If the flow sensor is connected by NMEA 2000, and the NMEA 2000 is out/not functional then it would be impossible for the data to arrive at the GP1971F. If no data arrives, it will not show data that it isn't provided.
Im looking to upgrade my Yamaha fuel management system and if I can replace the fuel flow sending units with something that is nema 2000 and send it to the 1971 to eliminate the Yamaha gauge then that is what I would like to do. I just need to find out if I get a fuel flow sending unit that is nema 2000 and hook it to the 1971 if it will show up. I have twin OX66's with 2 bad fuel management sending units and redoing my dash. If the 1971 will not show fuel flow then I will just replace the Yamaha ones with new ones and replace the gauge.
If the flow sensor is connected by NMEA 2000, and the NMEA 2000 is out/not functional then it would be impossible for the data to arrive at the GP1971F. If no data arrives, it will not show data that it isn't provided.