CataClean Global Ltd. - High Emissions Readings?

High Emissions Readings?

Diagnosis
Diagnosis of high emissions can be an involved process that usually requires special tools and measuring equipment. However, armed with a test report indicating what gases are high can help you determine what systems may not be functional.

If the vehicle has failed as a result of high CO and HC, the CO failure should be diagnosed first. If the "Service Engine Soon" or "Check Engine" light is on it should be diagnosed prior to any emissions diagnosis. CO Failure is the result of an excessively rich air fuel mixture.

The following is a list of the most common causes:

Defective Oxygen Sensor
Inoperative Air Injection System (if equipped)
Leaking or defective Fuel Injectors
Restricted air filter (especially if high CO is present only at high RPM)
Vacuum leaks resulting in improper MAP sensor operation
Defective air mass or air flow sensor
Malfunctioning fuel evaporation system or purge valve
Defective Catalytic Converter
Defective thermostat (cooling system), thermostat stuck open
Oil contaminated with fuel, excessive miles between oil changes

HC Failure is the result of incomplete combustion. Any item that causes incomplete combustion can result in high HC.

The most common causes are:

Worn spark plugs
Defective spark plug wires
Worn distributor cap and/or rotor
Improper ignition timing, usually over advanced
Vacuum leaks
Engine mechanical failure, low compression, worn valves, excessive oil consumption

NOX Failure is the result of combustion temperatures that are too high.

The most common causes are:

Inoperative Exhaust Gas Recirculation System (EGR)
Cooling system malfunction, engine running too hot (restricted radiator, defective thermostat, etc.)
Over advanced ignition timing
Excessively lean air fuel mixture (defective oxygen sensor, MAP sensor or Air Mass Sensor)