throttle...everything. Once I had the raw parts I peeled off the covering and the original foam to get all the way down to the raw plastic. I used 3M #80 Rubber and vinyl spray adhesive to glue down 1/4 foam. Here is a link: https://www.miamicorp.com/products/FOAM/CLOSED-CELL/LANDAU FOAM.aspx
This foam can be shaped and sanded with a palm sander to feather in the edges. Sew up a new skin with new vinyl using the old skin as a pattern. Use the spray glue contact cement to glue the new skin in place. The factory uses a very flexible, formable vinyl for this. The heavy stuff you used for your seat doesn't form as easily. I needed to add a few tucks and a few more seams to make some of the tighter turns.

I'm actually thinking of doing mine over again. This was the first time I did something like this and there are a few mistakes that still piss me off. If get back around to it I'll post some more pics along the way. 

FWIW I have experimented with the SEM vinyl paint. It's not a bad product but the couple of parts I used it on for a previous boat project did not last. It started to fade and bleed through after the second season. Not worth it IMO.

A couple more sites maybe for the resource page: https://www.bakesonline.com/ and https://www.greatlakesskipper.com

For this project: electric heating elements to add heated drivers seat, new pullout heat vent tubes, new function specific switch covers (lights, music, seat heat etc)

Also added this cool flip up front nav light: https://www.bakesonline.com/bow-light-malibu-boats-roll-over-hidden-bow-light.html