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Re: E36 325i Mileage ( OBC Reads Low )

	I have been recording gas mileage info for the last 2 years
of driving a '92 325i with the OBC. Originally CONSUM1 and CONSUM2
were reset. CONSUM1 is left alone to record overall mileage to date
and CONSUM2 is reset at each fill-up. At each fill-up the CONSUM
values are recorded along with the ODO and the gallons off the pump.
	Some time ago I summarized 26 consecutive fill-ups to find
the overall mileage from the gallons on the pump and the ODO to
compare with the OBC value for CONSUM1. What I found was that
CONSUM1 was 1 MPG lower than the calculator computation. Comparison
of CONSUM2 with the calculator for an individual fill-up shows some
variance but the OBC is either equal to or lower than the calculator
to a max of about -1.6.
	I can only speculate, but perhaps the OBC computes RANGE
based on the same parameters as it does CONSUM 1 & 2 so that
the RANGE is a safe value for you when your nearly out of gas
and wondering how far you have left to go before taking a hike.
	Does anyone know how the OBC knows how much fuel is
being used? Is the fuel gauge that accurate?

Al Cote
[email protected]