mpg calculation fix? - The Unofficial BMW M5 Messageboard (m5board.com)

SCM5 · 9th January 2009, 04:38

I did a search and saw a couple posts regarding high mpg figures given by the on-board computer but didn't find a fix for it.

I was originally searching the observed fwy mileage of the M5 (i've had it for only ~300 miles) and so far I'm getting an observed mpg of 31mpg fwy and 21 mixed which I thought was absurd.

Turns out with searching, people have posted around the same results and it seems to be due to the computer calculating the mpg using UK gallons or something instead of US gallons?... i didn't come across any fix for this during my search.

Any help would be much appreciated... thanks.

chowdah · 9th January 2009, 05:35

The search term you probably want is "euro mode" and the solution has been offered by members such as "Hawkwind". If you confirm euro mode on your NAV (yards not feet, accept screen absent), then the imperial gallons can be removed by a dealer, or you can disconnect your battery.

My setup is no accept screen + yards + US gallons. I'm happy with it. FYI, Aux Ventilation and Route Magnet are additional things that are affected in the Euro vs US alternatives.

jclyman · 9th January 2009, 06:02

I am not familiar with Hawkwind's fix.

First, make sure you are using the correct units (metic or USA).

Then go to the "secret console" menu. One of the entries equals 1000 (normal, and optimistic numbers result). (I think it is number 17, but not 100% sure.) If the number is less than 1000, more optimistic numbers will result, if higher less optimistic numbers will result, in the computer display. 1055 will be fairly close.)

Change the 1000 to 1055 for starters (push the left hand console button for one number change with each button push ... you will probably have to go around by continual pushing and then continue to 1055 ... it continues and returns to 1000 after a few pushes ... i.e., an endless loop). Then monitor and adjust as needed.

1055 corrects by 5.5% (reduces the optimistic numbers). (I know, it seems backwards to me, too.)

E55AMG2 · 9th January 2009, 06:57

1000 works fine for me...but Jclyman is right. Make sure you're using the correct units then mess with the setting.

SCM5 · 9th January 2009, 07:43

Thanks guys, looking into it now.

Too bad I'm not REALLY getting 31fwy, 21 mixed (mostly city) like the computer said. Our cars would be even more amazing.

RichardP · 9th January 2009, 11:09

The test is number 20, not 17.

jclyman · 9th January 2009, 14:40

Quote:

Originally Posted by SCM5

Thanks guys, looking into it now.

Too bad I'm not REALLY getting 31fwy, 21 mixed (mostly city) like the computer said. Our cars would be even more amazing.

That mileage sounds suspiciously HIGH to me.

While many of us would LOVE to get that mileage, it isn't very likely.

Also, be sure you are driving your M5 like is should be. Like it is stolen or very close to that. These are NOT your grandma's cars.

jclyman · 9th January 2009, 14:42

Quote:

Originally Posted by E55AMG2

1000 works fine for me...but Jclyman is right. Make sure you're using the correct units then mess with the setting.

Are you running oversize tires? Most M5s (factory settings) are running about 5% high, computer vs. computed mileage.

The computer mileage may be even more in error, if you are forced by the government to run some Ethanol in your gas.

E55AMG2 · 9th January 2009, 21:42

Quote:

Originally Posted by jclyman

Are you running oversize tires? Most M5s (factory settings) are running about 5% high, computer vs. computed mileage.

The computer mileage may be even more in error, if you are forced by the government to run some Ethanol in your gas.

I run rears all the way around with the OEM factory size. My guess is the fact that I've got the conforti shark, headers, etc...IIRC, it's reading about .2mpg high.

RichardP · 9th January 2009, 22:15

With Test 20 set at 1000 my MPG is consistently 5.5% optimistic, I've set the value to 1055 and am currently testing that.