Just a quick question about how fuelly calculates my mpg - Fuelly Forums

Click here to see important news regarding the aCar App

Go Back   Fuelly Forums > Fuel Talk > General Fuel Topics
Search Today's Posts Mark Forums Read Click Here to Login
Reply
 
Thread Tools Display Modes
 
Old 01-02-2011, 12:21 AM   #1
Junior Member
 
Join Date: Jan 2011
Posts: 5
Country: United Kingdom
Location: Pontypridd
Just a quick question about how fuelly calculates my mpg

Just a quick question about how fuelly calculates my mpg

Just a quick question about how fuelly calculates my mpg, with my current car i only ever fill it up with 20l at a time and then refill once the fuel light starts flashing at me and always have now would fuelly be calculated my mpg correctly this way if i dont enter it as a partial refil?

dont really want to chuck a full tank in to work it out as it seems too costly
__________________

astrasxicdti is offline   Reply With Quote
Old 01-02-2011, 07:16 AM   #2
pb
Senior Member
 
Join Date: Jul 2008
Posts: 1,588
Country: United States
Location: Corvallis, OR
Based on how you're adding fuel I don't think Fuelly is going to work for you. Here's more info in the FAQ: Why do I have to fill the tank all the way up every time I buy fuel? and a recent discussion we had about filling up: Why fill my tank?
__________________

pb is offline   Reply With Quote
Old 01-02-2011, 04:24 PM   #3
Junior Member
 
Join Date: Jan 2011
Posts: 5
Country: United Kingdom
Location: Pontypridd
ok thanks funny how shedding weight aids mpg but you all drive around with a full tank
astrasxicdti is offline   Reply With Quote
Old 01-04-2011, 09:43 PM   #4
Senior Member
 
Join Date: Oct 2009
Posts: 216
Country: United States
Location: EUP Michigan
If weight was such a direct issue to MPG, then people who are large vs people that are small would have way different MPG ratings.

Honestly I doubt the weight of the fuel has that much of an impact. Up here, especially in winter, you don't want to be running around on a half tank - near empty tank. If you go in the ditch on a late night, you may be there for a while with the engine running to keep warm. Not to mention, if you kept it full, but refilled it at say half tank, it would be the same system you are on now, only this way you would have a buffer for emergencies.

Just my 2 cents. I just think all this filling partway and running it dry is plain, well, stupid to be honest. Don't hate me, but that's how I see it. But to each his/her own I guess.
DTMAce is offline   Reply With Quote
Old 01-06-2011, 09:25 AM   #5
Registered Member
 
Join Date: Feb 2009
Posts: 30
Country: United States
Location: Laughlin, Nevada
From what I understand reading various automotive magazines and forums, running the fuel that low also doesn't do the fuel injectors any favors. Contaminants that settle to the bottom of the tank are much more likely to get pulled into the system and clog the injectors. Not worth the risk for the little you save on fuel by filling that way. Repairing the fuel injection system on a car will cost more than you saved on fuel.

Better idea might be to put your limited amount of fuel in when the tank hits 1/4 instead of running it as low as you do. You'd still not be carrying the weight of a full tank but it would be better for the car.
__________________
2008 Toyota Prius Touring purchased 04/2016 at 101k miles, currently at 186k miles
2009 Acura MDX purchased 12/2019 at 159k miles, currently at 194k miles
srellim234 is offline   Reply With Quote
Old 01-06-2011, 07:29 PM   #6
Member
 
Join Date: Jun 2009
Posts: 69
Country: United Kingdom
Location: Windsor
Think about it logically, the fuel must be drawn off from the bottom of the tank, otehrwise you would run out with gallons left in it !
udtrev is offline   Reply With Quote
Old 01-07-2011, 03:18 AM   #7
Senior Member
 
Join Date: Oct 2009
Posts: 216
Country: United States
Location: EUP Michigan
And here we go with the dirt at the bottom of the tank myth again. Nearly all late model cars pull the gas from the bottom of the tank anyway guys, that's how the pump works. And, unless you are fueling during a dust storm, your dirt in the tank is going to be minimal. I recently changed the 212 thousand mile gas tank on my 17yr old Z and guess what? It was practically spotless and dirt free on the inside. I changed it due to bad outer rust, but it had not contaminated the inside. SO, that excuse is not really valid, especially for newer vehicles.

Moral to the story? Just fill it up, and soldier on. Its a lot less painful... LOL
DTMAce is offline   Reply With Quote
Old 01-07-2011, 03:23 AM   #8
Senior Member
 
Join Date: Oct 2009
Posts: 216
Country: United States
Location: EUP Michigan
I will admit there are some arguments about keeping some fuel in the tank to keep the pump covered and cool. There are some notes about people that ran their tank mostly empty all the time shortening the life of their fuel pump... So there is that to think about too.

Anyways.
DTMAce is offline   Reply With Quote
Old 01-07-2011, 06:26 AM   #9
Registered Member
 
Join Date: Feb 2009
Posts: 30
Country: United States
Location: Laughlin, Nevada
While all fuel is pulled from the bottom of the tank, overall agitation of the sediment is more likely to occur and be picked up by the system when the fuel level is so low it increases said agitation. Same way as when you pull the plug on a bathtub. Dirt laying at the perimeter of the tub begin moving and increased levels of dirt go down the drain at the end of the draining.

You are absolutely right about the fuel pump cooling and failure.

From http://www.2carpros.com/articles/how-fuel-pump-works

"Some causes of fuel pump failure can include rust or dirt because they can get past the inlet filter sock, which is designed to filter these sediments. When this occurs the fuel pump will break down because of contaminants that have infiltrated the pump and cause it to jam. This will result in having the motor overheat and burn out. Sometimes a fuel pump will not work properly if it is not given the proper amount of fuel needed to run adequately. Your vehicle’s fuel pump relies on fuel running through it to cool and lubricate it. Starving your fuel pump for fuel can cause your vehicle's fuel pump to fail prematurely. Mechanical fuel pumps usually rupture the diaphragm that is used as the pump, and will leak a small amount of fuel externally (from the weep hole) or just not have pressure."
__________________
2008 Toyota Prius Touring purchased 04/2016 at 101k miles, currently at 186k miles
2009 Acura MDX purchased 12/2019 at 159k miles, currently at 194k miles
srellim234 is offline   Reply With Quote
Old 01-09-2011, 10:38 AM   #10
Senior Member
 
Join Date: Oct 2009
Posts: 216
Country: United States
Location: EUP Michigan
Still, said dirt is not going to be happening with a car less than 10 years old, let alone those that are older. Those with cars less than 5 years should NOT be having dirt in the fuel, unless they are leaving their gas caps off all the time and the lid open... I will admit there are some of you out there...

Yeah you, the lady with the big SUV. Stop talking on your cell phone while filling up and make sure you close your tank up properly. (seriously, I watched some woman do exactly that one day. And she got mad at me when I said something about it, imagine that)

Anyway, for those of us that fill up properly, there shouldn't be any dirt issues.

But I still stand by my original statement. Just fill up your tank (if you can afford to) or keep it half-full, rather than empty to half. Its better for you and your car.

Peace and good MPGs!
__________________

DTMAce is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


» Fuelly iOS Apps
Powered by vBadvanced CMPS v3.2.3


All times are GMT -8. The time now is 02:32 AM.


Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2024, vBulletin Solutions, Inc.