Misfire Monitor - Mitsubishi Eclipse Technical Information Manual

Misfire Monitor

Background
Misfire is defined by the California Air Resources
Board as the lack of combustion in a cylinder due
to absence of spark, poor fueling, compression,
or any other cause. As a result, the air/fuel mixture
will not burn, and during the exhaust stroke, it enters
the exhaust system. The raw fuel and excess oxygen
adversely affect the fuel system's feedback mecha-
nism (the oxygen sensor) and can cause permanent
damage to the catalytic convertor.
ENGINE <NON-TURBO> - Control System
Crank signal
Operation
The OBD II misfire monitor uses information pro-
vided by the crank position sensor to determine
engine rpm and detect slight variations due to engine
misfire. Crankshaft rpm is calculated between the
sensor signal.
2 revolutions
60" reference notch