Gasoline Fuel Systems
Chapter 48
- 1.The most important job of the fuel system is to optimize engine performance while:
- A.
Keeping fuel consumption and emissions to a minimum.
- B.
Keeping car owners happy with acceptable vehicle performance.
- C.
Making sure all DMV rules are adhered to.
- D.
Making sure all DMV rules are adhered to.
- 2.Early mechanically operated fuel systems typically sprayed:
- A.
Fuel from an injector in the throttle body on the intake manifold.
- B.
A pulsed stream of fuel delivered behind the intake valves.
- C.
A sequential delivery of fuel from individual injectors on the intake manifold.
- D.
A continuous flow of fuel through injectors at each intake port.
- 3.All of these are advantages of electronically controlled fuel injection over mechanical injection systems EXCEPT:
- A.
Continuous air–fuel adjustments are possible.
- B.
Reduced emissions are achieved.
- C.
Fuel can be delivered in a continuous stream.
- D.
Reduced fuel consumption is achieved.
- 4.Tech A says that an electronic control unit (ECU)/power train control module (PCM) is needed to make electronic fuel injection (EFI) function correctly. Tech B says that most early EFI systems were throttle body injection (TBI) type systems. Who is correct?
- A.
Tech A
- B.
Tech B
- C.
Both Techs A and B
- D.
Neither Tech A nor B
- 5.All of these are subsystems of modern fuel injection systems EXCEPT:
- A.
A fuel supply system.
- B.
An emissions system.
- C.
An air supply system.
- D.
A fuel metering system.
- 6.Which of these fuel characteristics helps to prevent the air–fuel mixture from spontaneously igniting in the combustion chamber?
- A.
The ignition temperature
- B.
The octane rating
- C.
The cetane rating
- D.
The antiknock rating
- 7.For gasoline to burn properly, it must be mixed with the right amount of:
- A.
Carbon.
- B.
Air.
- C.
Hydrogen.
- D.
Lead.
- 8.Which of these describes when the air–fuel mixture spontaneously ignites before the spark plug fires?
- A.
Detonation
- B.
Advanced ignition
- C.
Spark advance
- D.
Pre-ignition
- 9.Tech A says that a slightly lean mixture offers good fuel economy and low exhaust emissions. Tech B says that a mixture that is too rich fouls spark plugs and causes incomplete burning. Who is correct?
- A.
Tech A
- B.
Tech B
- C.
Both Techs A and B
- D.
Neither Tech A nor B
- 10.For a gasoline engine, the optimum air to fuel ratio by mass is about:
- A.
12.1:1.
- B.
14.7:1.
- C.
16.3:1.
- D.
18.5:1.
- 11.The term “stoichiometric ratio” describes the chemically correct air–fuel ratio necessary to achieve all of these EXCEPT:
- A.
Complete combustion of the fuel and air.
- B.
Good fuel economy.
- C.
Maximum engine power.
- D.
Reasonably clean emissions.
- 12.Tech A says that most fuel-injected vehicles use one or two electrical pumps to supply the fuel system with pressurized fuel. Tech B says that with today's systems, a fuel pump is likely to be located inside the fuel tank. Who is correct?
- A.
Tech A
- B.
Tech B
- C.
Both Techs A and B
- D.
Neither Tech A nor B
- 13.A resistor that changes its resistance with changes of temperature is called a:
- A.
Thermistor.
- B.
Transistor.
- C.
Potentiometer.
- D.
Rheostat.
- 14.Modern fuel filters typically have all of these characteristics EXCEPT:
- A.
They use pleated paper as a filter element.
- B.
They prevent small amounts of water from getting past.
- C.
They serve as an accumulator to quiet the system.
- D.
They are directional in nature.
- 15.Which of these is a sensor for measuring crankshaft position?
- A.
Camshaft position sensor (CMP)
- B.
Crankshaft position sensor (CKP)
- C.
Intake air temperature (IAT)
- D.
Manifold absolute pressure sensor (MAP)
- 16.The purpose of the vehicle speed sensor (VSS) is to measure the:
- A.
Turbulence in the incoming airstream.
- B.
Throttle position.
- C.
Speed of the vehicle.
- D.
Coolant temperature.
- 17.The barometric pressure (BARO) sensor works in conjunction with the:
- A.
Mass airflow (MAF) sensor.
- B.
Manifold absolute pressure (MAP) sensor.
- C.
Vehicle speed sensor (VSS).
- D.
Intake air temperature (IAT) sensor.
- 18.Which of these has the function of monitoring the noise that is created by a pressure spike in the combustion chamber?
- A.
Barometric pressure (BARO) sensor
- B.
Manifold absolute pressure (MAP) sensor
- C.
Detonation sensor
- D.
Knock sensor
- 19.Tech A says that engine misfiring will cause a lean exhaust condition. Tech B says that engine misfiring can cause overheating of the catalytic converter. Who is correct?
- A.
Tech A
- B.
Tech B
- C.
Both Techs A and B
- D.
Neither Tech A nor B
- 20.The on and off time of a stepper motor relates to its duty cycle, which is generally expressed as a:
- A.
Percentage.
- B.
Numeric value.
- C.
Binary number.
- D.
Hexi-decimal value.
- 21.A variation in pulse width at a fixed frequency is called:
- A.
Duty cycle.
- B.
Analog cycle.
- C.
Pulse-width modulation.
- D.
Digital cycle.
- 22.Tech A says that fuel pump pressure can often be tested by accessing a test port. Tech B says that fuel pump volume can be affected by the condition of the fuel injectors. Who is correct?
- A.
Tech A
- B.
Tech B
- C.
Both Techs A and B
- D.
Neither Tech A nor B
- 23.A fuel pump can be tested using a lab scope and a low-amp clamp to:
- A.
Graph the current flow.
- B.
Measure the fuel pressure.
- C.
Measure the volume.
- D.
Test for pressure loss due to leaks.
- 24.The engine misfire monitor directly detects a fault by monitoring:
- A.
Exhaust emissions.
- B.
Crankshaft rpm.
- C.
Cylinder head temperature.
- D.
Transmission output shaft rpm.
- 25.The power train control module (PCM) must control a high-current fuel pump. The best actuator to use would be a:
- A.
Bipolar transistor.
- B.
MOSFET.
- C.
Relay.
- D.
Set of drivers.