Quote:
Originally Posted by Weiner0123
Do you think I could have been tricked about this "environmental recall" I noticed a significant decrease in power after I serviced it for the recall.. I ordered the vehicle in February so I got a really early production model... I wonder if I got duped
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Thanks a lot for sharing this letter, it explains what all this hoopla about the 'power lost' is about.
Here in the US, there is no emission standards at full throttle (85%+). This exception was made so car manufactures could deliver maximum power when it is needed the most and the overall effect on emissions would be small, since people rarely drive at full throttle.
Thus, at high RPMs, the O2 sensors go into an "open loop" state and is taken out of the system so the fuel system can be enriched for maximum power, without the needed to abide by any federal emission standard, since it's exempt.
It seems in the early M340i, the ECU mapping was programmed in error to place the O2 sensor in a "open loop" state at lower power band, instead where it belong, at WOT.
This new software update places the power back in the higher RPM to meet allowed emission standards. So the addition power wasn't taken away, it was just move to higher band in the RPM.
This aftermarket tune just brings back original lower end power band.