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John___Angela's avatar
May 19, 2014

Scangauge II giving unrealistic mileage numbers on V10

Hello all. I bought a scan gauge over the winter for the purpose of monitoring transmission and engine temp on our little 22 foot B/C motorhome. I mounted the spare tire up front and was concerned with airflow. All that worked out fine BUT I started playing with the various mileage features etc. on the last few trips I have been getting 13.8 to 14.8 for MPG in US gallons. This I find hard to believe and am questioning the setup. All parameters double checked, US mpg, V10, displacement etc. everything looks right. I have not actually done it old school yet by checking fuel consumed on a given distance and won't have a chance till we get back from Europe. Any ideas? We tend to never go over 90 KMH or about 55 mph. Still seems way high. Would expect 10 to 11 max.

Here's the coach. What am I doing wrong.

16 Replies

  • K. Will do that when we get back. Don't really care much about the mileage but I guess it would be nice to know. Like I mentioned, the peace of mind of knowing the transmission temp is worth it.
  • timmac wrote:
    You have to read the manual, it says for correct fuel millage you need to fill tank and with scan gauge on you enter the miles driven at next fuel up, it needs to be done 2 or 3 times to properly get correct fuel mileage reading, this is how you set up the fuel mileage gauge.


    X2 To get accurate readings you need to be consistent as to how full you get the tank. The SC will predict how many gallons it will take and then adjust /correct based upon what you actually fuel and enter into the SC. Mine is usually within a couple of tenths of a gallon if I fill up properly.

    Our 2012 24' C V-10 gets between 9-10+ depending on speed, weather and road conditions and I love having trans fluid temps as well.

    :C
  • Hi,

    Those calculations concerning the tank size do not affect the instantaneous fuel consumption (gph).
  • You have to read the manual, it says for correct fuel millage you need to fill tank and with scan gauge on you enter the miles driven at next fuel up, it needs to be done 2 or 3 times to properly get correct fuel mileage reading, this is how you set up the fuel mileage gauge.
  • Suggestion is you go back and read up on the scangauge. It reports an approximation of gas mileage. As to get real MPG you need a turbine flow meter inline with the fuel delivery.
    In the manual they discuss how to adjust the MPG under the advance features.
  • Hi,

    Are you sure you did not set it for Imperial Gallons?

    Your RV does have a better "flying brick" profile than mine, but if I take my long term US gallon numbers and move them to imperial I do get close to your numbers.

    I found a "sweet spot" at 78 kph, so I'm driving quite a bit slower than you--but I weigh more and am longer, too.

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