PCV system prevents the release of blow by gasses from the engine crankcase to the atmosphere. Which emission does the PCV system reduce?
Which statement is true about early EVAP system?
They were controlled by a ported vacuum source.
EGR system reduces emissions by diluting the air/fuel mixture with a controlled amount of exhaust gas. Which emission is reduced by the EGR system?
Which emissions are reduced by the EFE system?
HC and CO
What emissions are reduced by using an Oxidation Catalytic Converter?
HC, CO, and NOx
Which emissions are reduced by the Air Injection system?
HC and CO
Which system may be used to reduce NOx if an EGR valve is not present?
Variable Valve Timing
While discussing EGR valve operation, Tech A says that the EGR valve opens up fully at wide open throttle. Tech B says maximum EGR flow occurs at cruising speed with a light engine load. Who is correct?
While discussing the proper way to test a catalytic converter, Tech A says a pressure gauge can be inserted into the oxygen sensor bore and backpressure caused by a restricted exhaust or plugged CAT could be measured. Tech B says a Delta Temperature Test may be performed. Who is correct?
While discussing PCV system diagnosis, Tech A says a stuck open PCV valve may cause rough idle operation. Tech B says satisfactory PCV system operation depends on a properly sealed engine. Who is correct?
Excessive HC and CO emissions may be caused by all of the following except
plugged pcv system
inoperative air pump
engine diluted with gasoline
While discussing a PCM controlled evaporative (EVAP) system, Tech A says one condition which has to be met for purging to take place is that the emission system is operating in closed loop. Tech B says the purge control solenoid may be "duty cyled" by the PCM. Who is correct?
While discussing tail pipe emissions, Tech A says CO emissions increase as the air/fuel ratio becomes richer. Tech B says CO emissions will increase if you have an ignition misfire. Who is correct?
While discussing catalytic converter diagnosis, Tech A says a good converter is evident by low amounts of CO2 in the exhaust. Tech B says a restricted exhaust or plugged CAT can be checked by using a vacuum gauge following proper procedures. Who is correct?
Two Technicians are discussing EGR systems. Tech A says a digital EGR valve uses an intake manifold vacuum source for its operation. Tech B says a linear EGR valve has up to three solenoids controlled by the PCM. Who is correct?
digital EGR = 3 solenoid
linear EGR = 1 solenoid
Which fuel delivery system below would NOT use an EFE system?
Port Fuel Injected
Which of the following could contribute to an increase in the levels of NOx?
overly advanced ignition timing
Which is true about EVAP systems?
it can be controlled by the PCM
Which emission is reduced by the EVAP system?
Tech A says the first emissions which were reduced were those caused by "blow by" gasses. Tech B says "blow by" gasses were reduced by the EVAP system. Who is correct?