Yamaha Fuel Mgt. Gauge

[reed123]

All: I have an issue with my Yamaha fuel management gauge, any help would be appreciated.

Problem: 2001, twin 200 HPDIs with original Yamaha multifunction gauges; Fuel mgt. gauge comes on fine when I turn the key, everything comes on, TTL, Econ, Sync, PS ect., showing the system check is fine. Now, when I crank the engines it may or may not show GPH & Total fuel burned, or it may start showing it, then 10 miles into the trip it stops. I bought the rig used in 04' and it has never shown the MPG or the Port / Stbd. icons while running. Is this optional? According to the manual if it is showing GPH, is should show everything else. So does it sound like the gauge itself, or one or both of the sending units? Is there a way I can test the gauge or sending unit? I hate to replace things that are not broken. Side note, the GPH & Total fuel burned worked fine until recently.

 

[rodbolt]

Re: Yamaha Fuel Mgt. Gauge

look at the bottom of the feul flow sensors. how many screws hold the sensor cap in place?
the MPG function has to be connected to the speedo or a GPS. look and see if it is.
if your running twins and the green and green/white wires are not hooked up correctly you wont get port and stbd.

 

[reed123]

Re: Yamaha Fuel Mgt. Gauge

Thanks, I'll check that in the morning. I can get to the back of the gauge pretty easy.
The sensors are another story.

 

[reed123]

Re: Yamaha Fuel Mgt. Gauge

OK, there are 2 screws on the bottom of each sensor, & the fuel mgt. gauge is connected to the speedometer. It looks like the green & grn/wht wires are connected, but will have to refer to the wiring diagram to make sure they are hooked up correctly. Like I said, the Port / Stbd feature & the MPG have never worked. When I press the "set" button to switch between P, S, or both, nothing happens.

 

[rodbolt]

Re: Yamaha Fuel Mgt. Gauge

fuel management,speedo and 1 tach must be wired so they all power up from 1 keyswitch.
the green white from the FMM must be attached to the port tach send and the green from the FMM goes to the stbd.
the sensor will have either 3 or 4 screws holding it together, three screws and its defective but yamaha will replace it for free.
MPG function requires either the speedo interface or the GPS interface or it simply cannot work.
2 screws hold the sensor to the hull, the sensor body will have either 3 or 4.

 

[reed123]

Re: Yamaha Fuel Mgt. Gauge

Thanks Rodbolt, I saw the 2 mounting screws, but can't see under the sensor. I felt under them and only felt 2 screws. I'll check again, would not be too hard to take one loose and flip it over. Tell me more about the free replacement deal, is that something a dealer would have to handle? Yes, everything powers up with the port keyswitch, I'll check the green & green/white connections too.

 

[reed123]

Re: Yamaha Fuel Mgt. Gauge

OK, while I don't recommend it, a fat old man CAN hang upside down for up to 3 minutes without passing out, that being said, there are 3 screws on the bottom of the fuel sensors. So now what Rodbolt?

 

[rodbolt]

Re: Yamaha Fuel Mgt. Gauge

so now you have to take the rig to an authorized Yamaha dealer and have the sensors replaced per bulliten o2000-013.
it was part of a safty recall program.
the 3 screw senders could leak.
bypass them or have them inspected by an authorized service center.
the original recall kit was a 90891 part number and is no longer avalible and the tech will have to call yamaha with the engine PID numbers.

 

[reed123]

Re: Yamaha Fuel Mgt. Gauge

Thanks Rodbolt, I did not know about the recall. I'll call the dealership tomorrow. At least I don't have to deal with now. I just hope they can get it back to me quickly.
Thanks again, your a wealth of knowledge.

 

[reed123]

Re: Yamaha Fuel Mgt. Gauge

OK, my bad, there are 4 screws, could not feel the one on the back corner. Anyway, called the dealer, ran the ser. #s on both engines, and found out this recall was done on my boat back in 2001. I still think the problem is the sensors, just wish there was a way to know for sure before spending $500.00 on new sensors.

 

[rodbolt]

Re: Yamaha Fuel Mgt. Gauge

other than carefully checking for corroded connections there isnt much trouble shooting information on the flow sensors.
but to get MPG function it MUST be interfaced with either the speedo OR a GPS.
to get the port and stbd icons it MUST be wired correctly.
speedo and FMM must turn on from the same key switch, the green white wire from the FMM must go to the port tach, the green to the stbd.

 

[reed123]

Re: Yamaha Fuel Mgt. Gauge

Thanks Rodbolt, everything "looks" fine with the sensors, but like you said, no way to test them, so I guess I'll take a $500.00 shot in the dark and replace both sensors. Hopefully that will solve all mt FMM problems. The green / White & Green wires are correct, guess that part is the gauge. Oh well, never had MPG, so I don't really miss it.

 

[reed123]

Re: Yamaha Fuel Mgt. Gauge

Update - It looks like 9 years of running E-10 fuel ate the plastic paddle wheels out of the sensors. New sensors are in and all is working fine. Still don't get MPG but that must be the gauge itself. I can live with GPH & TTL fuel burned. Thanks for all the input, time to go fishing.

 

[rodbolt]

Re: Yamaha Fuel Mgt. Gauge

until and unless you buy and install the speedometer to FMM or GPS to FMM interface cable it will NEVER give MPG.

 

[reed123]

Re: Yamaha Fuel Mgt. Gauge

Thanks Rodbolt, I do have the single lead cable installed from the speedometer to the FMM. Part # 6Y5-87122-S0-00, it just does not give me a reading when I push the "Set" button to go to MPG. Everything else works fine.

 

[rodbolt]

Re: Yamaha Fuel Mgt. Gauge

let me research it a bit.
the FMM dip switchs also must be set correctly.

 

[reed123]

Re: Yamaha Fuel Mgt. Gauge

Yep, thought of that too, all dip switches are correct, per the manual.