m50 swap into 325i with full obc, has obc issues

[oh2fly]

Has anyone connected their obc to the m50 ecu and got their fuel mileage, and range to work? I have tried a couple different ways and get a range of 500 plus miles and way too unbelievable gas mileage. Goes to 99.9 mpg on decel and 30 plus while cruising. It can't be that good. :shock:

[Addissimo]

Its been discussed here

http://www.r3vlimited.com/phpBB2/viewtopic.php?t=17319

[oh2fly]

Thanks. I just read it but it seems others have the same optimistic mileage problem as I do without an answer.

[clutterbucker]

Fill up, reset your odometer, drive around, fill up, long division.
I'm willing to bet that your gas mileage really is that good. When you put the newer sixes in these little cars, they don't have to work so hard to drag the car around. Just a theory of mine.

Congrats.

[Bryson]

it's due to the different sized injectors than what the OBC is calibrated for. It bases its fuel use off of duty cycles, and a 17lb injector at 80% duty puts out much more fuel than a 13lb injector at 80% duty. This means that you're using fuel at 80%@17 while your OBC thinks you are using at 80%@13.
There is no known fix for this yet
I hope that's understandable. The instantaneous fuel economy gauge will read the same amount off, as will the range of your tank.

[clutterbucker]

^sounds like you should listen to him, not me^

but still, I want to know what kind of milage you're actually getting....reset the odometer, fill up, and run it down just below 1/4...divide the numbers. I've heard of people getting civic-like gas mileage with even S50s.