405 L4-1905cc 1.9L (1989)
Oxygen Sensor: Description and Operation
Oxygen Sensor (Lambda Sond)
PURPOSE
The oxygen sensor measures the oxygen content in the exhaust and sends a voltage signal to the ECU.
LOCATION
The oxygen sensor is mounted in the exhaust manifold.
CONSTRUCTION
The sensor consists of a steel housing, heating stem (element), sensor tip and its protective sleeve. The sensor tip itself is made from a platinum
covered zirconium-oxide pipe.
OPERATION
The oxygen sensor a "comparing oxygen sensor". It produces a measureable voltage by comparing the amount of oxygen in the exhaust gas with
the amount in the ambient air.
The sensor operates only within a temperature range of approx. 545 - 1530°F (285 - 850°C). It is electrically heated to reach its operating
temperature as fast as possible. When the ignition is turned ON, current is sent to the PTC (positive temperature coefficient) resistor (heating stem)
whose resistance increases as temperature increases.
Exhaust gases reach the outer surface of the oxygen sensor tip via the openings in the protective sleeve. Ambient air reaches the sensor's inner
surface via channels. The differance in oxygen content produces a voltage read by the ECU.
