B250 3/4 Ton Van V8-318 5.2L VIN T FI (1992)
Oxygen Sensor: Description and Operation
O2 Sensor Cutaway View (Typical)
LOCATION
The heated oxygen sensor is located in the exhaust pipe in front of the catalytic converter.
PURPOSE
The Engine Controller uses input to fine tune air/fuel mixture. This is done by varying injector pulse width (on time).
OPERATION
The oxygen sensor is a voltage generating device. A voltage signal (0-1 volt) is generated by comparing the difference in oxygen content between
the exhaust gases and outside air. The higher the difference (rich mixture, low exhaust oxygen content) the higher the voltage generated by the
oxygen sensor. Smaller differences (lean mixture, high exhaust oxygen content) result in a lower voltage being generated.
The oxygen sensor has a heating element that maintains proper oxygen sensor operating temperature at all times. This process allows the vehicle to
enter closed loop at an earlier time and to remain in closed loop during the remainder of the operating cycle. The oxygen sensor heating element
receives voltage from the fuel pump relay.
During CLOSED LOOP operation, the engine controller monitors the signals it receives from the oxygen sensor, and other sensors, and uses these
signals to adjust the injector pulse width according to the current driving condition.
During OPEN LOOP operation, the engine controller ignores the oxygen sensor's signals, and other sensor's signals, and adjusts injector pulse
widths according to preprogrammed specifications in the controller.
