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Discussion Starter · #1 ·
Anyone having and issue with the accuracy of the fuel level sensor?

Seems like the fuel level seems to be displayed incorrectly when the bike is partly refilled not from empty.

After riding aggressively in the mountains, I had a lot of gas left in the tank and the fuel light still came on.

Common issue?
 

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Discussion Starter · #3 ·
I've had some issues as well but my dealer is working to get them resolved

1) CSS leak - just repaired and am checking if leak still is occuring

2) brake light switch failure. Backordered part. Just arrived and being installed today
 

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Read your manual. It explains the delay in updating the fuel level. Letting the bike sit for 2 minutes will usually get you an accurate reading.
 

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Discussion Starter · #7 ·
Read your manual. It explains the delay in updating the fuel level. Letting the bike sit for 2 minutes will usually get you an accurate reading.
Challenge accepted. I read both the refueling section and the one where it notes 2 minutes off the side stand to obtain accuracy of the level sensor.

I think you're missing the context of my issue. I'm not concerned about the gauge on the instrument clusterreading accurate after I fill up, I'm concerned about it reading fuel level low too early. The section you referenced actually alludes to a delay in reporting the fuel level to prevent a false alarm and early low fuel level indication.

What I'm seeing is the opposite.
 

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That would be more favourable than my issue of running out of fuel when the dash says 40km remaining.
 

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I wonder how aggressive your riding was in the mountains?

I think the fuel light is triggered when the bike's calculated remaining range drops below some threshold of distance - i.e. number of miles / kilometres - it's not directly related to the number of bars on the display.

ICU computers consider some window of time / distance / fuel consumption to base its calculation on. This could be the last 30 miles, last 20 minutes of runtime, last few litres of fuel, or some combination of those - it's impossible to know without seeing the software source code. In any case it's based on how you are using fuel while riding.

So if you were hooning it at WOT for much of the time in the mountains then you should expect the range light to come on when there are more bars of fuel displayed in the guage than if you were riding with small throttle openings for more of the time.

This averaged calculation of range / fuel remaining will increase as you fill the calculation window with more distance at smaller throttle openings.

Hope this makes sense.
 

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I normally get about 140-150 miles before the fuel warning comes on. If I fill up about then, it is typically about 2.8 gallons (US). I have gone as far as 190 miles on a tank. I took 3.3 gallons but I don't think I had if totally filled up as the pump was a pain. Based on my bike, fuel each bar is about 20 miles of riding on the fuel gauge.

For reference a lot of my time is spent cruising at 80 mph or faster. That seems to be the general flow of traffic around me. Usually a tank will have a few runs up into the triple digit speed range as well.
 

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Discussion Starter · #11 ·
I wonder how aggressive your riding was in the mountains?

I think the fuel light is triggered when the bike's calculated remaining range drops below some threshold of distance - i.e. number of miles / kilometres - it's not directly related to the number of bars on the display.

ICU computers consider some window of time / distance / fuel consumption to base its calculation on. This could be the last 30 miles, last 20 minutes of runtime, last few litres of fuel, or some combination of those - it's impossible to know without seeing the software source code. In any case it's based on how you are using fuel while riding.

So if you were hooning it at WOT for much of the time in the mountains then you should expect the range light to come on when there are more bars of fuel displayed in the guage than if you were riding with small throttle openings for more of the time.

This averaged calculation of range / fuel remaining will increase as you fill the calculation window with more distance at smaller throttle openings.

Hope this makes sense.
I hoping you're right. I was also wondering if the calculation algorithm is creating the low level signal and not just the actual fuel level. That would be kind of dumb in my opinion. I'll need to test this out but its really hard to not ride this bike like a hooligan for an tank's worth of gas :LOL:

To answer your question, I tend to ride REALLY aggressive in the mountains. Cant get by trackday fix because of COVID..
 

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The level (number of bars) is measured directly from the fuel level sensor in the tank - it's a metal tube (that probably has an electrical capacitor inside it spread over its length) with electrical connectors on the tank bottom. There's some smoothing in software to stop the reading flickering between bars as fuel moves around but unless it's defective it should be accurate enough.

If you fill up from empty, turn the ignition on (without starting the engine), retract the side-stand and wait two minutes the gauge will show full - it's nothing fancy.

The fuel usage is measured very accurately by the ECU - it has to as it has to decide how long the injectors stay open on each charge stroke. This is then used to calculate a fuel usage rate and combined with the knowledge of how much is in the tank can estimate what the remaining range should be.
 

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Discussion Starter · #13 ·
The level (number of bars) is measured directly from the fuel level sensor in the tank - it's a metal tube (that probably has an electrical capacitor inside it spread over its length) with electrical connectors on the tank bottom. There's some smoothing in software to stop the reading flickering between bars as fuel moves around but unless it's defective it should be accurate enough.

If you fill up from empty, turn the ignition on (without starting the engine), retract the side-stand and wait two minutes the gauge will show full - it's nothing fancy.

The fuel usage is measured very accurately by the ECU - it has to as it has to decide how long the injectors stay open on each charge stroke. This is then used to calculate a fuel usage rate and combined with the knowledge of how much is in the tank can estimate what the remaining range should be.
I think what I need is more info like wavshrdr provided. Specifically when the empty light comes on, how much was filled up after. That will be the gauge I will utilize to establish if I have an issue or not.
 

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Discussion Starter · #15 ·
How much fuel you can fit in when the light comes on depends on how you've been riding it.
Is this written in the manual somewhere and I missed it? Please clarify your source. This goes contrary to every shred of common sense present in a design.

I certainly hope the KTM engineers weren't stupid enough to approach it this way.
 

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Last week I hit orange warning on the grid for low fuel, rode another 30 miles mostly in 5th gear at speed and then close to my destination grid changed single slanted orange bar.. Checked tank and maybe quart of fuel left in tank. Seems pretty accurate
 

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Just to add a data input for the range indicator. So far it has been spot on with a small buffer. I'd say at best, when it says I have 30 miles to empty, it is pretty darn close at my current fuel usage rate. Now if I were to speed it up a bit, it will adjust. I normally don't ever want to run it empty as not good for the fuel pump. Don't know on this bike, but on some others I've owned, it has been in the tank, and it is often cooled by the fuel. So generally I just gas up when down to 2 bars.

I wish the gauge were much more granular like on my Ducatis. On my xDiavel it is a very fine resolution for the little bar graph and I feel like I can almost see the ounce running through it. You can pretty much tell if you are at about 40% or 35% left without much issue. On my KTM and BMWs you have a big bar that has to drop before you know where you are really at. Although at least on my BMW, if I am using their navigator, I can get an actual percentage left. Then again on one of them, the max range left it will show is 155 miles. I can ride a 100 miles and it will show 155 miles left. How stupid is that? At least on my 890, it is pretty darn accurate and typically starts off anywhere from 170-190 miles left for the range estimation. I still wish they had put a bigger tank on the 790/890.
 

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Today I got 265 km when the light came on, then filled up exactly 12 liters at 290 km. The trip computer stated 3.8L/100km.

This was all mountain pass riding between 80 and 100 km/h. motorways return really bad fuel economy with this bike.
 

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Discussion Starter · #19 ·
Did a quick analysis with a full tank and 95% highway riding. I got 111 miles before the gas symbol popped up on my dash. Fortunately, it popped us just as I reached my driveway at home.
I had a gas container ready with gas filled to the 20 liter mark which I emptied down exactly to the 3.5 gallon mark.

Doing the appropriate metric to imperial conversions and knowing the specified capacity of the tank from the owner's manual, I was able to calculate 1.9 gallons left. That's a huge difference from the 2.8 noted above and is close to half a tank!

Doesnt seem right.

5240
 
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