Range And MPG Readings High - The Unofficial BMW M5 Messageboard (m5board.com)

dchyde · 3rd August 2006, 21:03

I have noticed that my MPG reading is about twice what it should be. It says I am getting 28 miles per gallon. Also, when my tank is full the range reads like 900 miles left. As we all know this is not possible on two tanks of gas. Everything else seems to be working OK; speedo, fuel gauge, etc. I wonder if this has something to do with the euro conversion or is there a different fuel tank sensor for the computer that is malfunctioning.

Cyrus · 3rd August 2006, 21:17

Mine's the opposite.

I can drive upto 100 miles on the red. OBC says I never have enough fuel.

You have to accept that these cars are old now and things don't work aswell as they should. Or these particular instruments don't work very well from the offset.

My freinds Alpina B10 V8 always suggests it's doing 10mpg and always has more fuel than indicated.

Same thing on most E30's.

Maybe it's a BMW thing!

Sal

dchyde · 3rd August 2006, 21:20

I guess I am always hopeful for an easy fix. I should know better now.

VentoGT · 4th August 2006, 00:16

Speaking of--how many gallons are the US M5 tanks? I seem to only be able to put in 15.5-16 Gallons when my car is in the red, and I read that some of the e34 cars have 21 gallon tanks...my sender may be off...

GDA · 5th August 2006, 02:33

Quote:

Originally Posted by dchyde

I guess I am always hopeful for an easy fix. I should know better now.

Derek

Fill up your tank completely and then do OBC test number #7. This tells you how many litres you have remaining in your tank. If it registers 80, then in Federalization the OBC got reset with US data. A really good dealer can reprogram the OBC with your Euro coding. Once its back to 90 litres you can refine the actual using the correction factor in test #20.

Look here for the details...

http://bmwe34m5.com/node/231

Oh, probably cost you at least 1/2 hour of master tech time unless you have a VERY friendly dealer....

Greg

dchyde · 5th August 2006, 03:06

Greg,

Thanks for the info. I will give it a try, it won't take long to burn through the rest of my tank.

Cheers,
Derek

dchyde · 8th August 2006, 19:11

Greg,

Filled the tank and ran the test, the obc showed just under 80 litres. You were right on thanks. So I guess I have to get it programmed now. I assume like most of this devices, it has to be flashed with special equipment, there is not a switch or something.

Derek