engine performance final exam
Each fuel injector has a _____-wire connector.
2
After isolating the high-voltage system, what is the minimum time you should wait before beginning to work on or around the hybrid system?
5 minutes
The compressed hydrogen used in FCEVs (fuel cell electric vehicle) is stored at approximately ______ psi.
5,000
Which of the following is NOT representative of sequential fuel injection systems? . They have one injector per cylinder b. Injectors are located in the intake manifold ports c. All injectors receive the same PCM commands simultaneously d. None of the answers is correct
All injectors receive the same PCM commands simultaneously
A restricted catalytic converter may cause ______. a. loss of power at high speeds b. stalling after starting c. a drop in engine vacuum as engine rpm increases d. All the answers are correct.
All the answers are correct.
Which sensor synchronizes the firing of the injectors and determines when piston number 1 is on the compression stroke?
CMP (camshaft position sensor)
Which of the following CANNOT be used as a source for the production of hydrogen?
Carbon dioxide
Which statement concerning E85 automotive fuel is false?
E85 is more fuel efficient than gasoline.
Which of the statements about hydrogen is false? a. A hydrogen atom is one proton and two electrons. b. Hydrogen contains more energy per weight than any other fuel. c. Fossil fuels are a combination of carbon and hydrogen. d. Hydrogen is produced in a fuel cell by breaking down water .
Hydrogen is produced in a fuel cell by breaking down water
Which of the following statements about hydrogen is not true? a. Hydrogen displaces air, so any release in an enclosed space could cause asphyxiation. b. Hydrogen must be stored as a compressed gas. c. Hydrogen is nontoxic. d. Hydrogen is highly flammable and there is risk for an explosion.
Hydrogen must be stored as a compressed gas.
Which of the following is the least likely to decrease fuel consumption of a hybrid vehicle? a. Low-rolling resistance tires b. Increased aerodynamic drag c. Stop-start systems d. Lighter and less powerful engines
Increased aerodynamic drag
A typical four-gas exhaust analyzer does not measure ____ emissions.
NOX
Which of the following gases is NOT considered to be harmful?
O2
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
Technician A says a mild hybrid has stop-start, regenerative braking, and electric motor assist available when the engine needs added power to overcome the load. Technician B says a full hybrid has stop-start, regenerative braking, electric motor assist, and can be driven by only electricity. Who is correct?
a only
Technician A says engine vacuum is normally measured in inches of mercury (in. Hg). Technician B says a pressure gauge that is labeled psig will read 14.7 psi at sea level. Who is correct?
a only
Technician A says proper tuning of the exhaust manifold tubes can create a partial vacuum that helps draw exhaust gases out of the cylinder, improving volumetric efficiency. Technician B says combined headers allow the cylinders next to each other in the firing order to be combined. This increases exhaust efficiency. Who is correct?
a only
Technician A says that gasoline can be used as a source of hydrogen for a fuel cell. Technician B says that carbon dioxide can be used as a source of hydrogen for a fuel cell. Who is correct?
a only
Technician A says the main advantage of a turbocharger is that it allows for an increase of power without a substantial decrease in fuel economy. Technician B says the use of exhaust gas to drive the turbocharger robs power from the engine when the vehicle is driven at low speeds. Who is correct?
a only
A CPI (central multiport injection) fuel injection system for a six-cylinder engine has ______. a. only one injector solenoid b. six poppet nozzles c. a single fuel pressure regulator d. All the answers are correct.
all answers are correct
The fuel pressure regulator can be located _____. a. on the throttle body b. on the fuel rail c. inside the fuel tank d. All the answers are correct.
all answers are correct
Which of the following conditions may result from too little EGR flow? a. The engine may overheat b. The engine may detonate c. The engine may emit an excessive amount of NOX d. All the answers are correct.
all answers are correct
Which of the following should be checked before proceeding with specific fuel injection and electronic control testing? a. vacuum lines b. PCV system c. engine coolant level d. All the answers are correct.
all answers are correct
Which of the following is NOT a metal used for producing exhaust manifolds? a. cast iron b. aluminum c. heavy-gauge sheet metal d. stainless steel
aluminum
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 as efficient as higher compression ratio engines c. It makes changes many times faster than older (mechanical) systems d. It has a feedback mechanism which allows it to constantly compensate for changing conditions
b
Which of the following tools cannot be used to test an oxygen sensor? a. digital voltmeter (DMM) b. analog voltmeter c. lab scope d. scan tool
b
Carbon monoxide is being discussed. Technician A says as the air/fuel ratio becomes richer, the CO levels decrease. Technician B says CO is a colorless, odorless, and highly poisonous gas that can cause death. Who is correct?
b only
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?
b only
Technician A says a pressure relief valve closes if the fuel supply line is restricted and pump pressure becomes very high. Technician B says the check valve in the pump prevents fuel from draining out of the fuel system and back into the fuel tank. This helps holds residual pressure in the fuel lines after the pump is turned off. Who is correct?
b only
Technician A says the emission vacuum schematic for the vehicle can only be found in the factory service manual. Technician B says an emissions vacuum schematic is given on a decal under the hood. Who is correct?
b only
Technician A uses a low-impedance test light to check for an injector pulse. Technician B uses a noid light to check the injector pulse. Who is correct?
b only
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
b only
Fuel injector firing is being discussed. Technician A says SFI systems control each injector separately so that it fires just before the intake valve opens. Technician B says sequential injector firing is more accurate than multiport systems. Who is correct?
both
Ignition coils are being discussed. Technician A says the primary coil is normally composed of 100 to 200 turns of 20-gauge wire. Technician B says the secondary coil consists of 15,000 to 25,000, or more, turns of very fine copper wire. Who is correct?
both
Technician A says a throttle body may house one fuel injector. Technician B says a throttle body may house two fuel injectors. Who is correct?
both
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
A/F ratio sensors are being discussed.Technician A says the output voltage of these sensors is much higher than a conventional O2S (oxygen sensor). Technician B say when the output of an A/F ratio sensor is looked at with an OBD-II generic scan tool, the voltage range will appear the same as a conventional O2S sensor, 0 to 1 volt. Who is correct?
both a and b
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?
both a and b
OBD II technology is being discussed. Technician A says the OBD II system has the ability to store a freeze frame (snapshot) of the operating conditions that existed when the fault occurred. Technician B says vehicle identification must be transmitted automatically to the scan tool. Who is correct?
both a and b
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?
both a and b
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?
both a and b
Technician A says a defective injector may cause cylinder misfiring at idle speed. Technician B says restricted injector tips may result in acceleration stumbles. Who is correct?
both a and b
Technician A says a loose ignition module mount can cause intermittent misfires or no-start conditions. Technician B says when installing a new ignition module, a small amount of heat conductive grease should be applied to the mounting surfaces. Who is correct?
both a and b
Technician A says diesel engines can be used in a hybrid powertrain. Technician B says a gasoline engine is normally used in hybrid powertrain. Who is correct?
both a and b
Technician A says high engine temperatures reduce HC and CO emissions. Technician B says incorrect ignition timing can increase the production of NOX.Who is correct?
both a and b
Technician A says the action of the wastegate is controlled directly by manifold pressure. Technician B says the wastegate is controlled by the PCM. Who is correct?
both a and b
Technician A says the biggest disadvantage of using CNG as a fuel is that the large amount space occupied by fuel cylinders limits the driving range of the vehicle. Technician B says bi-fuel vehicles are equipped to store both CNG and gasoline and will run on either.Who is correct?
both a and b
Technician A says there is less heat energy in high-octane gasoline and, therefore, less power is generated during combustion. Technician B says using a higher-octane gasoline than required will not produce more power unless the engine has a knock sensor that allows the system to adjust ignition timing to take advantage of the higher octane. Who is correct?
both a and b
Technician A says there is maximum EGR flow only when the vehicle is at a cruising speed with a very light load. Technician B says instead of an EGR valve many late-model engines use variable valve timing (VVT) to trap some exhaust gases in the combustion chamber. Who is correct?
both a and b
Technician A says turbocharging uses the heat energy in the engine's exhaust gases to drive a pump that compresses the intake air. Technician B says supercharging relies on the rotation of the engine to compress the air.
both a and b
The magnetic field surrounding the coil in a magnetic pulse generator moves when the ___. a. Reluctor tooth approaches the coil b. Reluctor tooth begins to move away from the pickup coil pole c. Reluctor is aligned with the pickup coil pole d. Both A and B
both a and b
When emptying a fuel tank, Technician A drains the fuel into plastic antifreeze containers then caps them tightly to prevent leaks. Technician B drains the fuel into approved gasoline storage containers. Who is correct?
both a and b
If the throttle is held wide open while the engine is cranked over by the starter motor, the fuel management system will enter _____ mode.
clear flood
The longest injector pulse width occurs during ______.
cold starting
What is an advantage of EI ignition? a. There are no moving parts, and therefore it requires little maintenance b. It is possible to control the ignition of individual cylinders to meet specific needs c. Mechanical timing adjustments are eliminated d. All the answers are correct.
d
Which of the following problems would NOT cause a oxygen sensor to appear bad? a. leaking fuel injector b. leaking intake manifold gasket c. leaking EGR valve d. leaking muffler to tailpipe gasket
d
Richer air-fuel mixtures ___.
decrease the electrical resistance inside the cylinder and decrease the required firing voltage
An EGR valve that does not fully close can cause all of the following except ___.
detonation
The first decision the computer makes in determining the best operating strategy is to determine the _____.
engine operating mode
A gasoline engine provides more torque at lower speeds than an electric motor.
false
All hybrids that have an electric motor inside the transmission have at least two.
false
All wastegates are controlled by the PCM.
false
HEV air-conditioning systems are identical to those used in a conventional vehicle.
false
On European vehicles equipped with twinchargers, the turbocharger boosts power at low speeds and the supercharger boosts power at high speeds.
false
Oxygen sensor condition can be checked using an ohmmeter.
false
The MAP sensor used on a turbocharged engine is calibrated the same as a MAP sensor for a nonturbocharged engine.
false
The spark plug wire is eliminated in all coil-per-cylinder ignition systems to reduce maintenance and the chances of EMI and RFI.
false
Which of the following would NOT cause the fuel trim to be out of range?
faulty IAC motor (idle air control)
What is the basic fuel for a fuel cell?
hydrogen
Leaner air/fuel mixtures ______.
increase the electrical resistance inside the cylinder and increase the required firing voltage
Where is the fuel pressure regulator on a returnless fuel system?
inside the fuel tank
The customer complains of a loss of power at highway speeds and a rough running engine at all speeds. A five-gas analyzer reveals these measurements at 2,500 rpm: HC = 700 ppm, CO = 0.2%, CO2 = 9.2%, O2 = 6.2%, and NOX = 330 ppm. What is the most likely cause?
lean misfire
Which of the following is NOT a component of the Toyota hybrid transaxle? a. motor/generators 1 and 2 b. multiple disc clutch c. planetary gear set d. differential assembly
multiple disc clutch
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?
neither
Technician A says large, low-speed industrial diesels require a high-quality and highly volatile fuel because they cannot tolerate excessive carbon deposits that result from low-volatile fuels. Technician B says the small, high-speed diesel engines found in passenger cars are relatively unaffected by carbon deposits and can run on low-quality fuel. Who is correct?
neither a nor b
Which of the following sensors is NOT used by the computerized ignition system to control ignition timing?
oxygen sensor
The function of the catalytic converter on a diesel engine is to eliminate ______.
particulates (black smoke)
If a fuel system loses pressure immediately after the ignition is turned off, the possible problems are all of the following except ___.
restricted fuel lines
While checking a pickup coil with an ohmmeter, a lower-than-normal reading indicates that the pickup unit is ___.
shorted
Reach, heat range, and air gap are all characteristics that affect the performance of which ignition system component?
spark plugs
A fuel injection system that uses a MAP sensor [manifold absolute pressure] to determine the amount of air entering the engine is called a _____-type injection system.
speed density
IAC (idle air control) valves are operated by a ______.
stepper motor
A twin scroll turbocharger uses two turbine wheels connected to a common shaft to improve performance and reduce lag.
true
Acoustic supercharging uses the pressure of the air bouncing back and forth between the closed intake valve and incoming air from the plenum to increase the amount of air drawn into the cylinders.
true
An ignition module may be damaged due to a poor electrical ground circuit.
true
Detonation can cause physical damage to the pistons, valves, bearings, and spark plugs.
true
For most actuators, the circuit driver in the PCM applies a ground to the circuit to turn the actuator on and removes the ground to turn the actuator off.
true
Fuel injectors are electromechanical devices.
true
Higher compression ratios tend to speed up combustion.
true
In some hybrids, regeneration begins as soon as the driver's foot leaves the accelerator.
true
Insufficient timing advance or retarded timing at higher engine speeds could cause hesitation and poor fuel economy.
true
Mode 6 data show the results of the monitor diagnostic tests.
true
OBD-II systems monitor the EVAP system for leaks.
true
On some new engine designs, the exhaust manifold is incorporated into the cylinder head to increase the efficiency of the driving the turbine.
true
Piezoelectric materials can emit a small amount of voltage when they are struck, squeezed, or exposed to vibration.
true
Some vehicles have two fuel pumps: an in-tank pump and a second pump mounted under the vehicle.
true
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.
true
The higher the altitude, the lower the atmospheric pressure.
true
The most widely used gasoline oxygenate additive is ethanol (ethyl alcohol).
true
Which of the following statements about P-series fuel is NOT true? a. It is a blend of natural gas liquids, ethanol, and biomass-derived cosolvents b. It is rated at 89 to 93 octane c. Unlike ethanol and methanol, it cannot be mixed with gasoline d. It produces less CO, HC, and CO2
Unlike ethanol and methanol, it cannot be mixed with gasoline
