Ford Focus Forum, Ford Focus ST Forum, Ford Focus RS Forum - View Single Post - Low MPG on new 2012 Titanium Hatch
View Single Post
Old 08-08-2012, 07:27 AM   #28
kam327's Avatar
Join Date: Feb 2012
Fan#: 94700
Location: Tampa, FL
What I Drive: '17 Mazda6 (traded in the Focus)

Posts: 2,710
Points 14,492, Level 78
Points: 14,492, Level: 78 Points: 14,492, Level: 78 Points: 14,492, Level: 78
Level Up 11% Completed
Level up: 11% Level up: 11% Level up: 11%
Forum Activity 15%
Activity: 15% Activity: 15% Activity: 15%
FF Reputation: 15 kam327 Great Standing Member
Buy-Sell-Trade Rating: (0)
Originally Posted by dyn085 View Post
Assuming this to be all users, this also supports what I'm saying. You aren't going to see a gain in 'engine break-in', whether that is 50 miles or 10,000 miles. My engine was broken in within the first 50 miles, given how I break my cars in. The only thing I would be concerned with, on these graphs, would be the very first 3 fill-ups or the 3 fill-ups following a master reset/battery disconnect. By the fourth tank, in my experience, I am at the mileage my car will get (not counting extreme changes in driving habits, another discussion).
We're talking about 2 different things then; I was always referring to the myth of long term mileage increase due to slow and steady break in. In your statement "it takes the PCM a while to 'learn' our styles and habits" I took "a while" to mean many months and thousands of miles. Like the 3rd poster on this thread who said "At about 1,500 miles I started seeing a steady, noticable increase in MPGs." I did the non-scientific analysis to look into long-term break in which many on this forum believe in, in other words a steady increase in mileage over the first 5,000 to 10,000 miles. Doesn't seem to happen with any consistency across the board.

And that's what I meant by Craigsfocus's graph supports my theory. If you were to apply a trendline to his graph it would show a pretty flat average of 30-31 mpg over his 3 months or so of data.

Originally Posted by dyn085 View Post
I would think that his graph supports mine. If his second fill-up was 25ish mpg, he is averaging (roughly, no Excel backing) at or over 30mpg. Assuming that his first tank was (as many are concerned with) lower mpg than his second, he would be seeing well over 7 mpg's gained simply by the ECU/PCM 'learning'.
I see what you're saying now, but everyone should just throw out and ignore their first tank's mileage. Most dealers "fill up" a tank for delivery but who knows how full they filled it, and if they drove it around some after filling it up. You'd have no way to know and it would throw off your first tank mpg calculation, and probably your 2nd tank's as well.
kam327 is offline  
    Reply With Quote