BMW cylinder calibration parameters

Long-term fuel correction is a numerical parameter, and its numerical range is -23% ~ 16%. The long-term fuel correction comes from the short-term fuel correction value, which represents the long-term fuel supply correction. 0% means that the air-fuel ratio commanded by PCM can remain unchanged if the fuel supply does not need compensation. If it is significantly lower than 0%, it is negative, indicating that the system is too rich, and the fuel supply should be reduced (reducing the fuel injector pulse width).

If it is significantly higher than 0%, it is a positive value, indicating that there is over-dilution, and PCM should increase the fuel quantity (increase the pulse width of the injector) to compensate. Because long-term fuel fine-tuning follows short-term fuel fine-tuning as much as possible, the negative value caused by idling carbon canister cleaning is not unusual. The maximum allowable value of PCM control for long-term fuel regulation is between -23% and 16%, and the maximum allowable fuel regulation value indicates that the system is too rich or too lean.