Oxygen Sensor: Description and Operation

This is a self-adjusting engine control system designed to reduce emissions and improve fuel economy. An exhaust gas sensor (oxygen sensor or lambda sond), monitors the oxygen content in the exhaust gases. The exhaust gas measurements are fed into a computerized engine control system, which continuously adjusts the fuel injection system for an optimum air/fuel ratio. This provides the optimum condition for best fuel economy and the elimination of major pollutants by a three-way catalytic converter. Fig. 33.

IMPORTANT!
Small amounts of lead are sufficient to damage the lambda sond. Always use unleaded gasoline.

Fig. 34 LAMBDA SOND (NON HEATED):

Fig. 35 LAMBDA SOND (HEATED):

LAMBDA SOND (OXYGEN SENSOR)
Measurements are taken by a ceramic sensor in the lambda sond. It produces a small voltage (90 - 100 mV, or 0.9 - 1.0 V) in proportion to the difference between the oxygen content of the exhaust and the oxygen content in the air. The exhaust gases (non heated sensor) or an electrical heating element (heated sensor) in the lambda sond will heat the sensor to its operating temperature of 350°C (660°F). The lambda sond is located in the exhaust system upstream of the catalytic converter. Fig. 34. and Fig. 35.

NOTE:
There are two different types of lambda sonds used for the 1984 model year, a heated or unheated version. They can be identified by the amount of electrical wires at the sond.
One wire to the lambda sond : non heated lambda sond
Three wires to the lambda sond : heated lambda sond