Week 14 Quiz Study Guide

Technician A says CO emissions increase as the air/fuel ratio becomes richer. Technician B says CO emissions increase as the air/fuel ratio becomes leaner. Who is correct?

A only

A restricted catalytic converter may cause ______.

All of the answers are correct.

The OBD-II EGR system monitor tests the functioning of the EGR system by opening the EGR valve while monitoring the change in ________.

All the answers are correct

Which of the following conditions may result from too little EGR flow?

All the answers are correct

Technician A says if the EGR valve does not open, the engine may emit excessive amounts of HC. Technician B says if the EGR valve does not open, the engine may detonate on acceleration. Who is correct?

B only

Crankcase pressure forcing crankcase gases through the clean air hose and into the air cleaner is being discussed. Technician A says the cause may be an excessive amount of blowby. Technician B says the cause may be a restricted PCV valve. Who is correct?

Both A and B

Technician A says a defective PCV valve rough idle operation. Technician B says the PCV system depends upon a properly sealed engine to perform correctly. Who is correct?

Both A and B

Technician A says a pressure gauge can be inserted into the oxygen sensor bore, and back pressure caused by the catalytic converter can be measured. Technician B says a vacuum gauge can be used to identify a restricted converter. Who is correct?

Both A and B

Technician A says when CO goes up, O2 goes down. Technician B says that at the stoichiometric ratio, HC and CO will be at their lowest levels and CO2 will be at its highest. Who is correct?

Both A and B

Before the EVAP system on an OBD-II vehicle can be pressure tested or smoke tested for leaks, a scan tool must be used to _____.

Close the canister vent solenoid

Technician A says a defective throttle position sensor will not affect the EGR valve operation. Technician B says a defective engine coolant temperature sensor will not affect the EGR valve operation. Who is correct?

Neither A nor B

To monitor the vapor purge in most systems, the PCM changes the duty cycle of the purge solenoid while monitoring the ______.

STFT

A stuck open EGR valve could cause ______.

Stalling

(T/F) A catalytic converter can be tested by measuring the inlet and outlet temperature.

True

(T/F) If the PCV valve is stuck in the open position, a lean air-fuel ratio may cause a rough idle or engine stalling.

True

A PCV valve that is stuck closed or a restricted hose can cause an accumulation of moisture or sludge in an engine.

True

Another term for detonation is spark knock.

True

Excessive Oil consumption can be caused by a plugged PCV hose.

True

Low CO indicates a lean mixture; as the mixture becomes more lean, HC increases.

True

Poor EGR gas flow can cause detonation.

True