Can't think straight about gas tank.

I can't think straight after reading your post

 

Gas pumps are all inaccurate to some degree, which is why its best to always use the same pump or at least the same gas station.

As for the "effect" of one fill at a wonky pump, it really doesn't make any difference in the long term Use Fuelly or some other tracking system to track fill-ups over the months. You've still used x gasoline over y miles, so it will average out. The only thing that screws the stats is if you pump gas onto the ground.

 

I refuel at three stations mostly. One station I refuel at typically allows more fuel before shutoff. It could be their sensor, the temperatures, or the slight downhill if I drive in a certain way. I've never actually tracked the particulars, but when I refuel there, my calculated milage is down more than the computed mileage. Unfortunately, I don't have the data to correlate the actual differences. My last tank showed the displayed mileage to be 2.5 mpg higher than calculated, while my other fills were closer to 1 mpg off. This last tank used was from one of the other stations, which appears to have led to the higher than normal discrepancy.

But we're talking about a difference of .6 gallons, so this is not remarkable.

 

Hey Brian, Some pump nozzle have a slight different curve so when you stick in your tank the flow hits the side and if any resistance it will shut the pump off. I usually pull the nozzle out about 3/4 inch to minimize this effect . Now most nozzles in the US you have to push the nozzle in to create a pressure seal, but I have never seen it in Canada. Also some vehicles have different curvature in their piping so pulling it out a bit doesn't always work. It is not an exact science .

 

I set the nozzle at the lower flow rate. That usually prevented premature shut-off.

 

I do both of the above to prevent the shutoff issue, do not insert fully and set to the lower flow rate. Works for me.

 

I only saw the issue in the cold winter. I'm surprised it pops up in NC

 

It seems to depend on the pump sensitivity to me and not necessarily the weather. After having this happen a couple of times I just automatically do the above and have not had any other issues.

 

I think you just got unlucky, got a pump with malfunctioning shut-off. I'd:

1. Notify the station manager. Basically so it gets fixed.

2. In future just pump gas normally. This was a one-off, not a common occurrence.

 

I had the same thing happen to me yesterday (went to a different petrol station) so pulled the nozzle out by about 2 cm and hold the trigger a little less tightly to lower the flow rate. In past 2 fills I was satisfied to stop after the second click, but this time I had to makes sure and it took about 5 clicks. No spills thank goodness. Yeah you can't be precise as there are a couple of factors we don't know. The pumps are probably variable in accuracy, and we fill up to "full" though we can't see how full. But choosing the same petrol station most of the time and making it a rule to fill up and stop after the second click (or third click if you choose) helps to make the average more accurate. Anyway 5.2 is what I am getting now.