Misfire Detection

Misfire Detection:

Misfire detection, whether from mechanical or electrical defects is also monitored as on other M5.2 systems. One sensor is used on the M62 engine which is mounted on the bell housing. The trigger wheel is incorporated onto the flywheel/flexplate and contains 58 teeth with a gap of two missing teeth as on the M73 engine.

To identify misfiring, the control module essentially divides the flywheel into four equal segments according to the time between ignition firings.

Each segment is monitored from ignition firing to ignition firing.

If all cylinders are firing equally, the rotational time between segments is the same.

If a malfunction occurs, the rotational duration for a segment increases. The control module interprets this as a misfire. when the threshold for time difference is exceeded, the fuel injector for the affected cylinder is shut OFF and a fault is logged in the memory.