Exam 33: Emission Control Systems

During the OBD-II EVAP purge monitor, the duty cycle applied to the purge solenoid is increased. The PCM should see a change in ____________________.

What is the vehicle emission control information (VECI) decal and where is it found?

Diesel engines use a PCV system that is nearly identical to a gasoline engine's PCV system, but is designed for a greater rate of flow.

While discussing EGR systems with a differential pressure feedback EGR (DPFE) sensor, Technician A says the DPFE sensor sends a signal to the PCM in relation to intake manifold pressure. Technician B says the PCM can make corrections to the EGR flow if the actual flow does not match the desired flow. Who is correct?

OBD-II canister purge systems are being discussed. Technician A says the canister purge solenoid valve is only open and controlled when the system is in open loop. Technician B says because the system responds to current engine and operating conditions, the purging of the vapors does not affect drivability. Who is correct?

Port fuel injected engines require intake manifold heating devices.

Technician A says HC emissions are caused by incomplete combustion. Technician B says an excessively lean air/fuel mixture may result in cylinder misfiring and high HC emissions. Who is correct?

Where does a secondary air injection system deliver its air supply when the engine is cold and when the engine is at operating temperature?

The I/M 240 test requires the use of a chassis ____________________.

The two factors that have the greatest effect on vehicle emissions are air/fuel ratio and ___________________ at different spots within the combustion chamber.

Explain why a small PCV valve opening is adequate at idle speed.

What gas has a rotten egg smell and is caused by sulfur in gasoline chemically reacting with air inside the catalytic converter?

Technician A says the back pressure transducer may be incorporated into the design of the EGR valve. Technician B says negative back pressure transducers use the vacuum in the exhaust between pressure pulses to modulate the EGR flow. Who is correct?