Fuel System Monitoring

Fuel System Monitoring




Fuel System monitoring is an OBD II requirement which monitors the calculated injection time (ti) in relation to engine speed, load, and the pre catalytic converter oxygen sensor(s) signals as a result of the residual oxygen in the exhaust stream.

The engine control module uses the pre catalyst oxygen sensor signals as a correction factor for adjusting and optimizing the mixture pilot control under all engine operating conditions.

Adaptation Values

-In order to maintain an "ideal" air/fuel ratio, the engine control module is capable of adapting to various environmental conditions encountered while the vehicle is in operation (i.e. changes in altitude, humidity, ambient temperature, fuel quality, etc...).

-The adaptation system can only make slight corrections and can not compensate for large changes which may be encountered as a result of incorrect airflow or incorrect fuel supply to the engine.

-Within the areas of adjustable adaption, the engine control module modifies the injection rate under two areas of engine operation:

1.During idle and low load mid range engine speeds (Additive Adaptation).

2.During operation under a normal to higher load when at higher engine speeds (Multiplicative Adaptation).

Diagnosis Request Status:

These values are displayed in the "Diagnosis Requests" section of the DIS software and is a helpful diagnostic tool that shows how the system is trying to compensate for a less than ideal initial air/fuel ratio.

NOTE: If the adaptation value is greater than "0.0 ms" the Engine control module is trying to en-richen the mixture If the adaptation value is less then "0.0 ms the Engine Control Module is trying to lean-out the mixture.





Associated Fault Codes: Adaptation