F150 Ecoboost Forum banner
1 - 20 of 44 Posts

·
Registered
Joined
·
21 Posts
Discussion Starter · #1 ·
More stations than you realize have gas pumps that cheat you maybe 5 to 10% every time you fill up. I always reset my "gallons used" computer every time I fill up.

I discovered that several places where I have been filling up (Shell and about 4cents cheaper) have been slightly cheating me, according to the gallons used computer. The pump would indicate I put in 20 gallons when my computer would only say about 19.2. This is 8 tenths of a gallon, or about $2.60 in gas I am being cheated out of. I always pump gas in the tank until the pump clicks at least 2 times and you can tell the gas is as full as it needs to be...not overflowing at all, but plenty full.

The pumps at these stations consistently indicate I used 1/2 to 8 tenths a gallon more than the truck computer indicates, depending how much gas the truck takes at fill up.

At the next fill up, I went to another station that I had not checked out. When the tank was full, the pump indicated it took 19.0 gallons, and the computer indicated I used 19.4. I gained 4 tenths a gallon. The truck was level in both places and I filled the tank exactly the same each time. My next fill up will be at this same place to see if the pumps here are consistent with my previous fill up.

I suppose there is a percentage range that is acceptable to the gas pump inspectors, like maybe 5%. That could be extra 5% profit for the station if the pumps are shorting you 5%. I wouldn't think the truck computer would be off more than .1 or .2 gallons per tank full. That will be an acceptable shortage. Anything more than that will send me to another station.

Any other observations on this?
 

·
Registered
Joined
·
868 Posts
no but i am curious that you are filling your tank with 18 or 19 gal all the time !
i had an 04 F-150 triton with a 23 gal tank that would use typically 18-19 gal to top off but now this 13 has a 36 gal tank and i cringe every time i have to refill.
actually i have never filled it all the way in one stop because i start getting nervous when the price gets up around the $85-$100 and i usually just round it off and call it good enough.
 

·
Registered
Joined
·
327 Posts
I have never noticed this problem. But then again, I have never been looking for it. I will be filling my truck up today and I will check this out.
 

·
Registered
Joined
·
510 Posts
More stations than you realize have gas pumps that cheat you maybe 5 to 10% every time you fill up.
Exactly why I don't hand calculate fuel. Everybody says the truck is off, often calling the truck's MPG the "lie-o-meter". Well, why the heck do people not trust it but have full faith in the odometer/tripometer and fuel pump?
 

·
Registered
Joined
·
537 Posts
Unless you have a line drawn on the filler neck to where you can visually see that the tank is filled to that exact point each and every time you can not use the gallons pumped vs the trucks computer gallons used to judge whether the pump is shorting a percentage of a gallon per fill. There will also be factors such as needing to fill the tank at the same temp each time due to expansion and evaporation variations in temperature.

Bottom line, pump it, pay for it and head on down the road.
 

·
Registered
Joined
·
868 Posts
very very good point Jon, whether the truck is filled up in the morning or the evening can easily show 10% difference in volume and to get technical you would have to take a sample of the fuel and test temps to compare apples to apples
the temp effects gasoline volume pretty drastically when you are metering it
higher temps not only lower the density but also increase the evaporation rate alot more than you think.
 

·
Registered
Joined
·
9,640 Posts
Pumps are supposed to be certified and inspected by the Dept of Agriculture. At least here in Texas.



View attachment 3009


I reported this station because their 93 octane runs like crap.
 

·
Registered
Joined
·
510 Posts
They test the accuracy of 5 gallons. That's it.
 

·
Registered
Joined
·
138 Posts
When I bought the truck I averaged it to cost around $100 to fill it up. If its less then that I'm happy. I haven't had to spend more and every time it shuts off at full I haven't broke down the numbers to look but if its around $2 with a 26gal tank that's comes out to be a full tank of gas at reg prices ($3.70/gal) after 30 fill ups. Ill have to try and remember next few times I fill up to check.
 

·
Registered
Joined
·
59 Posts
Comparing your trip computer to corrected to a static temp fuel pump is like comparing a mixing cup to a graduated cylinder.

Sent from my SGH-I747M using Tapatalk 2
 

·
Registered
Joined
·
565 Posts
are you also hand calculating what your truck is getting for mpg cause i often find that my truck would be off form a hand calculation.
 

·
Registered
Joined
·
9,640 Posts
Texas has about 8 inspectors to cover the entire state.
Well, that explains the new stickers. The round ones used to be punched for the year of the last inspection.
 

·
Registered
Joined
·
21 Posts
Discussion Starter · #14 ·
no but i am curious that you are filling your tank with 18 or 19 gal all the time !
i had an 04 F-150 triton with a 23 gal tank that would use typically 18-19 gal to top off but now this 13 has a 36 gal tank and i cringe every time i have to refill.
actually i have never filled it all the way in one stop because i start getting nervous when the price gets up around the $85-$100 and i usually just round it off and call it good enough.
My truck holds 36 gallons, but I usually fill up at half a tank.
 

·
Registered
Joined
·
21 Posts
Discussion Starter · #16 ·
Comparing your trip computer to corrected to a static temp fuel pump is like comparing a mixing cup to a graduated cylinder.

Sent from my SGH-I747M using Tapatalk 2
It was not my trip computer. Was gallons used computer. One would think the computer would be very accurate in calculating gallons used, at least as much so as a station pump is in measuring gallons pumped. Temperatures were basically the same at each fill up. This was just an observation. I'm sure no pump or computer is 100% accurate. Would just like figures to be close. Maybe I'm out in left field on this.
 

·
Registered
Joined
·
565 Posts
It was not my trip computer. Was gallons used computer. One would think the computer would be very accurate in calculating gallons used, at least as much so as a station pump is in measuring gallons pumped. Temperatures were basically the same at each fill up. This was just an observation. I'm sure no pump or computer is 100% accurate. Would just like figures to be close. Maybe I'm out in left field on this.
I was just thinking that if it computes your mpg gallon wrong it could easly have the wrong gallons used.
 

·
Registered
Joined
·
7,394 Posts
I think you are over analyzing this. That's why hyper milers fill up very very slowly to make sure the tank and filler neck are completely full. It is basically impossible to fill a tank to a consistent level even going to two clicks. Even using the same pump. There are a few variables that affect this. One, temperature, as discussed. Two, load. A pump with more than one person using it will pump slower than someone using just one side of the island. The faster it pumps, the more back pressure which will turn the pump off faster. I have pumped gas several times at Costco with my s10 and if someone on the other side is pumping and their side cuts off, there will be a surge on my side and click off my side. Like the filler neck couldn't drain it into my tank fast enough.

I have also noticed that after the pump clicks off the first time and even the second time, I can still squeeze a lot of gas in. And sometimes it clicks off, then i try to squeeze more in, then clicks off again immediately.

Everyone pays attention to how much gas they pump. I really doubt that they are trying to short change anyone. Even if its only 5%.
 

·
Registered
Joined
·
510 Posts
100 cars fill up per day, 365 days in a year, on average the customers are shorted 1/2 gallon saving the store $1.50 per fill-up = $54,750 per year. The cynic in me says a store has a lot to gain by shorting you on fuel. Same reason why I pay for an oil change and it never seems to reach the top of the dipstick.
 
1 - 20 of 44 Posts
Top