Connecting your car’s diagnostic system to your boat’s network might sound like a leap, but with the increasing interconnectedness of vehicle systems, exploring the possibilities of bridging Obdii To Nmea 2000 is a relevant pursuit. Specifically, for those using Holley EFI systems, the question arises: can their CANbus capabilities be leveraged for such a conversion?
According to Holley’s documentation, their harnesses do indeed come equipped with a CANbus communication connector. As stated in their manual:
All harnesses have a CANbus communications connector. This is used to communicate with CANbus devices, such as the Avenger Handheld tuning module or the 5.7” Touch Screen LCD. If these devices or any other CANbus device is not being used, there is no need to do anything with this connector.
A24 – CAN Lo (Pin B)
A32 – CAN Hi (Pin A)
Alt text: Diagram of an OBDII connector highlighting CAN High and CAN Low pins, essential for OBDII to NMEA 2000 conversion discussion.
This clearly indicates the presence of CANbus hardware within Holley EFI systems, primarily intended for their own devices. However, the potential for broader applications remains a question. An older forum post from 2010 highlights someone else’s inquiry into a similar NMEA conversion. The response they reportedly received from Holley suggested that these CANbus connections were solely for the designated Holley devices and not for general purpose use.
Despite this, practically exploring the CANbus output is worthwhile. A straightforward approach involves utilizing the CAN Hi (Pin A32) and CAN Lo (Pin A24) connections. By running a twisted wire pair to these pins and connecting them to a salvaged OBD-II connector from a vehicle, you can create a readily accessible port. Adding power and ground to this OBD-II connector would then enable any standard laptop adapter or scan tool to interface with the system.
The underlying principle here is that CANbus, much like Ethernet for automotive applications, is designed for data communication. If Holley employs a standard communication protocol – a reasonable assumption – then connecting an OBD-II reader should allow access to standard SAE PID outputs. This would include crucial engine parameters like RPM and TPS, among others. Successfully reading standard OBD-II data from the Holley CANbus would be a critical step in determining the feasibility of a more complex NMEA 2000 adapter implementation.
For those looking to experiment, Holley offers plug-in CANbus cable extensions, available in various lengths:
- 1 foot extension – Part Number 15663NOS
- 4 foot extension – Part Number 15665NOS
- 8 foot extension – Part Number 15666NOS
- 12 foot extension – Part Number 15644NOS
In conclusion, while Holley’s official stance and past responses suggest limitations on their CANbus connector’s broader usage beyond their own devices, practical testing with an OBD-II reader presents a viable path to investigate its potential for applications like OBDII to NMEA 2000 conversion. Successfully accessing standard OBD-II data would pave the way for further exploration into adapting this data for NMEA 2000 networks.
