MPG from dash and Fuely are not the same - Fuelly Forums

Click here to see important news regarding the aCar App

Reply
 
Thread Tools Display Modes
 
Old 01-23-2019, 07:36 AM   #1
Registered Member
 
Join Date: Nov 2018
Posts: 1
Country: United States
MPG from dash and Fuely are not the same

Just curious how this all works. I have been fuelly for a few months now, and fuelly is always a bit lower than my estimated MPG that the car displays on the dash. I might see 32.1 MPG on the dash, but Fuelly will tell me 29.0 mpg. I could see it being slightly different (32.1 vs 31.8) but it has been a bit more than slightly. What is causing this and is there something I may be doing wrong? I always fill up the car completely each time.

Thanks
__________________

kd8tzc is offline   Reply With Quote
Old 01-23-2019, 08:12 AM   #2
LDB
Registered Member
 
Join Date: Jun 2013
Location: Houston suburb
Posts: 405
Country: United States
Location: Friendswood, (Houston suburb)
I call the dash reading the optimismeter because it's usually optimistic, although better on my current car than some. I've read numerous comments about the numbers being off compared to paper/pen numbers. I think it's just the nature of the beast. Fuelly seems to match paper/pen which makes sense since it's calculated not estimated.
__________________

__________________
2018 Accord Hybrid Champagne/Ivory

LDB is offline   Reply With Quote
Old 01-23-2019, 11:42 AM   #3
Registered Member
 
Join Date: Aug 2009
Posts: 2,712
Country: United Kingdom
Location: Mid Wales
The dash readouts are only guides, estimates, they are never accurate 100%. Mine read consistently 3.5 MPG higher than the actual fuelly calculations, not exactly, but on average. Yours actually appears pretty accurate, some are way way optimistic.
Draigflag is offline   Reply With Quote
Old 01-24-2019, 06:31 AM   #4
Registered Member
 
Join Date: Nov 2007
Posts: 1,585
Country: United States
Location: north east PA
The dash can be accurate. A calibrated Scangauge or other plug in meter is, and it is using the same data inputs as the dash display. It is just that manufacturers aren't required to have them be.
trollbait is offline   Reply With Quote
Old 01-24-2019, 07:47 AM   #5
Registered Member
 
Join Date: Jun 2017
Posts: 561
Country: United Kingdom
Location: Kirkcaldy
I use a ScanGauge E and my last set of mpg figures were:
Actual 52.4 mpg
ScanGauge 52.1 mpg
Onboard 53.1 mpg

However the previous top up was:
Actual 54.7 mpg
ScanGauge 52.9 mpg
Onboard 56.1 mpg

The reason the ScanGauge tends to be more accurate is down to the fact that, if necessary, you make a correction every top up. You correct the ScanGauge gallons added, to match the actual gallons added (I use half the difference as the correction factor).
For several top ups now I have not needed to make any correction as the difference has been no more than 0.1 gallons.
__________________
2006 Honda Jazz 1.2i-DSi S Vivid Blue Pearl
JockoT 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


Powered by vBadvanced CMPS v3.2.3


All times are GMT -8. The time now is 11:06 AM.


Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2019, vBulletin Solutions, Inc.