Engine Performance Final
The maximum amount of voltage drop across any one wire or connector is: a. 1 volt b. .01 volt c. .1 volt d. 10 volts
.1 volt
At 2,000 rpm, the maximum allowable exhaust back pressure is approximately: a. 5 psi. b. 7.5 psi. c. 2.5 psi. d. 1.2 psi.
1.2 psi.
Which of the following represents 0.118A? a. 118 mA b. 1.18 kA c. 118 uA d. 1.18 mA
118 mA
50 pounds applied to a wrench 36 inches long will produce how much torque: a. 1000 ft lbs b. 150 ft lbs c. 1500 ft lbs d. 500 ft lbs
150 ft lbs
A low voltage signal from the O2 sensor indicates: a. A rich air/fuel mixture b. A lean air/fuel ratio c. A stoicheometric air/fuel ratio d. None of the above
A lean air/fuel ratio
Black smoke from the exhaust is caused by: a. Coolant entering the combustion chamber b. A lean air/fuel ratio c. Oil entering the combustion chamber d. A rich air/fuel ratio
A rich air/fuel ratio
All are advantages of DFI systems except: a. Increased fuel economy b. Additional NOx emissions c. Reduced carbon buildup d. Inhanced intake manifold tuning
Additional NOx emissions
A defective PCV valve can cause: a. Increased HC emissions b. Oil sludge c. Oil leaks d. All of the above
All of the above
A defective engine coolant temperature may cause: a. Hard engine starting. b. A lean air/fuel ratio. c. A rich air/fuel ratio. d. All of the above
All of the above
A turbocharger may be damaged by: a. Lack of oil b. Contaminants in the oil c. Ingestion of foreign material through the air intake d. All of the above
All of the above
Barometric pressure of 14.7 psi is equivalent to: a. 1 bar b. 1 atmosphere c. 100 kpa d. All of the above
All of the above
Magnetic pulse generators can be checked by which of the following: a. Resistance test b. AC voltage test c. Waveform signature test d. All of the above
All of the above
The computer may use the manifold absolute pressure sensor to: a. Monitor atmospheric pressure. b. Monitor the amount of pressure in the intake manifold. c. Monitor EGR operation d. All of the above
All of the above
High fuel pressure may be caused by: a. A defective fuel pressure regulator b. A fuel return line that is restricted c. A faulty fuel pump d. Both A and B
Both A and B
Technician A says a variable resistor can vary according to conditions such as temperature. Technician B says a variable resistor can vary according to conditions such as light. Who is correct? a. Technician A b. Technician B c. Both A and B d. Neither A nor B
Both A and B
Technician A says acceleration stumbles may be the result of restricted injector tips. Technician B says cylinder misfiring at idle speed may be caused by a defective injector. Who is correct? a. Technician A b. Technician B c. Both A and B d. Neither A nor B
Both A and B
Technician A says an engine with an intake manifold vacuum leak may misfire at idle and lower engine speeds. Technician B says a faster-than-normal idle speed in a fuel-injected engine may be caused by an intake manifold vacuum leak. Who is correct? a. Technician A b. Technician B c. Both A and B d. Neither A nor B
Both A and B
Technician A says any induction air leak after the MAF sensor can cause a poor running condition. Technician B says an air leak after the MAF sensor results in un-metered air. Who is correct? a. Technician A b. Technician B c. Both A and B d. Neither A or B
Both A and B
Technician A says current flows through the battery and electrical accessories on the vehicle from the alternator battery terminal. Technician B says AC voltage in the stator windings is induced by the rotor magnetic field. Who is correct? a. Technician A b. Technician B c. Both A and B d. Neither A nor B
Both A and B
Technician A says fuel that has low volatility can cause a buildup of deposits in the combustion chamber. Technician B says liquid gasoline will not burn. Who is correct? a. Technician A b. Technician B c. Both A and B d. Neither A nor B
Both A and B
Technician A says if a timing belt or chain becomes excessively worn, it is possible that a change in valve timing accuracy will result. Technician B says an excessively worn timing chain or belt can cause the timing to jump. Who is correct? a. Technician A b. Technician B c. Both A and B d. Neither A nor B
Both A and B
Technician A says if the IAC value is at or near zero on a speed density system there may be a manifold vacuum leak. Technician B says if the IAC value is to high there may be a build-up of carbon on the backside of the throttle plate. Who is correct? a. Technician A b. Technician B c. Both A and B d. Neither A nor B
Both A and B
Technician A says low fuel pressure may be caused by a restricted fuel filter. Technician B says when testing fuel pressure make sure the specifications are either for the engine running or the engine off. Who is correct? a. Technician A b. Technician B c. Both A and B d. Neither A nor B
Both A and B
Technician A says that compression can be raised by physically modifying the engine. Technician B says that compression can be effectively raised by using a turbocharger to force air into the engine. Who is correct? a. Technician A b. Technician B c. Both A and B d. Neither A nor B
Both A and B
Technician A says that if the engine rpm is constant, the scan tool should show a constant MAF grams-per-second reading. Technician B says the MAF sensor is a frequency producing sensor. Who is correct? a. Technician A b. Technician B c. Both A and B d. Neither A nor B
Both A and B
Technician A says the air intake temperature sensor (IAT) signal is very similar to the engine coolant temperature sensor signal. Technician B says cold intake air is denser than warm air. Who is correct? a. Technician A b. Technician B c. Both A and B d. Neither A nor B
Both A and B
Technician A says to relieve pressure on an EFI system, a pressure gauge may be connected to the fuel pressure test port and the bleed valve on the gauge opened with the bleed hose installed in an approved container. Technician B says before fuel system components on an EFI system can be removed, the fuel system pressure must be relieved. Who is correct? a. Technician A b. Technician B c. Both A and B d. Neither A nor B
Both A and B
Two technicians are discussing thermistors: Technician A says that thermistors change resistance as temperature changes. Technician B says thermistors are often used as computer input sensors. Who is correct? a. Technician A b. Technician B c. v d. Neither A nor B
Both A and B
Hybrid vehicles may be classified as: a. Mild b. Strong c. Parallel d. Both A and C
Both A and C
Oil is found in the air filter housing. What is the most likely cause? a. Worn piston rings b. Worn valve guide seals c. Clogged PCV valve d. Both A and C
Both A and C
While doing a battery capacity test rotate the load control until the ammeter reads: a. One half the batteries cold cranking rating b. Five times the batteries voltage rating c. Three times the ampere hour rating d. Both A and C
Both A and C
An O2 sensor may be used to: a. Monitor the air/fuel ratio. b. Monitor the temperature of the exhaust gas. c. Monitor the condition of the catalytic converter. d. Both A and C.
Both A and C.
Short-term fuel trim (STFT) adds or subtracts fuel to correct for: a. Permanent changes. b. Small or temporary changes. c. Changes in the O2 sensor signal. d. Both B and C
Both B and C
Converting mechanical energy into heat energy is accomplished by the: a. Suspension system b. Ignition system c. Brake system d. Cooling system
Brake system
Diesel fuel may be blended to improve: a. Emissions levels b. Cold starting c. Fuel economy d. Diesel fuel is not blended
Cold starting
A turbocharger: a. Compresses exhaust gases b. Increases fuel system pressure c. Compresses intake air d. None of the above
Compresses intake air
The voltage regulator controls generator output by: a. Limiting stator current b. Controlling rotor speed c. Controlling field current d. Switching off unneeded diodes
Controlling field current
An intercooler is used to: a. Increase the efficiency of the radiator. b. Prevent the turbocharger or supercharger from overheating. c. Cool the air from a supercharger or turbocharger before it reaches the combustion chamber. d. None of the above
Cool the air from a supercharger or turbocharger before it reaches the combustion chamber.
An Atkinson cycle engine uses variable valve timing to: a. Increase power and compression b. Decrease compression c. Compensate for high octane fuel d. All of the above
Decrease compression
An engine stalls during tight parking maneuvers. Which is the most likely cause? a. Defective power steering switch b. Defective mass air-flow sensor c. Defective MAP sensor d. Misadjusted throttle position sensor
Defective power steering switch
Octane is use to reduce: a. Detonation b. Volatility c. Carbon deposits d. Pre-ignition
Detonation
An automotive battery converts chemical energy into: a. Thermal energy b. Mechanical energy c. Electrical energy d. None of the above
Electrical energy
The starter motor converts: a. Electrical energy into thermal energy b. Mechanical energy into electrical energy c. Electrical energy into mechanical energy d. Chemical energy into mechanical energy
Electrical energy into mechanical energy
A bent fan blade should be straightened. True False
False
A thermistor changes resistance according to pressure. True False
False
A unit of measured electrical resistance is called an amp. True False
False
A weak valve spring will cause a steady low reading on a vacuum gauge. True False
False
Always reinstall the negative battery cable first when connecting the battery cables. True False
False
In order to save time it may be a good idea to guess at an adjustment True False
False
It takes two complete camshaft revolutions and one revolution of the crankshaft to complete one engine cycle, firing all cylinders once. True False
False
Oils with a higher viscosity rating should be used in colder temperatures. True False
False
Pressure and temperature are inversely proportional to each other. True False
False
The crankshaft, camshaft, and valves are located within the engine block. True False
False
The piston converts reciprocating motions into rotory motions. True False
False
Turbocharges and supercharges force more fuel into the cylinders to increase performance. True False
False
Oxides of nitrogen (NOx) are caused by: a. High cylinder temperature b. A rich air/fuel mixture c. Ignition misfires d. All of the above
High cylinder temperature
An IAC valve stuck in the closed position may cause all of the following except: a. Low idle speed. b. High idle speed. c. Stalling. d. Rough idle.
High idle speed.
The measurement of the rate at which work is performed is measured in: a. Momentum b. Torque c. Horsepower d. Energy
Horsepower
The evaporative system reduces: a. Hydrocarbons b. Carbon dioxide c. Oxides of nitrogen d. Carbon monoxide
Hydrocarbons
All are functions of the modern fuel system except: a. Atomize the fuel b. Store fuel until needed c. Mix the fuel with the air d. Filter the fuel entering the engine
Mix the fuel with the air
All of the following are responsible for air entering the combustion chamber except: a. Vacuum b. Momentum c. The venturi principle d. Atmospheric pressure
Momentum
Technician A says fuel injectors may be cleaned by soaking them in solvent. Technician B says it is a good idea to use a wire brush to unclog injectors. Who is correct? a. Technician A b. Technician B c. Both A and B d. Neither A nor B
Neither A nor B
Technician A says that air-fuel ratio (AF) sensors can be diagnosed with a voltmeter. Technician B says the AF sensor is a Hall effect sensor. Who is correct? a. Technician A b. Technician B c. Both A and B d. Neither A nor B
Neither A nor B
In any fuel injection system the fuel pressure must be high enough to: a. Open the injectors. b. Prevent the fuel from boiling. c. Knock the carbon off the back of the intake valves. d. All of the above.
Prevent the fuel from boiling.
During cold engine start or acceleration, the air-fuel mixture may be: a. Leaner than normal b. Richer than normal c. Remain 14.7:1 d. None of the above
Richer than normal
As a battery discharges: a. Sulfuric acid joins with lead b. Oxygen separates from hydrogen c. The electrolyte contains very little oxygen d. None of the above
Sulfuric acid joins with lead
A clutch pedal position sensor (CPP) sensor is being discussed: Technician A says that the CPP sensor tells the ECM if the clutch is engaged or disengaged. Technician B says a defective CPP sensor also affects MAF sensor calculations. Who is correct? a. Technician A b. Technician B c. Both A and B d. Neither A nor B
Technician A
Technician A says GDI systems operate under very high pressures. Technician B says GDI systems are no longer used in modern engines. a. Technician A b. Technician B c. Both A and B d. Neither A or B
Technician A
Technician A says a fuel level sensor malfuntion may cause a trouble code to set. Technician B says the evaporative emissions check test is only run when the fuel tank is empty. Who is correct? a. Technician A b. Technician B c. Both A and B d. Neither A nor B
Technician A
Technician A says a parallel hybrid vehicle uses both the electric motor and the gasoline engine to directly power the drive wheels. Technician B says that the series hybrid uses just the gasoline engine to power the drive wheels, and the battery is used to power accessories. Who is correct? a. Technician A b. Technician B c. Both A and B d. Neither A nor B
Technician A
Technician A says a rich air-fuel mixture may be the result of higher-than-normal fuel pressure. Technician B says higher-than-normal fuel pressure causes a lean air-fuel ratio. Who is correct? a. Technician A b. Technician B c. Both A and B d. Neither A nor B
Technician A
Technician A says higher fuel pressure at wide-open throttle is the result of low manifold vacuum to the pressure regulator in the SFI system. Technician B says higher fuel pressure at wide-open throttle is maintained by the PCM in the SFI system to enrichen the air/fuel ratio for better acceleration. Who is correct? a. Technician A b. Technician B c. Both A and B d. Neither A and B
Technician A
Technician A says never connect or disconnect the battery charger cables from the battery terminals with the charger in operation. Technician B says when disconnecting a battery the first disconnection should be the positive battery cable. Who is correct? a. Technician A b. Technician B c. Both A and B d. Neither A nor B
Technician A
Technician A says the exhaust gas from the cylinders of a turbocharged engine is directed past the turbine wheel. Technician B says the exhaust gas from the cylinders of a turbocharged engine is directed past the compressor wheel. Who is correct? a. Technician A b. Technician B c. Both A and B d. Neither A nor B
Technician A
Technician A says the poppet nozzles in the CMFI system are opened by fuel pressure. Technician B says the computer opens the poppet nozzles in the CMFI system. Who is correct? a. Technician A b. Technician B c. Both A and B d. Neither A nor B
Technician A
Technician A says to use only sockets that are designed for use on impact wrenches when using an impact wrench. Technician B says any socket is suitable to use with an impact wrench as long as the technician visually inspects the socket. Who is correct? a. Technician A b. Technician B c. Both A and B d. Neither A nor B
Technician A
Technician A says a diagnostic code (DTC) tells the technician exactly which part to replace. Technician B says that OBD II vehicles require the use of a scan tool to read diagnostic codes. Who is correct? a. Technician A b. Technician B c. Both A and B d. Neither A nor B
Technician B
Technician A says atmospheric pressure increases as altitude increases. Technician B says atmospheric pressure decreases as altitude increases. Who is correct? a. Technician A b. Technician B c. Both A and B d. Neither A nor B
Technician B
Technician A says oxides of nitrogen are changed to carbon dioxide and water by a three-way catalytic converter. Technician B says hydrocarbons and carbon monoxide are changed to carbon dioxide and water by a two-way catalyst. Who is correct? a. Technician A b. Technician B c. Both A and B d. Neither A nor B
Technician B
Technician A says reducing spark advance can cause spark knock. Technician B says excessive carbon deposits can cause spark knock. Who is correct? a. Technician A b. Technician B c. Both A and B d. Neitehr A or B
Technician B
Technician A says that the intake air temperature (IAT) sensor is a voltage-generating sensor. Technician B says the MAF sensor is a reference voltage sensor. Who is correct? a. Technician A b. Technician B c. Both A and B d. Neither A nor B
Technician B
Technician A says the DFI fuel injector runs at lower fuel pressures than port fuel injectors. Technician B says that the DFI fuel injector may be difficult to remove from the cylinder head. Who is correct? a. Technician A b. Technician B c. Both A and B d. Neither A nor B
Technician B
Technician A says the PCM supplies power and ground to magnetic pulse generators. Technician B says the PCM supplies power and ground to Hall-effect sensors. Who is correct? a. Technician A b. Technician B c. Both A and B d. Neither A nor B
Technician B
Technician A says the hot-wire MAF sensor sends a varing voltage signal back to the PCM.. Technician B says that contamination of the hot-wire MAF sensor can cause drivability problems. Who is correct? a. Technician A b. Technician B c. Both A and B d. Neitehr A nor B
Technician B
Injector pulse width is: a. The amount of time the injector is held open and injecting fuel. b. The diameter of the injector spray pattern. c. The percentage of time the injector is held open and injecting fuel. d. How far the PCM opens the injector.
The amount of time the injector is held open and injecting fuel.
Brake horsepower may be defined as a. The amount of horsepower required to overcome the internal friction of the engine b. The maximum amount of horsepower the engine can produce before it breaks c. The amount of horsepower required to stop a vehicle d. The useable power at the engine's crankshaft
The useable power at the engine's crankshaft
A defective radiator cap may cause the upper radiator hose to collapse when the coolant is cold. True False
True
A typical pressure gauge will read atmospheric pressure as zero. True False
True
If the exhaust is blue there is excessive amounts of oil entering the combustion chamber. True False
True
In a parallel circuit the total resistance is less than the value of any resistor in the circuit. True False
True
Internal combustion engines convert chemical energy into thermal energy and thermal energy into mechanical energy. True False
True
One complete combustion cycle requires two revolutions of the crankshaft. True False
True
Oxides of nitrogen (NOx) form only under high combustion temperatures. True False
True
The combustion chamber is the space between the top of the piston and the cylinder head. True False
True
Vacuum is described as a lack of pressure. True False
True
Which is not a component of the starting system? a. Starter solenoid b. Battery c. Voltage regulator d. Starter motor
Voltage Regulator
Glow plugs are used in diesel engines to: a. Warm the fuel b. Warm the combustion chamber c. Warm the intake air d. Ignite the fuel
Warm the combustion chamber
A thermistor is a solid-state variable resistor made from a semiconductor material that changes resistance in relation to: a. pressure changes. b. voltage changes. c. volume changes. d. temperature changes.
temperature changes.
The acceptable amount of alcohol mixed with gasoline is: a. up to 10 percent. b. more than 10 percent. c. up to 20 percent. d. less than 1 percent.
up to 10 percent.
All of the following are types of mass air flow sensors except: a. variable reluctance-type sensors b. heated resistor-type sensors c. hot wire-type sensors d. heated grid-type sensors
variable reluctance-type sensors
