"Since Start" mpg accuracy?
Thread Starter
Senior Member
Joined: Sep 2008
Posts: 293
Likes: 3
From: Chicago
2002 E430 4MATIC
"Since Start" mpg accuracy?
I find that my "Since Start Up" mpg usually averages around 14mpg in mixed city driving. However, "Since Reset" will hover around 19 - 20 mpg after a few days. When I fill up and manually check mpg - it is right around what ever the "Since Reset" indication is.
Soooo.. how do I get 20mpg when the "Since Start Up" never reads anywhere that high when I shut down? This only happens when I'm running several days on a tank. On a long trip "since reset" always = "since start up" and both are accurate.
As an observation if I'm driving at a steady state 70 mph and re-set the mpg computer it will quickly show something like 15mpg, even if I'm coasting, where I would expect something like 99 mpg. It it will eventually tick up .1mpg at a time to a more accurate 25mpg but it might take 50miles of driving.
No big deal... just wondering why the short cycle mpg calculation is so understated.
Soooo.. how do I get 20mpg when the "Since Start Up" never reads anywhere that high when I shut down? This only happens when I'm running several days on a tank. On a long trip "since reset" always = "since start up" and both are accurate.
As an observation if I'm driving at a steady state 70 mph and re-set the mpg computer it will quickly show something like 15mpg, even if I'm coasting, where I would expect something like 99 mpg. It it will eventually tick up .1mpg at a time to a more accurate 25mpg but it might take 50miles of driving.
No big deal... just wondering why the short cycle mpg calculation is so understated.
