AUTT 1040 Final
Which of the following statements is true of biodiesel as an automotive fuel?
Biodiesel can act as a lubricant in automotive fuel systems.
Which of the following statements is true of biodiesel?
Biodiesel is safe, biodegradable, and reduces serious air pollutants.
Two technicians are discussing the characteristics of a low-pressure supply pump. Technician A says that the fuel pump in the fuel tank supplies fuel to the high-pressure fuel pump at a pressure of approximately 60 PSI. Technician B says that the fuel filter is located in the fuel tank and is part of the fuel pump assembly. Which of the following statements about the scenario is true?
Both technician A and B's assessments are accurate.
Two technicians were discussing the characteristics of an accelerator pedal position sensor. Technician A said that the accelerator pedal position sensor uses two and sometimes three separate sensors, which act together to give accurate accelerator pedal position information to the controller. Technician B said that the accelerator pedal position sensor uses two and sometimes three separate sensors to check that the sensor is working properly. Which of the following about the scenario is true?
Both technician A's and technician B's assessments are accurate.
A high current is passed through the sensing wire for a short time, but long enough to cause the wire to glow due to the heat.
Both technician A's and B's assessments are accurate.
Technicians are discussing engine start systems. Technician A says that the normal stopping position of an engine when it stops is 70 degrees before top dead center, plus or minus 20 degrees. Technician B says that the PCM can determine the cylinder position, using the crankshaft and camshaft position sensors. Which of the following statements about this scenario is true?
Both technician A's and B's assessments are accurate.
Technicians were discussing gasoline direct-injection service. Technician A says that gasoline direct injection (GDI) systems operate at high pressure. Technician B says that injectors can often be heard with the engine running and the hood open. Which of the following statement about this scenario is true?
Both technician A's and B's assessments are accurate.
Two technicians are discussing the location of fuel filters. Technician A says that fuel filters can be located on the fender panel in the engine panel. Technician B says that fuel filters can be installed under the vehicle near the fuel tank. Which of the following is true in this scenario?
Both technician A's and B's assessments are accurate.
Two technicians are discussing the throttle position sensor computer input functions. Technician A says that the computer senses any change in throttle position and changes the fuel mixture and ignition timing. Technician B says that the actual change in fuel mixture and ignition timing is also partly determined by the other sensors, such as the manifold pressure sensor and the oxygen sensor. Which of the following is true in this scenario?
Both technician A's and B's assessments are accurate.
Two technicians had different views on computer output devices. Technician A stated that the computer can vary the amount of time the injectors are held open. Technician B stated that the computer can control the flow of gasoline fumes from the charcoal canister to the engine. Which of the following statements about this scenario is true?
Both technician A's and B's assessments are accurate.
Two technicians had different views on temperature sensors. Technician A stated that a throttle-body temperature sensor is used to sense the temperature of the air entering the engine. Technician B argued that an intake air temperature sensor is used to sense the temperature of the air entering the engine. Which of the following statements about this scenario is true?
Both technician A's and B's assessments are accurate.
Two technicians were discussing a waste-spark ignition system. Technician A stated that each coil in a waste-spark ignition system is a true transformer, in which the primary winding and secondary winding are not electrically connected. Technician B stated that the coil polarity is determined by the direction the coil is wound and cannot be changed. Which of the following statements about this scenario is true?
Both technician A's and B's assessments are accurate.
Two technicians were discussing the characteristics of the magnetic crankshaft position sensor. Technician A stated that a magnetic crankshaft position sensor uses the changing strength of the magnetic field surrounding a coil of wire to signal the module and computer. Technician B stated that a magnetic crankshaft position sensor uses light from an LED and a phototransistor to signal the computer. Which of the following statements about this scenario is true?
Both technician A's and B's assessments are accurate.
Two technicians were discussing the parts of a computer. Technician A stated that the microprocessor is considered the brain of a computer. Technician B stated that some computers use more than one microprocessor, called a coprocessor. Which of the following statements about this scenario is true?
Both technician A's and B's assessments are accurate.
Two technicians were discussing the safety procedures when working with alternative fuels. Technician A stated that long-sleeved shirt and pants need to be worn to help protect bare skin from the freezing effects of gases under pressure. Technician B stated that if any fuel gets on the skin, the area should be washed immediately. Which of the following statements about this scenario is true?
Both technician A's and B's assessments are accurate.
Two technicians were discussing the strategies of the automatic transmission fluid. Technician A stated that if the temperature of the automatic transmission fluid is low, overdrive gear is disabled. Technician B stated that if the temperature of the automatic transmission fluid is high, the torque converter clutch is applied to help reduce the temperature of the fluid. Which of the following statements about this scenario is true?
Both technician A's and B's assessments are accurate.
Two technicians were discussing the use of the fuel compensation sensor in E85 vehicles. Technician A stated that the fuel compensation sensor is used to measure the percentage of ethanol blend in the fuel. Technician B stated that the fuel compensation sensor is used to measure the temperature of the fuel. Which of the following statements about this scenario is true?
Both technician A's and B's assessments are accurate.
Two workshop trainees are discussing barometric absolute pressure (BARO) sensor while working. Trainee A says the sensor detects altitude at key on and engine off. Trainee B says it detects altitude while running the vehicle at wide-open throttle. Which of the following statements is true about this scenario?
Both trainees are correct.
Trainees are learning to test a manifold absolute pressure (MAP) sensor with a scope. Trainee A says the output should be a variation in voltage. Trainee B says the output should be a variation in frequency. In this scenario, which of the following statements is true?
Both trainees' statements are correct.
Which of the following is true of the engine coolant temperature (ECT) sensor construction?
Coolant sensors have very high resistance when the coolant is cold and low resistance when the coolant is hot.
Which of the following is true of downstream regulation in fuel-pressure regulators?
Downstream regulation minimizes fuel-pressure pulsations caused by pressure drop across the injectors as the nozzles open.
Diagnostic trouble code P0133 most likely results from ________.
EGR or fuel-system fault
Which of the following is a true statement about fuel tanks?
Fuel tanks are usually mounted just ahead of or behind the rear axle.
Which of the following statements is true of Hall effect?
Hall effect is the ability to generate a voltage signal in semiconductor material by passing current through it in one direction and applying a magnetic field to it at a right angle to its surface.
Which of the following statements is true of the characteristics of incoming air?
Hot air is less dense and contains less oxygen than cold air.
Which of the following is true of refining?
Hydrocracking is similar to catalytic cracking in that it uses a catalyst, but the catalyst is in a hydrogen atmosphere.
Which of the following statements is true of spark plugs?
If one or a few spark plugs are black, those cylinders should be checked for proper firing.
Which of the following statements is true of ignition timing?
If the engine is equipped with a distributor, it may or may not be possible to adjust the base or the initial timing.
Which of the following is true of port-fuel-injected engines?
If the pressure regulator cannot hold a vacuum it should be replaced.
Which of the following is true of the powertrain control module (PCM) for the throttle position (TP) sensor?
In automatic transmission shift points, if the throttle is barely open, the shift point occurs at the minimum speed designed for the vehicle.
Which of the following is the result of the potentiometer moving along with the vane?
It causes a change in the signal voltage supplied to the computer.
Which of the following is true of the central port injection (CPI) used in automobiles?
It combines the single injector of a TBI system with the equalized fuel distribution of a PFI system.
With reference to oxygenated gasoline fuels, which of the following is true of methyl tertiary butyl ether?
It is not as sensitive to water as are other alcohols.
Which of the following is true of a single cell wide-band oxygen sensor?
It looks similar to a conventional four-wire zirconia oxygen sensor.
When a wide-band oxygen sensor was scanned, H02S1 indicated a positive current. What does this mean?
It means that the PCM is pumping current in the diffusion gap due to a rich exhaust.
What does the baud rate in a computer represent?
It represents the speed of the computer.
Two technicians were discussing the types of output drivers. Technician A stated that high-side drivers are transistors inside the computer that complete the ground path of relay coil. Technician B stated that low-side drivers control the power side of the circuit. Which of the following statements about this scenario is true?
Neither technician A's nor B's assessment is accurate.
Which of the following statements is true of the storage function of computers?
Nonvolatile random-access memory (RAM) memory is used for the storage of odometer information in an electronic speedometer.
Which of the following is true of a potentiometer?
One terminal is a ground wire back to the computer.
Technicians are checking a throttle position (TP) sensor using a scan tool. Having performed all preliminary tests with correct results, the technicians next use a small wedge to increase the throttle opening, note the throttle percentage reading to be 12%, reset the ignition, and note the reading in the scan tool. They find the scan tool shows the amount of throttle opening as 0%. Technician A considers the TP sensor as normal. Technician B considers the TP sensor as faulty. Which of the following is true in this scenario?
Only technician A's assessment is accurate.
Two technicians are discussing Lexus port-and direct-injection systems. Technician A says that the Lexus D-4S system combines direct-injection injectors with port fuel-injectors. Technician B says that the direct-injection injectors are located near the intake valve and the port fuel-injectors are located in the combustion chamber. Which of the following statements about this scenario is true?
Only technician A's assessment is accurate.
Two technicians are discussing mass airflow (MAF) sensor output test. Technician A says that the normal airflow is 3 to 7 grams per second. Technician B says that a small hole in the inlet hose would represent a very small percentage of false air at idle. Which of the following statements is true about this scenario?
Only technician A's assessment is accurate.
Two technicians are discussing the level of oxygen in the exhaust. Technician A says that if the exhaust contains less oxygen, the computer reduces fuel delivery. Technician B says that if the exhaust contains more oxygen, the computer assumes that the intake charge is rich. Which of the following is true in this scenario?
Only technician A's assessment is accurate.
Two technicians are discussing the method of performing a tap test of a mass airflow (MAF) sensor in a vehicle. Technician A suggests that with the engine running at idle speed, gently tap the MAF sensor with the fingers of an open hand. Technician B suggests that if the engine stumbles or stalls, the MAF sensor is not defective. Which of the following statements is true in this scenario?
Only technician A's assessment is accurate.
Two technicians are discussing the use of a scan tool to test the throttle position sensor of a vehicle. Technician A suggests that a throttle position sensor can be tested using a digital voltmeter with three test leads connected in series between the sensor and the wiring harness connector. Technician B suggests that a throttle position sensor can be tested using a breakout box that is connected in parallel between the computer and the wiring harness connector(s). Which of the following is true in this scenario?
Only technician A's assessment is accurate.
Two technicians were discussing the characteristics of ethanol-fueled vehicles. Technician A stated that ethanol-fueled vehicles generally produce the same pollutants as gasoline vehicles. Technician B stated that ethanol-fueled vehicles produce more carbon monoxide and carbon dioxide emissions than gasoline vehicles. Which of the following statements about this scenario is true?
Only technician A's assessment is accurate.
Two technicians were discussing the ignition system of a vehicle. Technician A stated that all ignition systems use electromagnetic induction to produce a high-voltage spark from the ignition coil. Technician B stated that electromagnetic induction means that a current can be created in a conductor by a static magnetic field. Which of the following statements about this scenario is true?
Only technician A's assessment is accurate.
Two technicians were discussing the production of cellulose ethanol. Technician A stated that cellulose ethanol can be produced from agricultural plant wastes. Technician B stated that cellulosic biomass does not contain lignin. Which of the following statements about this scenario is true?
Only technician A's assessment is accurate.
Two technicians were discussing the ways to control the amount of vacuum flowing through a vacuum solenoid. Technician A stated that a pulse width modulation could be used. Technician B stated that a switched driver could be used. Which of the following statements about this scenario is true?
Only technician A's assessment is accurate.
Workshop service personnel hear a customer's complaint about her car. Suspecting a fault in the ETC system, they connect a factory scan tool to the vehicle and check for Diagnostic Trouble Codes (DTCs). The technicians find no DTCs stored in the PCM. Technician A checks scan tool data for possible fault areas in the system. Technician B believes the absence of DTCs indicates the system is fine and there is no need for further checks. Which of the following statements is accurate in this scenario?
Only technician A's assessment is accurate.
Technicians A and B are discussing the changes made to the current year's model of the Goliath pick-up truck. As they look at the spec-sheet, they come across the electronic throttle control (ETC) system introduced in the model. Technician A says the fuel economy of the vehicle would probably have improved because of this. Technician B says the ETC system has nothing to do with fuel economy. In this scenario, which of the following statements is true?
Only technician A's statement is accurate.
A customer at a workshop complains of engine knocking in his vehicle since his last fill up. He mentions that the manufacturer suggested regular grade gasoline and he is not sure about the grade he used. Technician A suggests the customer use fuel with a pump octane rating of 89. Technician B advises on using gasoline rated at 87 on the AKI. Which of the following statements about this scenario is true?
Only technician B's assessment is accurate.
Technicians suspect a flooded engine in a car that refuses to start. They find the throttle position (TP) sensor output to be 0.5 V when the engine is off and the ignition is on. They find the throttle opening percentage on the scan tool increases and decreases with corresponding increase and decrease of the throttle. They next attempt keeping the throttle fully depressed while cranking the engine. When the engine still does not start, technician A suggests the TP sensor is defective, while technician B suggests the engine is not flooded in the first place. Which of the following is true in this scenario?
Only technician B's assessment is accurate.
Two technicians are discussing how to siphon gasoline from a tank. Technician A suggests that a siphon be attached through the filler neck. Technician B suggests that the check-ball should be disconnected first and then a siphon can be attached. Which of the following is true in this scenario?
Only technician B's assessment is accurate.
Two technicians are discussing the characteristics of port-fuel-injected engines. Technician A says that the pressure inside the intake manifold is high at idle. Technician B says that the pressure exerted on the diaphragm is reduced when manifold vacuum is applied above the diaphragm inside the fuel-pressure regulator. Which of the following about the scenario is true?
Only technician B's assessment is accurate.
Two technicians are discussing the effects of partial clogging of the fuel filter. Technician A says that there will be high power at higher engine speeds. Technician B says that the engine will cut out on acceleration during heavy-load acceleration. Which of the following is true in this scenario?
Only technician B's assessment is accurate.
Two technicians were discussing the characteristics of noid lights. Technician A says that the noid light flashes if the injector circuit is not working correctly. Technician B says that if the noid light is on, both a power and a ground are present. Which of the following about the scenario is true?
Only technician B's assessment is accurate.
Two workshop trainees are learning to check for spark. They are given an engine whose ignition system has a separate ignition coil. Trainee A says the spark plug wire needs to be removed from the spark plug and then tested with a spark tester. Trainee B says the ignition coil wire should be removed from the distributor cap and then be tested with a spark tester. Which of the following statements about this scenario is true?
Only trainee B's statement is accurate.
Which of the following statements is true of propane?
Propane is a by-product of petroleum refining of natural gas.
Which of the following is true of the operation of oxygen sensors?
Rich exhaust gases contain little oxygen as compared to exhaust from a lean mixture.
Manufacturers have placed the pressure regulator by the tank instead of under the hood on mechanical returnless systems to avoid which of the following problems?
Rising in-tank temperatures and increases in fuel vaporization and volatile organic compound (VOC) emissions.
Three technicians training to inspect ignition coils have a discussion on how to diagnose coil health. Technician A says a coil is bad if the primary winding shows resistance in kilohms. Technician B says the primary winding resistance should always show resistance in kilohms. Technician C says coil health is not determined by its resistance. Which technician is right in his assessment?
Technician A
Which of the following is not true of electronic throttle control (ETC) systems?
The ETC system reduces the number of mechanical moving parts in a vehicle.
Which of the following statements is true of the construction of an ignition coil in a vehicle?
The center of an ignition coil contains a core of laminated soft iron.
Which of the following is a true statement about the positive displacement pump?
The chambers are formed by rollers or gears in a rotor plate.
In the context of the different modes of operation of gasoline direct-injection systems, which of the following is true of the first injection in the stratified catalyst heating mode?
The first injection is on the compression stroke just before combustion.
Which of the following is true of port fuel-injection systems used in vehicles?
The fuel is injected almost directly into the combustion chamber.
Which of the following is true of the functioning of a hot film sensor?
The hot film sensor uses a thermistor to measure the temperature of the incoming air.
Which of the following is true of a vehicle driven by a turbocharged engine under partial-load condition?
The intake manifold pressure is greater than atmospheric pressure.
Which of the following is true of the sensor signal generated by the fuel rail pressure sensor?
The sensor signal provides an analog signal to the PCM that varies in voltage as fuel rail pressure changes.
Which of the following is true of the dynamic pressure test?
There should never be any fuel present on the vacuum side of the regulator diaphragm.
Which of the following is a true statement about throttle position sensors?
The three-wire potentiometer sensor produces an analog voltage signal that is proportional to the throttle plate position.
Which of the following statements is true of the cetane rating of E-diesel?
To increase the cetane number back to that of conventional diesel fuel, ditertbutyl peroxide is added to E-diesel.
Which of the following statements is true of engine coolant temperature sensors?
When the engine is cold, the fuel mixture must be richer to prevent stalling and engine stumble.
Which of the following is true of the operation of the engine in a port fuel-injection system?
When the engine starts, the engine speed is high to provide for proper operation when the engine is cold.
Which of the following is true of idle control (IAC) strategy?
When the throttle position (TP) sensor voltage is at idle, the powertrain control module (PCM) then controls idle speed using the idle air control (IAC) to maintain the commanded idle speed.
Technicians working on a single-cylinder motorcycle plug the ignition system into an oscilloscope. The technicians look at the readings, discuss among themselves, and arrive at the conclusion that the airdash-fuel mixture is too lean. Which of the following readings on the oscilloscope would prompt them to make this conclusion?
a large vertical line with a height of 21,000 volts
A Schmitt trigger is most likely used to?
convert the analog signal into a digital signal
When a barometric absolute pressure (BARO) sensor is out-of-range at ignition on, it is most likely due to ________.
damaged manifold absolute pressure (MAP) sensor O-ring
A customer takes his vehicle to a workshop for an exhaust emission test. The vehicle fails the test. Which of the following is the most likely cause if fuel is determined as the reason for failure?
gas tank being filled above its manufacturer-specified capacity
Which of the following modes of operation is used during high-speed and/or high-torque conditions?
homogeneous mode
Which of the following instruments is used to test diesel fuel?
hydrometer
The three-wire type of coil-on-plug ignition includes the following wires, except the ________.
neutral wire
Which of the following is the first step in cleaning the throttle body?
removing the air inlet hose from the throttle body with the ignition off
White chalky deposits on an oxygen sensor indicate that failure was most likely caused by ________.
silica deposits in the fuel
Which of the following chemicals in diesel fuel is most likely to damage engine components and cause piston ring wear?
sulfur
The following tasks are performed for the correct functioning of the engine coolant temperature sensor, except ________.
using an 80/20 mixture of antifreeze and water
Which of the following fuels produces virtually no particulate emissions?
Fischer-Tropsch fuel
Which of the following statements is true of Fischer-Tropsch fuels?
Fischer-Tropsch fuels can be blended with traditional transportation fuels with little equipment modification.
Which of the following is true of fuel-pressure regulators?
Fuel-pressure regulators on fuel-return-type fuel-injection systems are installed on the downstream side of the injectors at the end of the fuel rail.
Which of the following is a significant characteristic of a read-only memory (ROM)?
Read-only memory (ROM) retains data even when the power to the computer is shut off.
Which of the following driveability indices offers the best cold-weather driveability?
1000degrees° F
Which of the following readings from a manifold absolute pressure (MAP) sensor is most likely to indicate the vehicle is being run at altitudes above sea level?
3 V at key on, ignition off
Determine the American Petroleum Institute (API) gravity of diesel fuel, if the specific gravity of diesel fuel at 60°F is 0.87.
31.14
A man driving a sports car in the Appalachians arrives at a gas station on top of a hill. His altimeter shows the altitude as 2,300 feet above sea level. His vehicle is designed by the manufacturer to accept midgrade gasoline by AKI standards. If the following choices of octane rated gasoline are available to him, which octane rating would most likely be the best choice for his vehicle?
87
Which of the following differentiates a manifold absolute pressure (MAP) sensor from a barometric absolute pressure (BARO) sensor?
A MAP sensor is vented into the intake manifold, while a BARO sensor is vented to the atmosphere.
Which of the following is true of burn-off circuits used in mass airflow (MAF) sensors?
A high current is passed through the sensing wire for a short time, but long enough to cause the wire to glow due to the heat.
Which of the following statements is true of ignition scope testing?
A worn distributor cap can cause the firing lines to be higher than normal for all cylinders.
Which of the following is true of the functioning of an electronic returnless fuel system?
An electronic returnless fuel system is capable of continuously varying rail pressure as a result of engine vacuum, engine fuel demand, and fuel temperature.
Which of the following is true of the symptoms of a failed mass airflow (MAF) sensor in a vehicle?
At wide-open throttle (WOT), the grams per second, as read on a scan tool, should exceed 100.
