Engine Controls - Oxygen Sensor Description & New Torque
86nissan06Models All Models (1982-1987)
Section Emission Control
Classification EC86-010
Bulletin No. TS86-128
Date July 11, 1986
EXHAUST GAS SENSORS, ALL MODELS
SERVICE INFORMATION
Starting with the 1986 Model Year, two types of exhaust gas sensors have been used on Nissan vehicles. In addition to the previously used Zirconia type sensor, some 1986 and 1987 vehicles are now being manufactured with Titania type sensors. This bulletin contains a description of these sensors and a model application chart for your reference.
In addition, the tightening torque for exhaust gas sensors has been standardized. This revised torque information follows the appropriate model application chart. Please make note of the new torque by hand in the Tightening Torque Table of the EF&EC S.D.S. Section of the appropriate model Service Manual, if necessary.
I. ZIRCONIA TYPE EXHAUST GAS SENSOR The exhaust gas sensor, which is placed into the exhaust manifold, monitors the mount of oxygen in the exhaust gas. The sensor has a closed-end tube made of ceramic zirconia. The outer surface of the tube is exposed to exhaust gas, and the inner surface to atmosphere. The zirconia of the tube compares the oxygen density of exhaust gas with that of atmosphere, and generates electricity. In order to improve generating power of the zirconia, its tube is coated with platinum. The voltage is approximately 1V when the mixture ratio is richer than the ideal air-fuel ratio, and approximately OV when leaner. The radical change from 1V to OV occurs near the ideal mixture ratio. In this way, the exhaust gas sensor detects the amount of oxygen in the exhaust gas and sends the signal of approximately 1V or OV to the E.C.U. On 1984-1985 300ZX and 1985-1986 Maxima models, with VG30 engines a ceramic heater was employed to ensure the stable performance of the sensor.
Make note of this new torque information in the Tightening Torque Table, EF&EC Section of these model Service Manuals.
II. TITANIA TYPE EXHAUST GAS SENSOR The exhaust gas sensor, located in the exhaust tube, monitors the amount of oxygen in the exhaust gas. This sensor is made of ceramic titania that is drastically changed by electrical resistance at the ideal air-fuel ratio. The E.C.U. supplies the sensor with approximately 1V and reads the sensor output voltage, depending on its resistance. In order to activate the sensor element, it is equipped with a heater.
Make note of new torque information in the Tightening Torque Table, EF&EC Section of these model Service Manuals.
REMOVAL CAUTION: If the exhaust gas sensor is difficult to remove, use Nissan Rust Penetrant, P/N 999MP-A3020, or equivalent to avoid possible engine damage.