Pumping Slowly

[bowtieguy]

pumping gas slowly, does it have FE benefits?

got the idea from Brucepick. anyway, in theory, pumping gas slowly prevents vapors from escaping resulting in more gas retained.

the first time i did this, my FE went down significantly. IF more gas is retained, this makes sense via more gal to divide into miles. next fillup would balance the #s right?

this IS what happened to me. got ~30mpg before the test w/ VERY favorable conditions. then, pumped slowly to~25. next fillup, again slowly, got 29+. both were less favorable, but VERY similar miles, w/ the only variation being my lower grill block. it came off during both "trips," the latter being repaired(replaced)permanently. oh yes, and one extra day to work(mostly hwy) on the 2nd. that can't be worth 4mpg tho.

this IS very preliminary, but what do you think?

[slurp812]

Originally Posted by bowtieguy

pumping gas slowly, does it have FE benefits?

got the idea from Brucepick. anyway, in theory, pumping gas slowly prevents vapors from escaping resulting in more gas retained.

at first, I thought I was on the wrong forum!

[skewbe]

It might be that pumping slower means the fuel foams up less and you can get more in the tank before it clicks off. Getting more gas in the tank would make it seem like you got worse mileage. Can't say for certain that is what is happening though as one tank isn't enough to go on.

[JanGeo]

Usually pumping slowly will get you more fuel from it leaking around the metering system in the pump - the amount of fuel vapors that come out of the tank while filling is next to nothing. Today when I got gas I usually pump slow for the last gallon into the tank because it foams up so much and when I did the pump did shut off then the gas over flowed - I still put in another $2.00 work of gas after it overflowed - sure wish there was a better way to get the gas in with it not spilling and still fill the tank up.

[bowtieguy]

it seems as tho more gas is making it into my tank. this is in observation of how much is pumped in relation to what the gauge reads.

again, it is very preliminary but, consider this: without exception, since adding mods(hypermiling), the gauge reads ~1/4 tank as i near 300miles. the last fillup was 341miles and the gauge read ~1/2.

i realize gauges are not perfectly accurate, but it is interesting. so, as testing continues, time will tell.

will try testing this on my wife's car as well. scangauge compatible
unfortunately, she doesn't drive as consistant miles as i do.