Oxygen Sensor
WARNING: This page does not describe the selected car, but rather 9 other vehicles, including the 1985 Ford Ranger, 1985 Ford RV Cutaway, 1985 Ford Pickup, 1985 Ford Econoline, and 1985 Ford Cutaway. However, it is still accessible from the selected car via links, so may be relevant.
This sensor is threaded into exhaust manifold where it constantly monitors oxygen content of exhaust gases. A voltage signal is produced which varies according to difference in oxygen content between exhaust gases and surrounding atmosphere. This signal is sent to the ECA which translates exhaust gas oxygen content to air/fuel ratio. It then alters air/fuel ratio to hold the ideal ratio for current engine operating conditions.