Deck 24: Engine Performance Systems

Question 1

Higher compression ratios tend to speed up combustion.

Answer 1

True

Question 2

In a GDI system (gasoline direct injection) the injector sprays fuel into the ______.

A) intake manifold (plenum)
B) intake runner in manifold
C) intake port in cylinder head
D) cylinders (combustion chamber)

Answer 2

D

Question 3

Which of the following jobs is NOT a function of the ignition system?

A) engaging the starter motor
B) generating a spark with enough heat to ignite the fuel
C) maintaining the spark long enough for total combustion of air and fuel
D) delivering the spark at the proper time to each cylinder on the compression stroke

Answer 3

A

Question 4

When there is a calibration update available for an OBD-II vehicle, the old EPROM is removed from its socket in the PCM and a new EPROM with the updated software is installed in its place.

Question 5

Which of the following is not a PCM output?

A) solenoids
B) thermostats
C) lights (indicator)
D) relays

Question 6

The PCM can turn off the A/C compressor when the engine is operating at full throttle.

Question 7

Engine vacuum is being discussed. Technician A says that when the engine is operating under light loads, engine vacuum is low. Technician B says that engine vacuum is high when the engine is operated under heavy loads. Who is correct?

A) A only
B) B only
C) both A and B
D) neither A nor B

Question 8

The MIL light should illuminate when the ignition switch is turned to the run position [engine not running] and go out within a few seconds after the engine is started.

Question 9

Which of the following is NOT an advantage of an electronic spark control system?

A) It compensates for changes in engine (and sometimes outside air) temperature
B) It allows lower compression ratio engines to be equally as efficient as higher compression ratio engines
C) It makes changes many times faster than older (mechanical) systems
D) It has a feedback mechanism in which sensor readings allow it to constantly compensate for changing conditions

Question 10

During the EVAP monitor vacuum pull-down test, the canister vent solenoid is held open.

Question 11

Higher-octane fuels are easier to ignite and burn faster than low-octane fuel.

Question 12

Ignition spark typically occurs a few degrees _______.

A) before top dead center [BTDC]
B) after top dead center [ATDC]
C) before bottom dead center [BBDC]
D) after bottom dead center [ABDC]

Question 13

The injector pulse width is ______.

A) the size of the injector nozzle
B) the amount of time the injector opens and sprays fuel
C) the voltage applied to the injector solenoid coil
D) the distance between the injector tip and the center of the intake port

Question 14

Only OBD-II equipped vehicles have a sixteen-pin DLC connector.

Question 15

Air/fuel ratios are being discussed. Technician A says that when the air fuel ratio is higher than 14.7 to 1 the engine produces more power. Technician B says that when the air fuel ratio is lower than 14.7 to 1 the engine uses less fuel. Who is correct?

A) A only
B) B only
C) both A and B
D) neither A nor B

Question 16

OBD-II regulations require all vehicle manufacturers to use the same names and acronyms for all electric and electronic systems related to the engine and emission control systems.

Question 17

Which of the following chemicals is NOT a pollutant?

A) carbon monoxide [CO]
B) oxides of nitrogen [NO_x]
C) nitrogen [N₂]
D) hydrocarbons [HC]

Question 18

The PCM can be electronically linked to other control modules.

Question 19

Port fuel injection systems have a throttle plate assembly, but fuel never passes by the plate.

Question 20

Scan tools can be used to cycle on and off some actuators such as injectors, vacuum solenoids, idle air control motors, and the like.

Question 21

The two types of ignition systems are EI [electronic ignition] and ______.

A) MI [magneto ignition]
B) DI [distributor ignition]
C) MSI [multispark ignition]
D) GCI [ground circuit ignition]

Question 22

Freeze frame data is being discussed. Technician A says erasing the code with a scan tool will erase the corresponding freeze frame data. Technician B says the freeze frame data is the sensor and output status data at the instant the DTC was set. Who is correct?

A) A only
B) B only
C) both A and B
D) neither A nor B

Question 23

Technician A uses the snapshot function of his scan tool to record serial data during a road test that can be transferred and displayed on a PC. Technician B uses the snapshot feature of his scan tool to record the sensor data and conditions leading up to the vehicle setting a DTC. Who is correct?

A) A only
B) B only
C) both A and B
D) neither A nor B

Question 24

EGR monitors are being discussed. Technician A says some EGR system monitors EGR flow by measuring the difference in pressure as the EGR gas flows through an orifice (restriction). Technician B says some EGR monitors measure the temperature of the EGR outlet to determine whether there is gas flowing through the EGR valve. Who is correct?

A) A only
B) B only
C) both A and B
D) neither A nor B

Question 25

Which of the following sensors is NOT used by the computerized ignition system to control ignition timing?

A) oxygen sensor
B) engine temperature
C) manifold vacuum
D) engine RPM

Question 26

When the cylinders are deactivated on a displacement on demand system, _____.

A) half of the cylinders continue to fire normally
B) oil pressure to the hydraulic lifters is increased, pumping up the lifters
C) both the intake and exhaust valves of the deactivated cylinders are held open
D) the injectors continue to fire, but because the manifold vacuum is so low, no fuel flows into the combustion chamber

Question 27

Diagnostic trouble codes are being discussed. Technician A says a P0442 is a manufacturer's code and means different things, depending on what manufacturer built the car. Technician B says that a P0304 code is a universal code that means the same thing no matter what manufacturer built the car. Who is correct?

A) A only
B) B only
C) both A and B
D) neither A nor B

Question 28

A ______________________ or _____________________ increases engine efficiency by forcing (pumping) more air into the cylinders.

Question 29

Data collected by system sensors is stored in _____ memory.

A) RAM
B) nonvolatile RAM
C) ROM
D) PROM

Question 30

On an OBD-II vehicle, the DLC connector is located _____.

A) under the hood, on the left side inner fender
B) under the hood, on the right side inner fender
C) under the hood, in the fuse/relay box
D) under the dashboard, within arm's reach of the driver

Question 31

Before performing any repairs on a vehicle with an illuminated MIL light: Technician A records all DTCs and freeze frame data. Technician B checks for service bulletins.Who is correct?

A) A only
B) B only
C) both A and B
D) neither A nor B

Question 32

Oxygen sensor monitors are being discussed. Technician A says the system monitors the sensor response time as the system cycles lean-rich-lean. Technician B says that at certain times the monitor varies the fuel delivery and checks for heated oxygen sensor response. Who is correct?

A) A only
B) B only
C) both A and B
D) neither A nor B

Question 33

Catalytic converter monitors are being discussed. Technician A says that if the converter is working, the downstream signal frequency should mirror the upstream sensor. Technician B says that the downstream sensor should provide a low-frequency voltage signal. Who is correct?

A) A only
B) B only
C) both A and B
D) neither A nor B

Question 34

Engine operating modes are being discussed. Technician A says that when the engine is in closed-loop mode, the PCM monitors sensor inputs, then adjusts the timing, air fuel ratio, and emission controls. Technician B says the system will switch into open loop when the throttle is fully opened or the oxygen sensors cool down during idle. Who is correct?

A) A only
B) B only
C) both A and B
D) neither A nor B

Question 35

To read flash codes on an OBD I Chrysler-built vehicle ______.

A) connect terminals A and B on the DLC with a jumper wire
B) turn the rotary switch on the PCM counter clockwise 3 clicks
C) connect the E1 and TE1 terminals on the DLC
D) turn the ignition key on and off three times in five seconds, ending in on

Question 36

What sensor is used to detect engine misfire?

A) crankshaft position
B) knock
C) cylinder head temperature
D) exhaust gas temperature

Question 37

Which of the following statements is not true?

A) A type A misfire can cause damage to the catalytic converter if the injector is not shut down
B) A type B misfire will cause the MIL light to flash
C) A type B misfire is set after detected faults in two consecutive drive cycles
D) A type A misfire will set a DTC and cause the MIL light to illuminate immediately

Question 38

The first decision the computer makes in determining the best operating strategy is to determine the _____.

A) throttle opening
B) engine operating mode (cranking, idling, cruise, etc.)
C) outside air temperature
D) barometric pressure

Question 39

A phaser is used to _____.

A) advance or retard camshaft timing
B) measure crankshaft position
C) advance or retard ignition timing
D) kill Klingons

Question 40

Besides the tailpipe, hydrocarbons [HC] can also be emitted from the ____________________.

Question 41

The misfire monitor is necessary protect to the ____________________from melting during a continuous misfire.

Question 42

A fault that comes and goes and is not always present is called a(n) ____________________ fault.

Question 43

All OBD-II vehicles have a minimum of ____________________ oxygen sensors.

Question 44

A catalytic converter monitor DTC is set after detecting faults on ____________________ consecutive drive cycles.

Question 45

What are flash codes?

Question 46

PCM stands for ____________________.

Question 47

The OBD-II system will illuminate the MIL if a failure is detected that will cause the emissions levels to exceed ____________________ times the allowable standards for that model year.

Question 48

The monitor that continuously looks at all the major engine sensors and actuators that can affect emissions levels is called the ____________________.

Question 49

A ____________________ is a snapshot of the activity of the various inputs and outputs at the
time the PCM illuminated the MIL.

Question 50

What is the principal function of the OBD-II system?

Question 51

The ____________________ sensor is used by the misfire monitor to detect excessive misfires.

Question 52

List the steps in diagnosing a vehicle with an illuminated MIL light.

Question 53

The three pollutants found in the exhaust gases are hydrocarbons, carbon monoxide, and ____________________ .

Question 54

All cars built since ____________________ are equipped with an electronic fuel injection system.

Question 55

The output of the upstream and downstream oxygen sensors is compared to determine the efficiency of the ____________________.

Question 56

The ideal or stoichiometric ratio of air to fuel (by weight) is ____________________ in a gasoline engine.

Question 57

List the major components of the fuel delivery system.

Question 58

A PCM that can learn the nominal range of inputs and outputs by monitoring them over a long period of time is said to be using ____________________ strategy.

Question 59

During the secondary AIR active test, the PCM cycles the AIR flow to the exhaust manifold on and off during closed loop operation and monitors the ____________________ voltage and the short-term fuel trim value.

Question 60

After ____________________ warm-up cycles without a fault, a DTC code is erased from active memory, but the DTC and the freeze frame data will be stored as a history code with freeze frame data until it is cleared.

Question 61

What is a type A misfire?

Question 62

What is a type B misfire?

Question 63

What is the DLC and where is it found in modern vehicles?

Question 64

What is the relationship between engine load and manifold vacuum?

Question 65

What is short-term fuel trim?

Question 66

What is the difference between closed loop and open loop engine operation?

Question 67

What is an OBD-II trip?

Question 68

A V-6 engine has an oxygen sensor in each exhaust manifold. How do you determine which one is B1 S1?

Question 69

What is the function of the EVAP system monitor?