Fuel Usage Calibration?

[thissenw]

Hello friends,
Fuel usage on my 2016 DF175 is off by a factor of 3. When I first installed the C10 gauges, fuel economy at 3500-4000 RPM was reported as 3.8 - 4.1 MPG. It’s now reported at 1.1 - 1.2 MPG. First fillup took 18 USG, but the system reported 55 USG used. Second fillup took 27 USG, but the system reported 76 USG used. Both times, I marked the tank as full, and selected the calibrate option to enter the actual fuel used. Any suggestion on how I can get fuel usage properly calibrated? Thanks.

N2K network nodes:
Suzuki Engine Monitor – software version 3.5.0-MZ1620C-B.1.0
Suzuki C10 Gauge – software version 1.1.50.2.126
Suzuki C10 Gauge – software version 1.1.50.2.126
Garmin 742xs GPSmap - software version 8.60

[artdf175]

I am thinking how I calibrated my usage, which is now very accurate..

somehow it is not calibrating correctly

I have a Lowrance HDS 9 after hitting the calibration, it gave back a percent correction figure..
Art..

Moonlighter may have some comments for you when he reads the post

[Moonlighter]

That is weird! All your Suzuki and C-10 software looks OK, but I have no idea about the Garmin.

Couple questions:

1. Are you saying that the fuel economy when it was all first installed was corrcet, and then suddenly changed?

2. If so, what was changed when it started tk go wrong??

3. Was the Garmin always on the network? Maybe take it off and see what happens?

The only other thing I can suggest is to go into the C-10 menu, network device list, unconfigure and reconfigure the Suzuki device. You will lose accumulated fuel data, but it is wrong anyway.

[thissenw]

1) The N2K net was a new install on a new-to-me boat. I have no idea what the actual MPG should have been but, based on previous boats, I thought it was reasonable.

2) It went wrong when I did the initial calibration after the first fillup. I saw the data was invalid, so I did a factory reset on both gauges. Then, the 2 fillups noted in my post show it made no difference.

3) The Garmin has always been on the network. Isn't it required to calculate MPG, by providing speed over the ground?

I see no place to reset reset the engine interface. I read somewhere that the fuel usage is actually stored there. Any ideas where this option might be?

Thanks.

[Harper]

I don't have the C-10 gauges, so I can't really address their part in this. But I do run a Garmin GPSMAP546s. It does provide your C-10 with GPS info, including groundspeed. The C-10 would use this to calculate MPG. But the Garmin also provides GPH info as read from the N2K via the engne interface. and it also has a page with MPG info. It cannot be used to calibrate the engine interface, but it does read all the data, same as the C-10 gauge.

So my question is......how are the readings on the Garmin? MPG and GPH?

[Moonlighter]

Yes you need a GpS source to calculate mpg. I was just wondering whether the Garmin may have caused a conflict. But if it was close to right when first installed, that wont be the issue.

It sounds like you may have messed up the first time when you tried to calibrate.

Read the last para of my previous post. That is where you should find the option to unconfigure and reconfigure the interface. That will basically reset it back to factory. If you see any option in that network device list under the Suzuki device that allows a factory reset on the interface, do that.

I am not familiar with the C-10 although I gather its menu system is similar to other Navico devices. If you cant find it, I suggest you talk to your Suzuki dealer and ask them to walk you theu how to do the unconfigure/reconfigure of the interface.

[thissenw]

Moonlighter,
I reset both trip and season fuel usage values to 0, filled the tank, marked the tank full, and spent a day on the water. I then refilled the tank with 15.25 USG. The system reported 37.8 USG used. Better than before, but still way off. So, I entered the actual refill value, and hit the calibrate option. Should this solve the problem? On the calibrate screen, there's a data element called K-val, with a value of 1.75. I saw mention of this element in another post. What is it?
Thanks so much for your help.

[Moonlighter]

Yes, you have stuffed up the refuel procedure. Thats not how to do it.

The K value represents the calibration factor. You cant change it. It is adjusted when the calibration is done. As it stands now, your K factor is corrupted

As Ive said a couple of times, you should go in and either unconfig and reconfig the Suzuki interface, or reset it to factory. That will rest the Kvalue back to factory settings. Conrinually Recalibrating without doing that will not solve the issue. Recalibrating is for "fine tuning".

The proper refuel process is to go into the refuel menu, select set to full, and execute that process. The system will then reset trip fuel used to zero. It will ask if you want to calibrate, and that is the only time you will enter an actual amount of fuel used.

You DO NOT reset trip fuel used separately. You can of course reset seasonal fuel used after the refuel process is completed.

So if you want to fix this, you need to listen to advice given and reset the interface to factory.

[thissenw]

Sometimes I'm a little dense. Found and performed unconfigure, configure, reset fuel usage, and set tank to full. Looks like it's reset. I'll see what shows up during my next trip out. Thanks again.

[Moonlighter]

Ok, good work.

I recommend you Use as much fuel as you can before refuelling, at least 1/3 of a tank. The more the better.

Then on the way home after using the boat, go back to the same gas station and refill at the same bowser - the idea is to have your boat at the exact same angle so when you refill the tank, it fills to the same level as last time it was filled.

This way the refuelling calibration prcess is more accurate.

I recommend calibrating if you are more than 3-4% out. Also, do not calibrate more than 3-4 times.

You could be lucky and it might be close to perfect out of the box. Ive seen many that are.

But if not, calibrate it and next time, if calibrating is done properly, it WILL be closer to 100% accurate.

Usually, 3-4 calibrations will get you so close to 100% accurate that the main variance from then on will be how full you fill the tank, the angle of the boat, and fuel loss due to evaporation from the tank. Yes, leaving the tank half empty for weeks on end will see a noticeable loss due to evaporation!

[thissenw]

Seeing 3.6 MPG at 4K RPM. About what I expected on a 23' boat with a 175. Got a 90 gallon tank. Probably use half before a fillup, and then see what shakes out. Thanks for your help.

[Moonlighter]

No problems.

Just some FYI's....

Fuel flow, mpg and fuel used are all derived from the same source, so calibrating will affect all of these figures.

Dont forget, every time you fill up, to reset to full!

You will know when this has been done because fuel used will reset itself to zero, and fuel remaining will reset itself to whatever your tank's capacity is (the figure you set when initially setting the network up).

Good luck, you should be on the right track now.

[thissenw]

First fill-up required 41.82 USG. System reported 40.09 USG used. Pretty close. I marked the tank full, entered the actual value, and hit the calibrate option. I think all is A-OK. Thanks.

[Moonlighter]

Looking good!!

Youre within 4% and a couple of calibrations will close the gap even further.

We use litres here and I am always within 0.5 litres on a 60-70 litre fill.

I set up my mates DF300 and last trip we used 280 litres, and it took 280.6 litres to fill. His boat is regularly this close.

You should be satisfied when you get it within 1%, then leave it alone.

[Isabarra]

Moonlighter I just had a maiden voyage in my new boat. We did around 320km over to sweers Island and up to bountiful islands in gulf of Carpentaria. My boat has a DF225 and boat has a 350 litre tank. Coming back up River 20km from Burketown we ran out of fuel and computer told me I had 50 litres left. How could I fix this. Boat was level at servo and completely full