Is this unique?

Miss_Athanatos · May 22, 2016

To my recollection, my average calculated MPG is right around 50 over the life of the vehicle. However, as the summer fuel mixture has come out, I'm back to seeing 60 MPG and better on the computer readout.

Today I saw 69.6 MPG over a 35 mile drive, mostly highway. Is this what other people usually see on their computer readouts?

Thanks in advance.

-- Nicole

Miss_Athanatos · May 22, 2016

jettawreck · May 23, 2016

Do you believe it??
Do an actual log of miles/gallons used over several tanks and see how much error the dash read out gives you. Then you will know how accurate it is. Or isn't.

applejacks · May 23, 2016

As always, keep paper records. That said, I have found my on-board computer to be fairly accurate.

BTW, that display....pretty sweet! How did you get that?

Miss_Athanatos · May 24, 2016

jettawreck said:
Do you believe it??
Do an actual log of miles/gallons used over several tanks and see how much error the dash read out gives you. Then you will know how accurate it is. Or isn't.

You're right, the accuracy of the display is always questionable, as I've
seen over the life of the vehicle thus far. I've compared my calculations
to the extended driving MPG average on the car and seen some deviation,
but what I'm interested to know is: are other people seeing this high of
number on their computer readouts?

Miss_Athanatos · May 24, 2016

applejacks said:
As always, keep paper records. That said, I have found my on-board computer to be fairly accurate.

BTW, that display....pretty sweet! How did you get that?

Thanks. The display was stock in 2015 vehicles.

Dcwhybrew · May 24, 2016

Wow...that is pretty high. The highest I have seen on my per trip display is 49 mpg. My actual calculated mpg average 39-40. Sometimes I get 41-42 calculated. My trip computer average mpg between fill-ups is usually 1.5-3 mpg higher than the calculated mpg.

Miss_Athanatos · May 26, 2016

Dcwhybrew said:
Wow...that is pretty high. The highest I have seen on my per trip display is 49 mpg. My actual calculated mpg average 39-40. Sometimes I get 41-42 calculated. My trip computer average mpg between fill-ups is usually 1.5-3 mpg higher than the calculated mpg.

I've only had the car for about 10 months now. I saw my MPG average
drop off drastically in the winter to around a 40 MPG calculated, but
now that summer has come back the calculated average is around
50 MPG. I've seen anywhere from .3 to 4 MPG higher displayed on the
computer readout for the "since refuel" MPG average. It seems as the
computer displays higher MPGs, there is more discrepancy between the
computer and the calculation of miles per gallons of fuel.

bobgolf2004 · May 27, 2016

Real examples:

Mpg's per fill up (2015 Passat 6M).... 93-95% of what computer says. Computer set at "100%" (i.e., computer says 58 mpg for the tank...calculated MPG 54-55 mpg actual)
Mpg's per fill up (2006.5 Jetta DSG)....88-90% of what computer says,with computer set at "115%". I rest computer to "115%." Factory setting was set at "100%" and the actual mpgs would be 80-83% of what the computer said.

5/25/2016 (Passat) - 29 mile loop,all highway...70 mpg per computer.
coming back...12 miles at 58 mpg per computer (I always get more mpg in the one direction, and less in the other)

Yes, when the conditions are right, you can see some pretty high mpgs. But the "right" conditions are not the "typical" conditions. For a tank in the Passat, I usually see an average of 52-58 mpg per computer.

Miss_Athanatos · May 27, 2016

bobgolf2004 said:
Real examples:

Mpg's per fill up (2015 Passat 6M).... 93-95% of what computer says. Computer set at "100%" (i.e., computer says 58 mpg for the tank...calculated MPG 54-55 mpg actual)
Mpg's per fill up (2006.5 Jetta DSG)....88-90% of what computer says,with computer set at "115%". I rest computer to "115%." Factory setting was set at "100%" and the actual mpgs would be 80-83% of what the computer said.

5/25/2016 (Passat) - 29 mile loop,all highway...70 mpg per computer.
coming back...12 miles at 58 mpg per computer (I always get more mpg in the one direction, and less in the other)

Yes, when the conditions are right, you can see some pretty high mpgs. But the "right" conditions are not the "typical" conditions. For a tank in the Passat, I usually see an average of 52-58 mpg per computer.

Thank you for your detailed write-up.

ezshift5 · May 28, 2016

Miss_Athanatos said:
You're right, the accuracy of the display is always questionable...............

That (above) is a study in tact and politeness..........

For nearly 38,000 mies, the variation of my MFI from the calc'd (miles driven by gallons pumped) MPG is all over the board

For example MFI today showed 44.5 - calculations showed 44.56. In over 3 years it has NEVER been that close (MFI usually 5 - 10% optimistic).

ez

koop · Jun 6, 2016

Miss_Athanatos said:
To my recollection, my average calculated MPG is right around 50 over the life of the vehicle. However, as the summer fuel mixture has come out, I'm back to seeing 60 MPG and better on the computer readout.

Today I saw 69.6 MPG over a 35 mile drive, mostly highway. Is this what other people usually see on their computer readouts?

Thanks in advance.

-- Nicole

That is very high numbers, VW must have trick the SW reading .. wink wink

I have a '10 Jetta TDI and have monitored the MPG since day 1, with all different driving, long/short trips, freeway , hot and cold days... the most I see was 53 on a cold day at 55 - 60 mph. Of course you can do a reset while on freeway and down hill, you may hit that kind of MPG

Miss_Athanatos · Jun 18, 2016

koop said:
That is very high numbers, VW must have trick the SW reading .. wink wink

I have a '10 Jetta TDI and have monitored the MPG since day 1, with all different driving, long/short trips, freeway , hot and cold days... the most I see was 53 on a cold day at 55 - 60 mph. Of course you can do a reset while on freeway and down hill, you may hit that kind of MPG

It could very well be some trick from the factory, eh?

I've found with a lot of my driving that the instantaneous MPG readout blinks
out, as 300 MPG is the max it will report. I used to drive a lot with neutral
coasting, but I've stopped that since I saw that instantaneous MPG reported
by the readout is much lower out of gear than in gear.

I haven't had occasion to refill my tank yet since this thread was opened,
so I don't have a revised calculated average yet.

Save

IndigoBlueWagon · Jun 19, 2016

This is why I don't like MFD FE readouts. They're misleading. It is typical to see a drop in FE in the winter, especially in the newer cars where they use fuel to help heat up the emissions system on a cold start. Winter fuel also has fewer BTUs than summer fuel. 3-4 MPG is not unusual.

Based on what other reports, high 40s in Summer would not be unusual. But base this on full tank fills hand calculated. If you compare these to the cluster readouts you'll have better data on the amount of error in the MFD.

Lincoln · Jun 21, 2016

Best I've ever seen on a drive of any length was 64mpg on the MFI. (I've seen higher on short trips that were mostly down hill, so those don't count for obvious reasons.) That was definitely atypical though, since the next best that I've seen (a few different times on 40 mile commute) was 60mpg. More normally, under close to ideal conditions, I would get 55-58 on the MFI for a long commute.

There are some who report getting averages above 60mpg, but those usually have ideal conditions and practice some form(s) of hypermiling techniques. Most get much lower #s on the display.

So in short, no, that is not what other people usually see on their readouts. A handful do hit numbers like that on rare occasions though.

jjk58 · Jun 22, 2016

my 14jsw mfi shows at least 5% high but it varies. dealer claims they can't adjust and it's known. I heard I can adjust if I had vagcom but I would be reluctant under warranty. I track the difference in my fuelly notes.

tactdi · Jun 23, 2016

Adjusting the MPG within the MFI by using VCDS does make it more accurate, sometimes.

I adjusted my MFI several times using VCDS.
The most accurate it shows comparing to calculated full tanks is for constant travel. Like all city or all highway.
I track what the MFI says compared to my calculated value, and sometimes it is off by 1/2 mile, sometimes it
is off by several miles. I do get a smile when the MFI is very close to my calculated value.

Is this unique?

Miss_Athanatos

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