Automotive Fuel and Emissions
Federal regulations require the OBD II system to turn on the MIL when the emission output is _______ times the federal test procedure.
1.5
In what year did the exhaust gas recirculation (EGR) first appear on vehicles' emission systems?
1972
In what year did the catalytic convertor first make its appearance on automobiles' emission control systems?
1973
As of the year ________, all vehicles must meet the on-board diagnostics II (OBDII)standard.
1996
When testing a catalytic converter equipped with an air-fuel ratio sensor, a reading above ______ indicates a lean mixture.
3.3 V
The ________ of a secondary air injection system pumps air into the exhaust stream and assists the operation of catalytic converter.
Air pump
Identify the exhaust that represents an overly rich air-fuel mixture:
Black
A white colored exhaust can be caused due to a(n) ________.
Blown head gasket
Exhaust with a(n) _______ represents oil that is being burned in the combustion chamber.
Bluish tint
A vehicle is diagnosed for abnormal exhaust smoke. Tech A states that the customer's concern should be verified by starting the engine. Tech B states that this process attempts to duplicate the conditions that the customer described. Who is correct?
Both A and B
A vehicle with an EVAP-related concern is diagnosed. Tech A states that a scan tool can be used to pull any diagnostic codes. Tech B states that if there are no diagnostic codes, the scan tool can be used to view the live sensor and actuator data. Who is correct?
Both A and B
Tech A says that black exhaust indicates a very rich-running engine. Tech B says that white exhaust can indicate coolant in the exhaust. Who is correct?
Both A and B
Tech A says that burning gasoline in an engine creates water as a by-product of combustion. Tech B says that variable valve timing can be used to reduce oxides of nitrogen, eliminating the need for an EGR valve on some engines. Who is correct?
Both A and B
Tech A says that the PCM monitors the pre-cat and post-cat oxygen sensors to determine catalytic converter efficiency. Tech B says that a catalytic converter can be tested by graphing the oxygen sensor readings on a scan tool or lab scope and comparing them. Who is correct?
Both A and B
Tech A says that the purge valve is part of the evaporative emission system. Tech B says that OBD II systems must illuminate the MIL when the emissions exceed 1.5 times the FTP. Who is correct?
Both A and B
Tech A says that the purge valve is part of the evaporative emission system. Tech B says that OBDII systems must illuminate the MIL when the emissions exceed 1.5 times the FTP. Who is correct?
Both A and B
Tech A states that asking a customer if the abnormal exhaust issue happens when the engine is cold or hot will help diagnose the problem accurately. Tech B states that it is important to ask the customer if the engine overheated recently. Who is correct?
Both A and B
Tech A states that contaminants prevents the exhaust gases from interacting with the catalyst converter. Tech B states that lead and silicone contamination cannot generally be cleaned from the catalyst. Who is correct?
Both A and B
Tech A states that engines ping under moderate and heavy loads. Tech B states that a vehicle is likely to ping when climbing a hill or pulling a heavy load. Who is correct?
Both A and B
Tech A states that the gas cap in an EVAP system is prone to leaks. Tech B states that this can be due to the gas cap not being tightened properly. Who is correct?
Both A and B
Tech A states that valves and solenoids are used to control the flow of vapors into and out of the charcoal canister. Tech B states that valves and solenoids are used to direct the vapors into the engine depending on operating conditions. Who is correct?
Both A and B
The _______ back pressure EGR valve uses two diaphragms to operate.
Both A and B
Tech A says that the exhaust gas recirculation (EGR) valve does not function at idle. Tech B says that the EGR valve will not function during wide-open throttle (WOT). Who is correct?
Both Techs A and B
Tech A says that the two-way catalytic convertor was the first type of catalytic convertor designed. Tech B says that it converts hydrocarbons and carbon monoxide to carbon dioxide and water. Who is correct?
Both Techs A and B
_______ is a by-product of complete combustion, along with water.
Carbon dioxide
In older secondary air injection systems, the air distribution hoses to the exhaust manifold required the use of a _______.
Check valve
In a secondary air injection system, ________ prevent exhaust flow back into the air pump.
Check valves
Gas cap leaks are detected by the ________, a code is set, and the MIL turned on.
EVAP monitor
Which of the following ensures that hydrocarbons are not released into the atmosphere when fuel in the fuel tank begins to vaporize and build pressure?
EVAP system
The _______ system recirculates some of the inert exhaust gases back into the intake manifold when combustion temperatures are high enough to create oxides of nitrogen.
Exhaust gas recirculation
Any vehicle produced after 1996 monitors catalyst efficiency by using one oxygen sensor.
False
One strategy in controlling emissions is to closely control the air fuel mixture under specific driving conditions, thereby minimizing emission output.
False
The evaporative emission (EVAP) system is designed to ensure that hydrocarbons are released into the atmosphere.
False
The single-diaphragm EGR valve has a single, spring-loaded diaphragm that seals off the spark plug.
False
The EPA requires every manufactured power train to pass a ________ before it can be sold in the United States.
Federal Test Procedure (FTP)
Carbon monoxide is a colorless, odorless, tasteless, ________, and highly toxic gas.
Flammable
When diagnosing EVAP-related concerns, the _______ can give a good indication of the conditions that set the diagnostic code.
Freeze-frame data
There are two primary pre-combustion emission control systems: the _______ system and the _______ system.
Heated air intake; exhaust gas recirculation
The secondary air injection system consists of all of the components EXCEPT:
Heater core
_______ is created when raw fuel evaporates into the atmosphere or when it does not burn at all in the combustion chamber and is exhausted out the tail pipe.
Hydrocarbons
If the EGR valve of a vehicle is stuck in an open position, the engine will ________.
Idle excessively rough
Which of the following uses oxygen sensors to measure the level of gases in the exhaust stream?
Idling five-gas test
As the air fuel ratio moves away from the stoichiometric point, the hydrocarbons and carbon monoxide emissions ______.
Increase
What will happen if the PCM of a vehicle richens up the fuel mixture due to improper air injection in the exhaust manifold?
It creates more emission.
Which of the following is a function of the positive crankcase ventilation (PCV) system?
It directs blowby gases and vapors back into the intake manifold.
The first step of diagnosing PCV related concerns include _______.
Locating the PCV valve
Choose the correct statement with respect to the exhaust gas recirculation system.
Most PCM-controlled EGR systems incorporate a feedback loop, called a monitor, to ensure that the valve is working properly and EGR gases are flowing in the system.
Tech A says that allowing hot exhaust gases into the engine through the EGR valve helps to warm up the engine during warm-up. Tech B says that rich fuel mixtures create low amounts of carbon monoxide. Who is correct?
Neither A nor B
Tech A states that overheated catalysts cannot be restored and must be replaced. Tech B states that overheated catalysts can be easily restored by driving the vehicle for an extended time under a moderate load. Who is correct?
Neither A nor B
Which of the following is a nonharmful emission?
Nitrogen
Excessive valve stem-to-guide clearance in a vehicle will lead to _______.
Oil being burnt in the combustion chamber
When sulfur burns in the combustion chamber, ________ sulfur molecule(s) combine(s)with ________ oxygen molecule(s), creating sulfur dioxide.
One; two
The three regulated emissions the three-way catalytic converter is designed to convert are carbon monoxide, hydrocarbons, and ________.
Oxides of nitrogen
Under the high temperature and pressure of combustion, nitrogen may combine with oxygen to produce ________.
Oxides of nitrogen
If the EGR valve of a vehicle is stuck in a closed position, pinging can result, along with excessive ________.
Oxides of nitrogen emissions
What DTC will be set by the PCM if the ECM detects a small leak in the EVAP system?
P0456
Identify the system that is used to remove blow-by gases from the crankcase in an environmentally friendly manner.
PCV system
Oxides of nitrogen are claimed to be major contributors to ________, along with hydrocarbons and sunlight.
Photochemical smog
A drivability concern caused by an EGR valve is called _______ and is a pre-ignition or detonation concern.
Pinging
_______ systems stop the release of hydrocarbons from the crankcase of the engine to the atmosphere.
Positive crankcase ventilation (PCV)
What will happen if blowby gases are not removed from the crankcase of a vehicle?
Pressure build up can occur
In the combustion chamber where surface temperatures are low, the combustion flame can be ________.
Quenched
When the catalyst of a catalytic converter is contaminated with lead and silicone, then the converter must be typically _______.
Replaced
The ________ effect occurs when the exhaust gases moving out of the combustion chamber create a low-pressure area in the exhaust manifold, helping to pull air and fuel into the cylinder.
Scavenging
The ________ type of PCV system is used on turbocharged applications because turbocharged systems pressurize the intake system and would close off a standard PCV valve.
Separator
In vehicles with cracks and leaks that result in an EVAP system failure, the use of a(n) _______ may be necessary to find the leaks in the system.
Smoke machine
There are two common types of electric EGR valves: the pulse-width-modulated solenoid type and the _______ motor EGR valve type.
Stepper
Tech A says that carbon monoxide is partially burned fuel. Tech B says that oxides of nitrogen are unburned fuel. Who is correct?
Tech A
Tech A says that the EVAP system stores escaping hydrocarbons until the engine can burn them. Tech B says that catalytic converters were designed for regular leaded gas. Who is correct?
Tech A
Tech A states that a visual inspection of the hoses and components of an EVAP system may give clues as to the cause of a fault. Tech B states that only a scan tool can will help diagnose the cause of faults in an EVAP system. Who is correct?
Tech A
Tech A states that if air is not injected into the exhaust manifold when the engine is cold, the hydrocarbons and carbon monoxide emissions will be excessive. Tech B states that air injection in the exhaust manifold when the engine is cold will increase hydrocarbons and carbon monoxide emissions. Who is correct?
Tech A
Tech A states that if the EVAP system continues to purge at idle, a rough idle could be created. Tech B states that even a small fault in the EVAP system creates drivability issues. Who is correct?
Tech A
Tech A states that the possible causes of an abnormal exhaust smoke can be researched in the appropriate service information. Tech B states that applicable TSB's most likely list the possible causes of an abnormal exhaust. Who is correct?
Tech A
Tech A states that to diagnose abnormal exhaust color, it is important to understand what each color represents. Tech B states that the color of an exhaust cannot help diagnose abnormal exhaust. Who is correct?
Tech A
Tech A states that understanding the customer's complaint is the first stage of diagnosing an abnormal exhaust. Tech B states that a visual inspection is the first stage of diagnosing an abnormal exhaust. Who is correct?
Tech A
Tech A says that hydrocarbons are a result of complete combustion. Tech B says that a catalytic converter creates a chemical reaction, changing carbon monoxide and hydrocarbons to water and carbon dioxide. Who is correct?
Tech B
Tech A says that the EGR valve is open fully at idle so that the engine will not die. Tech B says that oxides of nitrogen are created in large amounts when the combustion temperature is above 2500°F (1400°C). Who is correct?
Tech B
Tech A says that the PCV system recirculates exhaust gases into the intake manifold. Tech B says that the PCV system recirculates blowby gases into the intake manifold. Who is correct?
Tech B
If the vapor line between the charcoal canister and the fuel tank is ruptured, _______.
The MIL will probably be illuminated
When removing the PCV valve, a strong vacuum coming through the valve with the engine running ensures that _______.
The PCV valve and hose are clear
Carbon dioxide is a good indicator of whether the fuel is burning completely.
True
For fuel to burn efficiently, it needs to be fully evaporated and completely mixed with the right proportion of air.
True
Ozone blocks harmful ultraviolet light from the sun in the upper atmosphere.
True
Repeat engine oil leaks may be the result of excessive pressure in the crankcase.
True
The refining process used to reduce the sulfur level can reduce the natural lubricating properties of the diesel fuel.
True
The first step in controlling engine emissions is to design the engine in such a way as to reduce emissions as much as possible, such as building ________-enhancing strategies and precisely controlling valve and spark timing.
Turbulence
In a ________ type of PCV system, a replaceable, spring-loaded PCV valve regulates gas flow.
Variable-orifice
The catalytic converter of a secondary air injection system converts the hydrocarbons and carbon monoxide to _______ and _______.
Water, carbon dioxide
In which of these cases is the catalytic converter most likely to be saved?
When contaminated by carbon
Identify the exhaust that represents water or coolant burning in the combustion chamber:
White
A diaphragm-style EGR valve can experience all of the following concerns, EXCEPT:
a MAP sensor could read incorrectly.
Black exhaust represents:
an overly rich air-fuel mixture.
All of the following conditions lead to a black colored exhaust, EXCEPT:
blown head gasket.
The vent and purge solenoids of an EVAP system can fail due to all of the following reasons EXCEPT:
if the valves are affected by an improperly tightened gas cap.
The reduction catalyst in a catalytic converter helps to:
reduce the oxides of nitrogen molecules into their base compounds.
All of the following conditions lead to an exhaust with bluish tint, EXCEPT:
rich air-fuel mixture.
All of the following are sources of emissions from current gasoline-fuelled motor vehicles except:
the HVAC system.
The EPA requires that the malfunction indicator lamp (MIL) turn on and one or more specific diagnostic trouble codes (DTCs) be set in memory:
when emissions are 1.5 times the FTP limit.
Physical damage to a catalytic converter can occur under all of the following conditions EXCEPT:
when the catalyst is coated by silicone from improper sealants.
