Summary table of polluting emission tolerances

Summary table of polluting emission tolerances

Checking CO and HC levels at exhaust

Measure carbon monoxide (CO) and uncombusted hydrocarbon (HC) at the exhaust by inserting the probe of a calibrated tester into the end of the exhaust pipe by at least 30 cm as indicated in the figure.

If the shape of the exhaust tail pipe will not allow the probe to be fitted fully, add an extension pipe and ensure the joint area is well sealed.

1. Check that idling CO and HC levels are as specified (see table).
2. If the HC level is not as specified whereas level measured upstream of converter is correct, engine parameters should be considered correct and the cause of the anomaly must lie in reduced converter efficiency.