Toyota FJ Cruiser Forum banner
1 - 7 of 7 Posts

·
Registered
Joined
·
199 Posts
Discussion Starter · #1 ·
With the price of gas so high, I started watching the scan guage instantaneous mileage more often and driving accordingly. Seems to have brought up my average mpg from 14 to 17, though some of this is due to the engine getting broken in.

I have a 6MT and its 90% city driving.

But another thing I noticed was peculiar. When I first got the scanguage 6,000 miles ago, I put in the setting for gas tank size, and then adjusted the extra gallons as read on the pump at every fillup.

However, I got tired of adjusting it at every fillup since it was as much as 0.8 gallons over what scanguage told me I had used. I figured temperature, pump itself and the how much I actually pumped in made a difference. I mostly fill up at the Big Oil company franchises like Mobil and Shell. Most of the time the adjustment is +0.4 to +0.8 gallons, and I don't adjust it. Last time I filled up at a Meyer gas station (Grocery chain) and the guage actually read what the pump said I put in!

Even though all pumps are inspected and have stickers on them for accuracy etc, could it be that Meyer is giving me the honest amount of gas and the others are skimming off upto 0.8 gallons. I trust the scanguage more than the state pump inspectors.

Anyone noticed anything similar?
 

·
Premium Member
Joined
·
7,729 Posts
the scanguage is more of an approximation. you must put in the exact amount every time for it to be close, but say one day you floor it to get around some jerkhole in a prius, well your guage will be off next fill up by a hare because it is just an appromate averege that learns from your input trends. Usually mine is spot on but some days I feel myself pushing the truck more than others and I have to adjust it at the pump. Also yeah I averege 13 to 16 mpg weekly. I see it over 17 sometimes but with stop and go it drops quickly.
Actually trusting the pump and doing your own math would be more accurate than the scan gauge, but toys are easier and more fun to play with than notebooks and numbers.
 

·
Registered
Joined
·
94 Posts
The shutoff point can vary from pump to pump. You should use the same pump 2 or 3 times to get it calibrated right. Also, if the oil companies don't compensate for hot/cold gas, that can change you readings too, so fill it up at the same pump, preferably in the morning before the sun has had time to warm up the underground tanks. Hot gas expands and unless you live in the north or law requires it, oil companies don't compensate for it. One gallon of gas is defined by volume at a certain temperature, around 70 I think.
 

·
Premium Member
Joined
·
6,534 Posts
Dispensers are calibrated to be very accurate and are checked by the local weights and measures folks on a regular basis. There's no way that a dispenser would be off 0.8 gallons on a 15 gallon fill. They would we hauling folks off in handcuffs at that point. Each pump has a sticker on it and it says when it was last checked.

DEWFPO
 

·
Registered
Joined
·
139 Posts
I have to adjust mine every time I fill up. I usually let it fill until it clicks off on its own and I don't put anymore gas in it. I have all kinds of supposedly gas saving items, ie, cold air intake, high dollar oil and tranny/rear end oil, shift at 3k rpm and I still cant get more than 14 usually 12 around town. Sucks. But luckily for me I have a K75 RS motorcycle that gets 50 mpg and I use it alot.
 

·
Texican
Joined
·
8,570 Posts
Dispensers are calibrated to be very accurate and are checked by the local weights and measures folks on a regular basis. There's no way that a dispenser would be off 0.8 gallons on a 15 gallon fill. They would we hauling folks off in handcuffs at that point. Each pump has a sticker on it and it says when it was last checked.

DEWFPO
Woodlands company faces lawsuit over gas pump output | Houston & Texas News | Chron.com - Houston Chronicle

They don't just slap your hand...
A recent investigation by the Texas Department of Agriculture revealed that 985 Sunmart pumps of about 1,700 tested were dispensing less fuel than required. Many of the violations took place in the Houston area.

Each violation carries a civil penalty up to $20,000. If only one customer pumped gas from the 985 pumps, the company could face a daily fine of nearly $20 million.
 
1 - 7 of 7 Posts
Top