ICQ>9445373

This is from Bosch information"

Test for a rich mixture as follows:

a. Disconnect the sensor lead to the control unit.

b. Run the engine at 2500 rpm

c. Artificially enrich the fuel mixture on electronic fuel injected engines by removing and plugging the vacuumn line to the fuel pressure regulator.

d. If the voltmeter rapidly reads .9 volts, then the oxyben sensor is correctly sensing a rich mixture. But, if the voltmeter responds sluggishlly, or if it stays below .9 volts, then the sensor should be replaced.

Test for a lean mixture as follows:

a. Induce a small vacuum leak.

b. If the voltmeter rapidly drops to .2 volts or below in less than a second, then the oxygen sensor is correctly measuring the lean mixture. But if the voltmeter responds sluggishly, of if it stays above .2 volts, the the sensor should be replaced.

Test dynamic performance as follows:

a. Reconnect the sensor lead.

b. Set the mixture to specification.

c. Run the engine at 1500 rpm.

d. The sensor output should fluctuate around .5 volts. If it doesn't, replace the sensor.