obc programming

Hey,

I have a BMW 325 E2 (i think E36 model). The OBC has a Digital Speed meter (since I put in a code). But the speed on the OBC is 7 km/h lower then on my analog speedometer.

Is there any possible way I can "reprogram" my digital speedometer?

Thanks in advance

Erik

Reply to
Erik Metselaar
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You would do better to reprogram the analogue speedometer, as it's reading high :)

Reply to
Jan Kalin

Your quite right, its to high.

But my analog meter is the same as in every other car, (witch is also to high :-D) so i better reprogram my digital meter

but does any>>>Hey,

Reply to
Erik Metselaar

Check out

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It'sfor 7-series E32, but the OBCs were very similar IIRC.

Reply to
Jan Kalin

Yes the OBC is more accurate than the speedometer, which tends to read high for legal reasons.

7% is a bit much, is the car very new?
Reply to
R. Mark Clayton

Reply to
Erik Metselaar

The SPEED in the OBC is an average over time, and will not track with the actual speed unless the cruise control is set and the speed is not changing.

Set the Cruise to 80 and travel a measured mile -- measured by sign posts outside the car, not with the odometer or trip meter -- and measure the time it takes. If the speedometer is accurate, it will take 45 seconds to go a mile. If 80 is too fast for you, then set the Cruise anywhere you want, and divide 3600 by the time it takes to go the mile, the result will be the speed you are going. Alternatively, divide 3600 by the speed to find the time it should take, then you can see if the mile markers are coming up as expected.

My car is within about 1.5 mph, I have no idea where this falls on the km/h scale. I set the Cruise, time the measured mile, and then use the OBC to confirm the speed. The OBC is within 1.5 of the speedo, and the measured miles fly by at 40 second intervals, give or take a half second.

The OBC is a simple calculation from the speed sensor(s), and should be pretty accurate if the tires are the right size. The speedo uses the same speed sensor input, but the conversion from a digital input to an analog display leaves room for error. You WANT the speedo to read a bit on the high side because if the speedo reads 70 and you are doing 68, you are in better shape than if it reads 70 and you're really doing 73. One way begs for a ticket, the other way assures you won't get a ticket.

Reply to
Jeff Strickland

thanks alot

this article says everything i need to know.

Reply to
Erik Metselaar

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