MPG guage updated?

hotbrass · 11-02-2009, 12:58 PM

Is there a TSB on MPG/ODO deviation. I assume they would not jack with MPH.

ScanGauge is close enough for me. I also do the calculation every time I fill up. None of the three match or even come close all the time. Mostly the SG and calculation are the closest.

a64pilot · 11-02-2009, 06:10 PM

It's not "broke", they aren't going to "fix" it, it works exactly as intended, and I bet 95% of owners aren't smart enough to know any better.

ALS · 11-02-2009, 06:26 PM

Quote:

Originally Posted by a64pilot

It's not "broke", they aren't going to "fix" it, it works exactly as intended, and I bet 95% of owners aren't smart enough to know any better.

You hit the nail on the head with that statement.

hotbrass · 11-03-2009, 09:49 AM

Of course its not broke. Its just wrong. If the gas gauge was calibrated incorrectly, it would not be broken, just wrong. I bet they would fix that, well, maybe not.

In software, it is called an "undocumented feature."

raysprius · 11-17-2009, 01:16 PM

July '09 manufacture date and MPG gauge consistently 1 - 3 mpg high relative to fill-up calculations. Comments on Fuelly.com indicate this is common. Calculations and MPG gauge should use the same distance data so that does not explain the difference. Measuring accurate fuel flow is an inexact science which requires fuel specific gravity, temperature, flow correction adjustments, etc., etc., etc. I imagine the flow meters used on cars are cheap and inherently inacurate (my BMW's MPG gauge is also 1 - 3 mpg high). While the gauges are not accurate they are useful as relative indicators of fuel usage which is probably all they were intended for.

codybigdog123 · 11-17-2009, 04:50 PM

I now have over 2,700 miles on my GenIII. I fill up once a week, every week since taking delivery in August. Every week the difference between the measured and computer generated MPG is 2-3 MPG, with the measured value always being lower, but always higher than the combined EPA number of 50 MPG.

I now have a high degree of confidence that when the diplay says I'm getting 54 MPG, I'm probably getting closer to 51 or 52 MPG. As stated above, there are errors associated with both the measured and displayed MPG figures. So what? Is this really a big deal?

11-02-2009, 12:58 PM	#11
hotbrass Senior Member Join Date: Sep 2009 Location: Cowtown Posts: 224 My Car: 2010 Prius Model: IV Package: Base Thanks: 24 Thanked 16 Times in 13 Posts Friends: 0	Re: MPG guage updated? Is there a TSB on MPG/ODO deviation. I assume they would not jack with MPH. ScanGauge is close enough for me. I also do the calculation every time I fill up. None of the three match or even come close all the time. Mostly the SG and calculation are the closest.

11-02-2009, 06:10 PM	#12
a64pilot Senior Member Join Date: Aug 2008 Location: Albany Ga. Posts: 732 My Car: 2010 Prius Model: III Package: N/A Thanks: 19 Thanked 45 Times in 40 Posts Friends: 0	Re: MPG guage updated? It's not "broke", they aren't going to "fix" it, it works exactly as intended, and I bet 95% of owners aren't smart enough to know any better.

11-03-2009, 09:49 AM	#14
hotbrass Senior Member Join Date: Sep 2009 Location: Cowtown Posts: 224 My Car: 2010 Prius Model: IV Package: Base Thanks: 24 Thanked 16 Times in 13 Posts Friends: 0	Re: MPG guage updated? Of course its not broke. Its just wrong. If the gas gauge was calibrated incorrectly, it would not be broken, just wrong. I bet they would fix that, well, maybe not. In software, it is called an "undocumented feature."

11-17-2009, 01:16 PM	#15
raysprius Junior Member Join Date: Sep 2009 Location: St Petersburg, FL Posts: 1 My Car: 2010 Prius Model: II Package: No Package Thanks: 0 Thanked 0 Times in 0 Posts Friends: 0	Re: MPG guage updated? July '09 manufacture date and MPG gauge consistently 1 - 3 mpg high relative to fill-up calculations. Comments on Fuelly.com indicate this is common. Calculations and MPG gauge should use the same distance data so that does not explain the difference. Measuring accurate fuel flow is an inexact science which requires fuel specific gravity, temperature, flow correction adjustments, etc., etc., etc. I imagine the flow meters used on cars are cheap and inherently inacurate (my BMW's MPG gauge is also 1 - 3 mpg high). While the gauges are not accurate they are useful as relative indicators of fuel usage which is probably all they were intended for.

11-17-2009, 04:50 PM	#16
codybigdog123 Senior Member Join Date: Sep 2009 Location: Chicago, Il Posts: 101 My Car: 2010 Prius Model: IV Package: Solar Roof Thanks: 0 Thanked 11 Times in 11 Posts Friends: 0	Re: MPG guage updated? I now have over 2,700 miles on my GenIII. I fill up once a week, every week since taking delivery in August. Every week the difference between the measured and computer generated MPG is 2-3 MPG, with the measured value always being lower, but always higher than the combined EPA number of 50 MPG. I now have a high degree of confidence that when the diplay says I'm getting 54 MPG, I'm probably getting closer to 51 or 52 MPG. As stated above, there are errors associated with both the measured and displayed MPG figures. So what? Is this really a big deal?

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