Oxygen Sensors - Westerbeke 6.5 SBCG-60HZ Service Manual

COMPONENT TESTING
TESTING OXYGEN SENSORS
Two oxygen sensors are used in the EFI system. A narrow
band sensor on the exhaust inlet side of the catalyst and a
wide band sensor on the exhaust discharge side of the cata-
lyst. These sensors monitor engine operation that the ECU
interprets and adjusts air/fuel ratios accordingly.
TESTING THE OXYGEN SENSORS IN A STATIC
MODE
Narrow .Band Sensor: Unplug the sensor from the engine
harness. LoCate the 2 white pin leads, measure across these
two pins with an ohm meter.
Resistance Value 2.0 - 4.0 OHM (approximately)
There should be no continuity between either of the two
white lead pins and the black or grey lead pins.
Wide Band Sensor:
Unplug the sensor from the engine
harness. Locate the red pin lead and the vacant black pin
lead. Measure across these two pins with an ohm ll!-eter.
Resistance Value 110.0 - 130.0 OHM (approximately)
No continuity should be found between these two pins and
any of the other four.
Sensors not meeting these tests are presumed faulty. care
should be taken when installing a replacement sensor. Do not
scratch, damage, or handle the sensor end in any way.
TESTING RESISTANCE
NARROW BAND SENSOR
PN:049076
23
TESTING RESISTANCE
WIDE BAND SENSOR
PH:049077