Fault Criteria, Emission Related Misfire
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Fault Criteria, Emission Related Misfire
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Misfiring could be due to exhaust emissions exceeding permissible levels.
The number of misfires causing illegal exhaust emissions depends to a certain extent
on engine load and speed.
An engine load and speed dependent matrix in the electronic control module's
memory specifies how many misfires per 1000 engine revolutions are needed for exhaust
emissions to reach an illegal level.
When the conditions for diagnosis are fulfilled, the combustion signals from the ignition
discharge module are evaluated. The fault criteria are satisfied when the number of misfires
per 1000 engine revolutions exceeds the matrix value.
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Ignition timing synchronized
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1.
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Max number of misfires allowed during 1000
crankshaft revolutions.
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2.
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Number of misfires detected ≥ max. number of permissible misfires during
1000 engine revolutions.
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3.
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Combustion signals from the ignition cassette during 1000 crankshaft
revolutions.
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4.
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Fault criteria for catalyst damaging misfire
fulfilled
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