Toyota Sienna Forum - siennachat.com banner

1 - 6 of 6 Posts

·
Registered
Joined
·
3 Posts
Discussion Starter #1
HI,

I'm not sure if this has been ask before. If so, i'm sorry for asking again. I'm new to the site. Anyway, on to the question.

I have a 2015 Sienna LE with about 50,000 miles. I've notice that when filling the gas tank to full, my Gas Mileage indicator would have different readings? I'm not talking about a few miles. More like 10 to 40 miles different.

I've notice that while filing up at a Sam's Club gas station to full, my indicator would reflect that I have "282" miles before empty. But if I were to fill up at a different gas station, it would be somehwere in the "340" miles.

It's not always the same gas station that is lower. Anyone know why the difference is so large??
 

·
Registered
Joined
·
204 Posts
The calculation is based on your recent average MPG calculation. If you drove on the highways a bit more during two fill ups, it may read higher, if you drove mostly in the city, it may indicate lower. It will adjust itself over time as the tank empties.
 
  • Like
Reactions: circus

·
Registered
Joined
·
82 Posts
There are 2 likely elements in play:
1. The most recent MPG, which will vary by drive cycle and driver. Recent 'extensive idle' or 'crawl-and-crawl some more' driving will give relatively low miles to empty than a recent moderate-speed highway trip.
2. The amount of fuel you were able to put in, given the vent situation. This will get impacted by ambient temps and fuel nozzle. Some cut off sooner than others, and sometimes the tank vent does not allow fumes to escape / get vented fast enough, so the nozzle will shut off. because of 'burps' up the filler. This could be an actual or developing fault in the fuel tank venting system. I found the 'vapor recovery' nozzles particularly fussy, resulting in 1-2 gallons less 'fitting' in the tank.
There is a third possibility, the gas station pad. Most are relatively flat, but I found a few with a slope, and that can make a difference in filling. The Sienna tank has a nominal capacity of 20 gallons - of which ~ 18 or so is usable. The tank shape, driven by its location, is such that a few degrees tilt will make a difference in how much it will accept.
 

·
Registered
Joined
·
3 Posts
Discussion Starter #5
The calculation is based on your recent average MPG calculation. If you drove on the highways a bit more during two fill ups, it may read higher, if you drove mostly in the city, it may indicate lower. It will adjust itself over time as the tank empties.

Thank you for the info.
 

·
Registered
Joined
·
3 Posts
Discussion Starter #6
There are 2 likely elements in play:
1. The most recent MPG, which will vary by drive cycle and driver. Recent 'extensive idle' or 'crawl-and-crawl some more' driving will give relatively low miles to empty than a recent moderate-speed highway trip.
2. The amount of fuel you were able to put in, given the vent situation. This will get impacted by ambient temps and fuel nozzle. Some cut off sooner than others, and sometimes the tank vent does not allow fumes to escape / get vented fast enough, so the nozzle will shut off. because of 'burps' up the filler. This could be an actual or developing fault in the fuel tank venting system. I found the 'vapor recovery' nozzles particularly fussy, resulting in 1-2 gallons less 'fitting' in the tank.
There is a third possibility, the gas station pad. Most are relatively flat, but I found a few with a slope, and that can make a difference in filling. The Sienna tank has a nominal capacity of 20 gallons - of which ~ 18 or so is usable. The tank shape, driven by its location, is such that a few degrees tilt will make a difference in how much it will accept.

Thanks. Wow. Didn't know that. But do now.
 
1 - 6 of 6 Posts
Top