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true mpg?

when I got my 2013 brand new had to drive about 50 miles home. Noticed in the fuel economy mode it said averageing 11mpg. When I refilled the tank I'm getting 15mpg around town,23 on highway. I called the service department and the tech. said it takes up to 1000 miles before the pcm learns all the calibrations. What does yours say? Is it accurate or does it take time to learn? that makes it off by almost 25%. now 550 miles and still not right.
 

zzyzx

Steve
299
0
Not sure exactly what you're saying.

Are you saying that when you refill, you measure how many gallons it takes to fill up, and do the math - and that that doesn't agree with what the gauges say?

If so, are you resetting the gauges after each refill?
 

BLAZN BOSS

I'm not sure about 2013's but I'm sure they are the same as 12's...........the MPG begins measuring from day 1 not from fill up to fill up.............disconnect your battery and youll see in about 5 miles what your true MPG is.
I found this out with my daughters 2010 mustang...........disconnect the battery to do some interrior work and always wondered why her V6 had not too terrific MPG.......well when I re-started it the MPG was 0...........then after a few miles it was up to 29.
 
What I'm trying to say is I fill the tank,gauge says I average 11.6 mpg ,reset gauge then I refill 5 days later and do the math and average 15 mpg. gauge says 11.6 my math says 15. Tech tells me it takes up to 10 tank-fuls for the gauge to be accurate,does this sound right?
 
It takes a while, and a couple trips to the right side of the tach can throw it off. Same with any car, afaik none of them work by measuring fuel use and comparing it to distance traveled directly but instead calculate it based on some sort of averaging. I have found that they are not particularly accurate in any of my cars, though it is usually within a couple mpg. Try coasting downhill and resetting it, in most cars it will show 99 or error. Also idling a lot will mess with it.
 

Boostd4

Relapsed Turbo Addict
161
0
F.D. Sako said:
I've been averaging 17-18mpg with mixed driving and your occasional a-hole style accelerations here and there lol

LOL, well said sir.

I was going to write the same thing. I'm using FuelLog on my phone to track milage, oil changes, etc. The onboard fuel computer is probably decent for realtime milage...but the averages are all way off.
 
Boostd4 said:
LOL, well said sir.

I was going to write the same thing. I'm using FuelLog on my phone to track milage, oil changes, etc. The onboard fuel computer is probably decent for realtime milage...but the averages are all way off.

might have to check out that app. maybe it'll help me be more conservative on that gas pedal lol
 
I've always check my mileage when I fill up and when my car was new [May 2011] I noticed my actual calculated mileage was always 1-2 mpg better than what the cars driver information was telling me. As time went on I noticed that the cars calculation is now very accurate. Not sure if the car learns to more accurately calculate fuel consumption or if the sensor is drifting and just happens to be in an accurate range right now. Only time will tell.
 

ufnavy06

Some say he has a tattoo of his face on his face.
I keep a running log inside the car so I can analyze the trends in the car. Something my dad taught me. It's an old school pen and small notepad but it's always right there. I unfortunately can't tell you what the numbers are now (I'm in Australia right now actually), but I'm pretty confident the computer was always pretty accurate, somewhere around 18 mpg.
 
I drive about 12 miles round trip on backroads to work everyday. I drive it like I stole it. I reset the guage every full up. Gauge usually reads about 8 mpg. Interstate driving is a lot different. Usually get onto the very low 20s . I always wondered if the track key and or the open side pipes make any difference on mpg. Of course I didn't buy this car for the gas mileage. Just curious.
 

Justin

Save the dawn for your dishes!!!
Steve said:
Ummm oh what we're we talking about? I'm still looking at your profile pic.
I love that pic too lol. Leaves me wondering was it taken in person or found online and made into a avatar and if it was taken in person why are there not more pictures? lol
 

Boostd4

Relapsed Turbo Addict
161
0
F.D. Sako said:
Boostd4 said:
LOL, well said sir.

I was going to write the same thing. I'm using FuelLog on my phone to track milage, oil changes, etc. The onboard fuel computer is probably decent for realtime milage...but the averages are all way off.

might have to check out that app. maybe it'll help me be more conservative on that gas pedal lol

Hah, well I don't really use it to keep my foot out of the go pedal...but it's great for tracking maintenance items since I have two cars. Although, the app does provide all kinds of geeky metrics around costs and trends. But just like anything else you have to use it religiously or else the data will be meaningless.
 

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