Ford Pick-Ups/Bronco 1976-1986 Repair Guide

Oxygen Sensor


See Figure 1

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Fig. Fig. 1: Exhaust gas oxygen sensor

An oxygen sensor is used on most later models and is mounted on the exhaust manifold. The sensor protrudes into the exhaust stream and monitors the oxygen content of the exhaust gases. The oxygen sensor produces a low voltage that is determined by the amount of unburned O 2 in the exhaust. The ECM monitors this low voltage signal and issues a command to adjust for a too rich or too lean fuel mixture.

No attempt should ever be made to measure the output voltage of the oxygen sensor. The current drain of a conventional voltmeter would be such that the sensor would become permanently damaged. No jumpers, test leads, or any other connections should ever be made to the sensor.


The oxygen sensor must be replaced every 30,000 miles (48,000 km). The sensor may be difficult to remove when the engine temperature is below 120°F (48°C). Excessive force may damage the threads in the exhaust manifold or pipe; follow the procedure carefully.

  1. Locate the oxygen sensor. It protrudes from the center of the exhaust manifold and looks somewhat like a spark plug.
  3. Disconnect the electrical connector from the oxygen sensor.
  5. Spray a commercial penetrating oil onto the the sensor threads and let it soak in.
  7. Carefully remove the sensor.

To install:
  1. Coat the new sensor's threads with anti-seize compound made for oxygen sensors. This is not conventional anti-seize paste. The use of regular anti-seize compound may render the sensor inoperative.
  3. Installation torque is 30 ft. lbs. (42 Nm).
  5. Reconnect the electrical connector. Be careful not to damage the connector.