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<E34>OBC MPG Misreadings - revisited

Like Gunnar Elmgren in n.147 and others I have followed the FAQ to adjust the
reading for MPG on my OBC.  My problems started after the installation of the
3rd replacement motherboard for my instrument cluster (that's another story).
 Following the replacement my MPG reading shot up so that it was over 4 more
mpg than actual.  The correction factor in my OBC at the time was "1000".
 Using the formula in the FAQ I too needed to change the factor to something
less than "0750" which the OBC would not accept.  I then started
experimenting with a number higher than "1000".  By a process of
interpolation I finally ended up with a final factor of "1115" which now
gives me an OBC reading that exactly matches my actual MPG. It took me 4 fill
ups of gas and four adjustments of the factor but it is now correct.  All
this suggests that I did not read the FAQ correctly or that the relationship
of the correction factor is an inverse one rather than a direct one as
exressed in the FAQ.

The bottom line is that everyone can have a correct OBC MPG reading.  If
anyone else on the digest has additional information on this fun problem I
hope you will share it with us.

Regards:

Fred Meloan
BMW CCA 86321 NCC
1989 E34 525i
Maryland tag "FDM"