Engine Performance 1 Final UPDATED
Questions and CORRECT Answers
Throttle body fuel injection has fuel pressure in which range? - CORRECT ANSWER - 9-13 psi
What purpose does the MAF serve? - CORRECT ANSWER - sense incoming air volume
T/F A General Motors oil pressure switch is a safety device designed to shut off the fuel pump if oil
pressure goes away. - CORRECT ANSWER - True
T/F Fuel lines are often in stock at parts stores for a large variety of vehicles. - CORRECT
ANSWER - False
Technician A says that if the engine stalls and the ignition switch is on, the one-way check valve prevents
fuel flow from the pump to the fuel filter and fuel system. Technician B says that when the engine is shut
off, the one-way check valve prevents fuel flow from the underhood fuel system components into the fuel
pump and tank. Who is correct? - CORRECT ANSWER - Technician B
Technician A says that O2 sensors will not produce good data until they reach operating temperature.
Technician B says that an O2 sensor heater is used to warm the exhaust entering the catalytic conveter.
Who is right? - CORRECT ANSWER - Technician A
T/F On many vehicles the fuel pump is directly powered by the PCM. - CORRECT ANSWER -
False
Which of the following is not an advantage of natural gas fueled vehicles? - CORRECT
ANSWER - Wide availability of CNG
Technician A says fuel pumps can be checked for amperage draw and current waveform. Technician B
says a low amp probe is connected in series with the circuit being tested. Who is correct? - CORRECT
ANSWER - Technician A
,Technician A says when removing a stubborn fuel line, try to pull it apart as hard as possible. Techncian
B says when removing a stubborn metal fuel line that heating the fittings with a propane torch will help.
Who is right? - CORRECT ANSWER - Neither
Technician A says light taps on the bottom of the fuel tank where the fuel pump is located with a rubber
mallet may help diagnose a bad in-tank pump. Technician B says that a fuel pump may run almost
competly silent if there is no fuel in the tank. Who is right? - CORRECT ANSWER - Both
T/F A hammer and a punch can be used to remove the lock ring on some fuel pumps inside of the fuel
tank. - CORRECT ANSWER - True
T/F A vehicle will be in closed loop when the vehicle is cold. - CORRECT ANSWER - False
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? - CORRECT ANSWER - Both
Ethanol is added to fuel in which percentage the most? - CORRECT ANSWER - 10%
Which fuel system is capable of firing more than one fuel injector or one bank of injectors at a time? -
CORRECT ANSWER - MPFI
When the pressure in the intake manifold increases the fuel pressure regulator on a port fuel injection
system: - CORRECT ANSWER - Increases fuel pressure
The simplest hydrocarbon is? - CORRECT ANSWER - CH4
The lines that feed the high pressure fuel injectors in a DFI system have to be made from which material?
- CORRECT ANSWER - Stainless Steel
T/F Fuel pressure should drop to close to 0 (zero) after the engine is shut off to prevent fuel leaks. -
CORRECT ANSWER - False
, T/F The octane number indicates the antiknock quality of gasoline. - CORRECT ANSWER - True
Technician A says reducing spark advance can cause spark knock. Technician B says excessive carbon
deposits can cause spark knock. Who is correct? - CORRECT ANSWER - Technician B
T/F The filter with the finest filtering ability in a fuel injection system is located inside of the fuel
injector. - CORRECT ANSWER - True
T/F Warm fuel leads to more evaporative emissions. - CORRECT ANSWER - True
What is the term for using pressure, or vacuum to break longer hydrocarbon chains into shorter, more
useful chains? - CORRECT ANSWER - cracking
When a vacuum operated fuel pressure regulator adjusts fuel pressure it will change no more than how
much pressure? - CORRECT ANSWER - 5-10 psi
The inertia switch is located in the ________ on most Ford cars. - CORRECT ANSWER - In trunk
T/F A fuel damper may be used to help smooth out fuel pressure pulses caused by the firing of the
injectors. - CORRECT ANSWER - True
Which fuel additive was added to increase octane but damaged the catalytic converter? - CORRECT
ANSWER - Tetraethyllead
T/F Fuel system pressure should be relieved with the engine running. - CORRECT ANSWER -
False
T/F The Dodge Durangos with extended crank conditions that the instructor talked about had bad fuel
pump return check valves. - CORRECT ANSWER - True
Questions and CORRECT Answers
Throttle body fuel injection has fuel pressure in which range? - CORRECT ANSWER - 9-13 psi
What purpose does the MAF serve? - CORRECT ANSWER - sense incoming air volume
T/F A General Motors oil pressure switch is a safety device designed to shut off the fuel pump if oil
pressure goes away. - CORRECT ANSWER - True
T/F Fuel lines are often in stock at parts stores for a large variety of vehicles. - CORRECT
ANSWER - False
Technician A says that if the engine stalls and the ignition switch is on, the one-way check valve prevents
fuel flow from the pump to the fuel filter and fuel system. Technician B says that when the engine is shut
off, the one-way check valve prevents fuel flow from the underhood fuel system components into the fuel
pump and tank. Who is correct? - CORRECT ANSWER - Technician B
Technician A says that O2 sensors will not produce good data until they reach operating temperature.
Technician B says that an O2 sensor heater is used to warm the exhaust entering the catalytic conveter.
Who is right? - CORRECT ANSWER - Technician A
T/F On many vehicles the fuel pump is directly powered by the PCM. - CORRECT ANSWER -
False
Which of the following is not an advantage of natural gas fueled vehicles? - CORRECT
ANSWER - Wide availability of CNG
Technician A says fuel pumps can be checked for amperage draw and current waveform. Technician B
says a low amp probe is connected in series with the circuit being tested. Who is correct? - CORRECT
ANSWER - Technician A
,Technician A says when removing a stubborn fuel line, try to pull it apart as hard as possible. Techncian
B says when removing a stubborn metal fuel line that heating the fittings with a propane torch will help.
Who is right? - CORRECT ANSWER - Neither
Technician A says light taps on the bottom of the fuel tank where the fuel pump is located with a rubber
mallet may help diagnose a bad in-tank pump. Technician B says that a fuel pump may run almost
competly silent if there is no fuel in the tank. Who is right? - CORRECT ANSWER - Both
T/F A hammer and a punch can be used to remove the lock ring on some fuel pumps inside of the fuel
tank. - CORRECT ANSWER - True
T/F A vehicle will be in closed loop when the vehicle is cold. - CORRECT ANSWER - False
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? - CORRECT ANSWER - Both
Ethanol is added to fuel in which percentage the most? - CORRECT ANSWER - 10%
Which fuel system is capable of firing more than one fuel injector or one bank of injectors at a time? -
CORRECT ANSWER - MPFI
When the pressure in the intake manifold increases the fuel pressure regulator on a port fuel injection
system: - CORRECT ANSWER - Increases fuel pressure
The simplest hydrocarbon is? - CORRECT ANSWER - CH4
The lines that feed the high pressure fuel injectors in a DFI system have to be made from which material?
- CORRECT ANSWER - Stainless Steel
T/F Fuel pressure should drop to close to 0 (zero) after the engine is shut off to prevent fuel leaks. -
CORRECT ANSWER - False
, T/F The octane number indicates the antiknock quality of gasoline. - CORRECT ANSWER - True
Technician A says reducing spark advance can cause spark knock. Technician B says excessive carbon
deposits can cause spark knock. Who is correct? - CORRECT ANSWER - Technician B
T/F The filter with the finest filtering ability in a fuel injection system is located inside of the fuel
injector. - CORRECT ANSWER - True
T/F Warm fuel leads to more evaporative emissions. - CORRECT ANSWER - True
What is the term for using pressure, or vacuum to break longer hydrocarbon chains into shorter, more
useful chains? - CORRECT ANSWER - cracking
When a vacuum operated fuel pressure regulator adjusts fuel pressure it will change no more than how
much pressure? - CORRECT ANSWER - 5-10 psi
The inertia switch is located in the ________ on most Ford cars. - CORRECT ANSWER - In trunk
T/F A fuel damper may be used to help smooth out fuel pressure pulses caused by the firing of the
injectors. - CORRECT ANSWER - True
Which fuel additive was added to increase octane but damaged the catalytic converter? - CORRECT
ANSWER - Tetraethyllead
T/F Fuel system pressure should be relieved with the engine running. - CORRECT ANSWER -
False
T/F The Dodge Durangos with extended crank conditions that the instructor talked about had bad fuel
pump return check valves. - CORRECT ANSWER - True
