Hi all, I'm a frequent visitor but have never posted. Sorry if this is not in the right place. I've been doing research on diagnostic scanners for my 2007 rlxi. I have an MEFI -5 ECM. There seems to be a lot of info here and on other forums for MEFI 1-4 but for newer ECMs everything seems to point to Rinda https://www.rinda.com . Their products look awesome but are too pricey for me and don't provide an open interface layer. I'm a DIY'er, non-professional, looking to do some basic diagnostics and maybe build some home brew digital gauges. I'm hoping to get a thread going to collaborate on and save info related to MEFI 5,6 and eControls.
I have no commercial interest in this project but I would like to recognize a few companies & websites who have a ton of great, open information and products: OBD Diagnostics https://obd2allinone.com/mefi5scan.asp , Copperhill Technologies https://copperhilltech.com/ Elm electronics https://www.elmelectronics.com/ , Bakes https://www.bakesonline.com/bakes-resource-library
Here's a start. I'm happy to share more if there is interest in this project.
MEFI-5 an newer (including Econtrols) use a CAN bus, 6-pin diagnostic connector, J-1939 29-bit / 250kbps CAN protocol
Connector parts and adapter cables can be purchased from OBD diagnostics
Most inexpensive OBD II scanners for cars use the ELM 327 chipset (or some derivative or knock off). These scanners can be reconfigured to use the J1939 protocol to read messages on the bus.
Inexpensive Arduino boards with a CAN interface from Copperhill can be quickly configured to read J1939 messages using their free code examples
The bad news: the magic decoder to translate raw CAN messages to meaningful human readable information is contained in a proprietary SAE standard
The good news: Boats are pretty simple and a lot of the important information is out there in manuals and other examples.
First I built a wifi black box "flight recorder". So far I've got an arduino due with CAN transceivers from copperhill streaming CAN messages to a raspberry pi zero. I can read things like throttle position, RPM, Coolant Temp, Oil pressure, engine hours etc. I can also pull any stored / pending DTCs (DM2 messages). The same thing can be done with an ELM 327 based scanner (https://www.scantool.net/obdlink-sx/) but instead of using their software for cars just connect to it with putty (any serial terminal emulator will work) on windows or linux.