Fuel Management Guage Wiring for GPS.. help!!

[<Kyle>]

Trying to hook uo my Yamaha fuel mgmt guage to my GPS (Garmin 168 Sounder) so I can do real-time MPG info. Problem is, I can't find the wiring info from anybody!! Where I stand now is I've spliced into a white wire that originally went into the Yamaha speedometer as a 3 wire harness exiting the fuel mgmt guage (other 2 wires in this harness are black, black/red). I was told the white was data positive. I've also switched DIPs 5 and 6 correctly for GPS. Any other thoughts why this isn't working? Do I need a data "ground"?? I left the black and black/red still hooked up to the speedometer. Thanks for any help!! Kyle

[<boats.net>]

The white wire needs to be connected to the NMEA 0183 output lead of the GPS. Do Not Use Red and Black wires.

[<Hamfisted>]

The brown wire coming from your Garmin is the NMEA output wire.

Mike

[<Kyle>]

The brown wire from the Garmin is data IN; the blue wire is data OUT. Just wondering if anyone has already successfully connected a Garmin to the Yamaha guage via NMEA successfully. I don't even know what versions of NMEA 183 the Yamaha supports. I believe my Garmin is outputting NMEA 183 ver. 2.0.

[<Hamfisted>]

You're trying to tell your Garmin how much fuel per hour you are burning, correct? So you want to hook up the white wire FROM the FMS to the Brown wire of the Garmin....


Mike

[<boats.net>]

Mike and Kyle

Actually the Fuel Management Gauge that needs the signal. The Fuel Management needs a signal for the speed of boat from the speedometer or GPS to compute the GPH. You can not hook to both Speedo and GPS. The FMS needs to be hooked to output of GPS and disconnect all the wires from speedo

[<Hamfisted>]

Actually Boats.net the Garmin GPS needs the output from the Yamaha FMS to tell you fuel burn per leg of a planned route, or just gallons per leg, miles per gallon or any other fuel/distance calculation you want. The Yamaha FMS figures GPH with a simple internal clock that runs anytime power is applied to the FMS system and measures fuelflow with it's inline sensor and divides that with it's internal clock and shows you GPH. You have to cut the little flat plug off and only use the white wire, tape or seal off the red and black wire. The white wire is the NMEA output lead that goes to the GPS. On my Garmin 235 the white wire is attached to the brown wire from the GPS and works fine. Hope this helps.

Mike

[<Kyle>]

I'm trying to use the NMEA OUTPUT from the Garmin 168 to feed speed data to the Yamaha FMS. I didn't even realize that the Yamaha FMS would output fuel data. Is fuel flow even sentenced in NMEA code? If so, wow! Still don't think I'd use that info. exported from the guage. The blue wire from the garmin is currently successfully outputting NMEA to my raytheon radar and Furuno sounder. I've also spliced the white wire from the Yamaha FMS guage into this mix but doesn't seem to give speed data for the MPG calc. Dip Switches 5 and 6 are good I think (5 up, 6 down). Thanks guys!

[<MDT>]

Kyle,
Did you get this to all work out? I have the exact same question and have been fighting it for a year so so. I have the Raymarine RL70CL with GPS and am trying to get it to talk to the Yam FMS. The one combination of connections that I have not tired is just the Blue wire from Chartplotter connected to White wire to FMS. I have always had a gnd or shield connected. I gather that these are to be left taped up.
Thanks,
MDT
Seattle

[COJones]

I have both the speed multifunction gauge and the fuel mangemant gauge and I can't get the MPG to calculate in the FMS. Can someone place post the dip switch options for the fuel man****nt gauge. It would be much appriciated. If I can't get this to work, I will try to run the NMEA out from a Gramin to the white wire in the FMS. BTW: does anyone have the pin-out for the PS/2 connector on the FMS? Any information work help and I will be more than happy to share my results. Thanks David

[Poorsche]

I have both the speed multifunction gauge and the fuel mangemant gauge and I can't get the MPG to calculate in the FMS. Can someone place post the dip switch options for the fuel man****nt gauge. It would be much appriciated. If I can't get this to work, I will try to run the NMEA out from a Gramin to the white wire in the FMS. BTW: does anyone have the pin-out for the PS/2 connector on the FMS? Any information work help and I will be more than happy to share my results. Thanks David

Check out this infor from boats.net--I'm having similar problem.

The GPS and Speedometer will need to share the same ground in order to work properly, you might try to move the ground wire from speedo to same ground terminal as GPS.


NMEA terminology about wires and data signals is not standard and it's a real PITA to interconnect different devices !!!

[Freddy]

I did the same thing on my last boat, a 2002.
The white wire of that specific harness gets connected to the Nema OUTPUT of your Garmin and the other wires of that specific harness are not connected and taped off. Set the dip switches and all should work. I am assuming the fuel management gauge is a separate gauge from the speed gauge. The GPS input will supply the speed to the the fuel gauge only. The speed gauge will still recieve its input from the Yamaha engine. My old boat consisted of a Garmin 167C, Raymarine R70 radar and Furuno sonar.