Wrong gas gauge reading

[wsaechao]

So here is the scenario...

I rarely use gasoline in my 2018 Honda Clarity so I try and keep little gas in the tank, but enough to where the gas light doesn't come on. This is to ensure that the gasoline doesn't sit in my tank and go bad.

The other day as i was driving on gasoline and the low gas light came on. So i went into a station and put 1 gallon in the tank. I turned on the car after refueling and noticed that the low gas light indicator was still on and the gas markers didn't move. This was odd to me considering that 1 gallon is 1/7 of the capacity of the tank so the gas markers should have ticked up a couple of ticks i would assume. I drove around a couple of days on electric and decided to put another 1 gallon in the tank (to get rid of the low gas light indicator). I added another 1 gallon and the gas gauge still didn't move! The range indicator stayed the same and the low gas light indicator was still on. I went into the station instantly and added 1 more gallon (3 total now) and NOW the gas gauge jumps to half full, the low gas light indicator turns off, and there was about 100 miles added to the range indicator...

I know my scenario is very specific, but has anyone experienced this issue (and have any resolution)???

 

[petteyg359]

No, because I like to keep records of MPG on my cars myself. The estimates of the computer in the vehicle are never right. You can't accurately measure your MPG when you don't *fill* up, because you don't know how much gas you used if you don't fill the tank back to the known fullness point of "full".

Can't think of what might cause it to not correctly gauge an extra gallon in the tank, though.

 

[Fast Eddie B]

I have found it takes a few minutes for the fuel gauge to recognize fuel added. This seems especially true if I just add a gallon or so to a nearly full tank, which I’ve done on occasion to test fuel consumption on a certain trip.

 

[Walt R]

I don't have this info for the Clarity (and I haven't driven mine enough yet), but on my Prius it was specifically documented somewhere that the gas gauge will not go up for less than ~3 gal of gas (on an 11-ish gal tank).

I surmise that this is just part of the fuel level averaging that is done for digital gas gauges. On an analog gauge no one probably noticed if the needle wavered a little with hills and such, but people notice when digital segments disappear and reappear (10 on the Prius, 20? on the Clarity), so I believe that the engineers have coded these digital gauges to never increase, except above some threshold which is a significant portion of the tank capacity.