Garmin fuel data settings on new GPS

Erin · 23 February 2011, 13:11

Can someone explain to me the Garmin 'Fuel' data on the 5008 GPS please. I have an N2K fuel level sender which is connected to the network and the Garmin correctly shows that the tank is presently 1/3 full. However, somewhere along the line of setting up the GPS it aksed for my tank size. I input this as 35 gallons, and whilst the GPS fuel gauge still shows 1/3 full the data bar on the nav screen shows that I have 35 gals remaining. I wish.

I know that the Garmin can use fuel usage from the engine to estimate the fuel amount remaining in my tank, but I don't need this with a calibrated N2K sender. It is obviously getting confused in its calculation. I have selected the correct options for using fuel sender not fuel flow for calculations, but it won't play ball.

Channel Ribs · 23 February 2011, 13:50

Eliminating the obvious.... Has there been an imperial/metric/US crossover?

Have you added more than two calibration points?

martini · 23 February 2011, 15:08

Could be like smartcraft which has different calibration methods.

With odd shaped tanks you can calibrate empty, 1/4 full, 1/2 full etc

Maybe the tank needs to have 35 gallons in it when you input the capacity

Channel Ribs · 23 February 2011, 15:13

Quote:

Originally Posted by martini

With odd shaped tanks you can calibrate empty, 1/4 full, 1/2 full etc

The Garmin one is quite clever, for odd shaped tanks you can put in several calibrations and can get a very accurate model of your tank.

Erin · 23 February 2011, 15:57

Any idea where in the menus the calibration option is for irregular shaped tanks?

Channel Ribs · 23 February 2011, 16:04

Device list, review, level calibration, add cal point.

Start with a known quantity, then add amounts measured not by gals/liters but by percentage of tank capacity. IIRC.

So as you have a 35g tank it might make sense to add 3.5g calibration quantities?

Channel Ribs · 23 February 2011, 16:15

I think the manual makes it clearer than my gibbering...

Calibrating the Fluid Level
To use the GFL 10 adapter, you must calibrate the fluid level of the tank that the adapter is associated with, using a minimum of two calibration points. The greater the number of fluid calibration points, the greater the accuracy of the reading on the fluid-level gauge.

1. Turn the boat ignition key to the On position (not Start).
2. From the NMEA 2000 Devices list, select the GFL 10 device.
3. Select: Level Calibration > Add Calibration Point.
4. Select the percentage of fluid currently in the tank, based on the total tank capacity.
5. Select Done.
6. Change the level of the fluid in the tank.
7. Select Add Calibration Point.
8. Select the percentage of fluid currently in the tank, based on the total tank capacity.
9. Select Done.
10. Repeat steps 6 through 9 to add additional, optional fluid-level calibration points.

Erin · 23 February 2011, 16:38

Ahhh, but I don't have a GFL 10, I've got an Offshore Systems NMEA200 sender. Purchased before the GFL 10 was even a twinkle in the Garmin Engineer's eye. Will see if I have a calibrate option for it nonetheless.

Channel Ribs · 23 February 2011, 16:45

Quote:

Originally Posted by Erin

Ahhh, but I don't have a GFL 10, I've got an Offshore Systems NMEA200 sender.

Aaaaah

Well, at least you saved thirty squids.

The calibration should be the same surely, as it is the plotter doing all the work? I have not installed the Offshore Sys version though, so I am going out on a limb.

Erin · 23 February 2011, 21:39

Just been out to have a look, and i can't find any calibrate option. It sees the Offshore Sys level nicely, but won't let me do anything with the data it recieves. Think I'll have to contact Garmin Support.

Erin · 24 February 2011, 21:18

Quick update. Been in contact with Garmin support. Still pending their final deliberations, but it looks like the Garmin can't get past its desire to calculate remaining fuel based on how much the engine says it has drunk. Looks to me like they might need a software tweak.

martini · 18 March 2011, 21:47

Probably irrelevant but there was a software tweak:

"Fixed an issue with MFDs unable to configure the GFL10 Tank Capacity."

I know you don't have a GFL10 but it might do something to yours?
Ver 5.9 onwards, don't know how old, you may well be ahead of that already

Also, I haven't got it with me but my new smartcraft manual goes into a fair bit of detail on tank calibration. I did have a quick read and it didn't sound that straightforward. As my 5012 is now showing a page full of fuel data same as yours, it may offer an insight

Erin · 18 March 2011, 22:35

I'm running the latest Garmin software but it doesn't help. Complex subject, and I still can't fathom whether it is the GPS that does the calibration of the fuel level or the fuel sender. I suspect the profile is stored in the sender so that it would apply to any MFD you had that was receiving the data. If that is the case, then as my sender is non-Garmin I don't think I have much chance of calibrating it. Still, it would be nice if it just used the sender for fuel level and not it's guestimate as to how much I've sent out the exhaust.

gotchiguy · 18 March 2011, 23:04

Quote:

Originally Posted by Erin

Any idea where in the menus the calibration option is for irregular shaped tanks?

'T'ain't that irregular

Erin · 24 March 2011, 14:34

Bit of further info in case anyone ever dregs this up in the future.

I spoke to OSUKL the mfr of my fuel level sender. Apparently the only N2K sentences a sender can output is volumetric percentage or level percentage. Any calculation to work out how many litres or gallons that relates to is done in the MFD or plotter. It sounds like Garmin have been in touch with OSUKL (possibly as a result of my enquiry) as they have sent them a sender for testing. Hopefully they'll amend their software.

There is only one way of calibrating the volumetric percentage reading from the sender and that is to connect it to an OSUKL display unit. However, as my tank is relatively linear, there doesn't seem much point in doing this.