Multi-Function gauge fuel level v. Garmin fuel level display

[Hogfish823]

OK -- I received delivery of my new boat and need some help with the gauges.
Brand new Suzuki multi function gauges (Part 34200-96L2). Brand new Garmin 1242. Everything is supposed to be synced together and for the most part it is. My problem is with the fuel level being displayed on the Suzuki gauge.
Boat Gas tank is 150 gallons
Suzuki Gauge displays 1/4 of a tank.
Garmin Fuel level displays 3/4 of a tank.
I contacted the dealer, which is 500 miles away so taking the boat back for fix is out of the question, and they said they put in approx. 35 gallons of fuel.
I had fuel delivered and they put in 92 gallons.
So, 92 plus 35 is 127 gallons thus I tend to believe the fuel level on the Garmin is accurate since the tank is 150 gallons.

So.... How do I get the Suzuki multi function gauge to display the correct level?

[Handsomerob1980]

Tell it how many Gallons have been Added. I believe the Suzuki gauge works off of how much fuel is used and isn't actually reading the tank level. So tell it you you added 92 Gallons and it should match up. I believe that every time you add fuel or "Fill up" you will need to tell the gauge you did so. I could be wrong and your boat may have a nmea 2000 fuel level sender. Not sure on the specifics of your boat.

[Moonlighter]

The fuel level showing on the bar graph on the Suzuki SMG4 gauge is drawn from electrical connection to the tank sender unit. So in the same way as an analogue gauge gets an electrical signal from the tank sender unit (ohms) then so does the SMG4. As the ohms from the sender unit change as the fuel level changes, this makes the gauge change.

If I recall correctly, there are 2 settings in the initial settings on the gauge for tank senders, because the Euro tank senders use different ohm settings to US.

So I suggest having a look in the gauge menu, initial settings, and you should find fuel gauge settings there. If unsure, call the dealer and ask them whether this setting needs to be changed and how to do it.

The other thing is that generally it is not possible to successfully run 2 x gauges from 1 tank sender unit. Ohms get messed up. So check that too.

Garmins have their own internal fuel data memory, so the fuel level in the Garmin may be a calculated fuel level based on fuel burn data it gets from the Suzuki. So while it gets the burn data from the Suzuki, the x gallons it says were burnt and are remaining are calculations done in the Garmin. You will find that if you reset fuel used to zero in the Suzuki, fuel used wont change in the Garmin and it has to be reset separately.

The reply from the previous poster is not correct. SMG4 does not work like C-10 and its gauge is indeed reading signals from the tank sender unit. You cannot tell SMG4 that x gallons were added, as you no doubt are aware, the only thing you can do when refuelling is reset fuel used to zero.

[Moonlighter]

The post by Rob is incorrect. The SMG4 gauge you have doesnt work that way. Unfortunately this forum has marked my complete reply posted earlier as possible spam for some reason so it will take a day or two to be fixed. Wait till its up.

[Handsomerob1980]

The post by Rob is incorrect. The SMG4 gauge you have doesnt work that way. Unfortunately this forum has marked my complete reply posted earlier as possible spam for some reason so it will take a day or two to be fixed. Wait till its up.

Thanks for Straightening things up, I was going off what I know or think I know. Clearly you are well in the know.

[Moonlighter]

Thanks for Straightening things up, I was going off what I know or think I know. Clearly you are well in the know.

No worries, Rob

Its easy to confuse the Suzuki C-10 digital gauge and the OeM Suzuki SMG4, they do look quite similar, but are in fact completely different in the way they operate, the way they connect to the engines, and how they manage fuel data and refuelling.

Luckily Hogfish mentioned the part number of his gauges in his post so I knew he was talking about SMG4. They are relatively new to the USA being released there early 2019/20 if I recall correctly.

Here is a link to a Aussie video released back in 2015 when SMG4 was first released to everywhere except the USA. Hope you enjoy.

https://www.youtube.com/watch?v=YfaAR4P1Fgk

[Zukster90]

The never ending fuel level discussion. I am new to the forum and apologize if I am posting or asking incorrectly. I've searched, bi not able to find my issues. It is disappointing that a $600 guage is so hard to make functional with a simple and time proven fuel sender. I too am struggling. Inaccurate readings to begin with. Pulled sender and checked the resistance at different levels. Numbers are within range. Calibrated in the custom mode by simply positioning the float at the appropriate levels and setting on the SMG4. I know it isn't perfect, but well within an acceptable range. Issue now is that the fuel level shown on the fuel page is no where close to the reading on the all items display page.

[Zukster90]

Fuel level issues on the SMG4

[Moonlighter]

Did you read the earlier replies re the gauge initial settings?

other than that, if they are physically connected correctly, and calibrated correctly, they will work correctly. Rarely hear of issues, when we do the gauge sender wiring is #1 problem and gauge setup is #2.

Here is a link to the SMG4 installation manual. Its a few years old but should be the same in mist respects to the current version. Suggest you got thru it carefully and ensure the physical wiring setup is correct and then the gauge settings and calibration are done correctly.

https://www.dropbox.com/s/u2fa08g7nw...glish.pdf?dl=0

[Zukster90]

Thanks for your response. I've read a lot of your posts and they have been very informative. I did download the page you referred to. I had a boat electronics technician go over it with me. He suggested to pull all new wire to take that out of the equation. Simple enough. 25 yr. old wire probably has a little corrosion in the strands. Good place to start. Thanks again

[Moonlighter]

Thanks for your response. I've read a lot of your posts and they have been very informative. I did download the page you referred to. I had a boat electronics technician go over it with me. He suggested to pull all new wire to take that out of the equation. Simple enough. 25 yr. old wire probably has a little corrosion in the strands. Good place to start. Thanks again

Im not sure what “wire” you are referring to. But yes, any old wiring can be less than optimal.

If its an old engine wiring harness being used on a new engine, almost certainly that will be the issue. The old harnesses pre about 2012 are not compatible.