Service Manual

WEICHAI EMISSION-RELATED INSTALLATION INSTRUCTIONS
PRE-CATALYST OXYGEN SENSOR
Apply an adequate amount of anti-seize compound to the threads of the oxygen sensor and install the
sensor in the O2 sensor port located on the exhaust manifold elbow pipe. Tighten the sensor to the
specified torque 29.5ft-lb ~44ft-lb (40Nm~60Nm). Anti-seize on thread only, don’t put on the sensor.
Figure 14 UEGO sensor installation
POST-CATALYST OXYGEN SENSOR
In general, the sensor installation point must be tested sufficiently by the customer for function and
durability. There shall be no possibility of exhaust leaks upstream of the sensor as exhaust pulsations
can draw in ambient air, leading to erroneous measurements.
Installation in the exhaust line must be at a point guaranteeing representative exhaust gas composition
whilst also satisfying the specified temperature limits. The active sensor ceramic element is heated up
quickly. This means that the sensor installation location must be selected to minimize exhaust-side
stressing with condensation water in order to prevent ceramic element crack. This is helped by locating
the sensor on the outlet of the catalyst assembly.
Design measures:
- Locate sensor as close to the catalytic converter outlet as possible, without exceeding maximum
allowed temperature range
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