Service Manual

WEICHAI EMISSION-RELATED INSTALLATION INSTRUCTIONS
- Attempt to achieve rapid heating-up of the exhaust pipes in the area in front of the sensor.
The exhaust pipe in front of the sensor should not contain any pockets, projections, protruding or
edges etc. to avoid accumulation of condensation water. A downside slope of the pipe is
recommended.
- The use of a sensor type with double protection tube can give a better protection of the sensor
ceramic against condensation water drops. In this case make sure, that the front hole of the double
protection tube does not point against exhaust gas stream.
System measures:
- Never switch on sensor heating before engine starting.
- Delayed switch-on or power control of the sensor heater (e.g. as a function of engine and ambient
temperature), so that the maximum allowed ceramic temperature is not exceeded when there is
condensation water present.
Installation angle should be inclined at least 10° towards horizontal (electrical connection upwards), thus
preventing the collection of liquids between sensor housing and sensor element during the cold start
phase. Other installation angles must be inspected and tested individually.
Avoid inadmissible heating up of the sensor cable grommet, particularly when the engine has been
switched off after running under max load conditions. The use of cleaning/greasing fluids or evaporating
solids at the sensor plug connection is not permitted. Assemble with high temperature resistant grease
on the screw-in thread. Tightening torque: 29.5ft-lb ~44ft-lb (40Nm~60Nm), material characteristics and
strength of the thread must be appropriate. Recommended material for the thread boss in the exhaust
pipe is temperature resistant stainless ferritic steel, e.g. X 5 CrNi 18 9, DIN 17440 1.4301 or 1.4303 or
SAE 30304 or SAE 30305 (US standard)
The sensor’s protection tube must protrude completely into the exhaust-gas flow.
Figure 15 TWC and Post HEGO Sensor Installation
There is to be no possibility of the sensor protection tube contacting the opposite side of the exhaust
pipe. A waterproof electrical connector’s version is required.
WEICHAI & PSI SERVICE MANUALS AVAILABLE ONLINE AT FLYPARTSGUY.COM
GET YOUR WEICHAI & AFTERMARKET SERVICE PARTS AT FLYPARTSGUY.COM