Engine Fuel and Fuel Metering Systems Oral Practice Test

These questions are part of the practice quiz. Start practicing

• Define vapor lock and identify common contributing factors.
• What is the purpose of the dump portion of the pressurizing and dump valve?
• How can ECU timing be miscalibrated, leading to incorrect fueling?
• What are the three functions of the Venturi?
• Which option best completes: The main fuel strainers collect water and sediment, and also keep foreign matter out of the carburetor.
• What are the two most widely used fuel filters?
• During turbine engine maintenance, which indicator is primarily tracked to ensure proper speed control?
• How does a returnless fuel system differ from a traditional return-type system?
• What is the purpose of the pressurizing portion of the same valve?
• What is the purpose of a secondary filter or water separator?
• In turbocharged engines, what change is commonly made to injection pressure?
• Which statement correctly describes the carburetor-economizer system?
• Why must fuel lines have gentle slopes and no sharp curves?
• In a closed-feed injection carburetor, how is fuel metered?
• What are the two categories of turbine engine fuel pumps?
• What maintenance practices help prolong fuel metering system life?
• How does a closed-feed injection carburetor operate?
• Which faults can cause ECU fueling miscalibration when faulty?
• How does an oxygen sensor influence fuel metering in an EFI engine?
• What is a primary function of the main fuel strainers?
• What method is most often used to prevent ice in turbine engine fuel filters?
• What is the function of an accelerator pump in carbureted systems?
• Which statement describes a fixed displacement pump?
• What are the two sources for heating turbine fuel?
• Which instrument indication is used when trimming turbine engines?
• In EFI engine control, which operation uses oxygen sensor feedback to maintain the target air-fuel ratio?
• What type of pump is classified as constant (positive) displacement?
• How do fuel temperature and density affect metering calculations?
• How would you test a regulator for proper operation?
• What happens to excess fuel not required by a constant displacement pump?
• Which pump type varies discharge with engine demand?
• Which describes mass flow vs volumetric flow?
• Which of the following describes an advantage of FADEC over a hydromechanical fuel control?
• How does a rail pressure regulator's vacuum reference function in maintaining rail pressure?
• What indicates when the mixture is moved to cutoff and RPM drops immediately to zero?
• Which turbine component injects fuel into the combustion area?
• In turbine fuel control systems, which type is most accurate?
• What is the action of a float-type carburetor accelerating system when the throttle is opened quickly?
• What is observed when idle mixture is correctly set and the idle cutoff is engaged?
• Which component in a turbine engine fuel system is most prone to ice formation?
• Which parameter is detected by the turbine engine fuel control unit?
• Why may an electric boost pump be used in an APU?
• Which sensors faults are commonly cited as causing ECU fueling miscalibration?
• In a modern EFI system, what parameter is kept at a set value by regulation?
• Which component is designed to keep foreign matter out of the carburetor?
• Explain internal vs external fuel pressure regulators.
• What are common causes of a high rail pressure condition?
• Where does the pressure injection carburetor obtain its fuel pressure?
• What is the purpose of a turbine engine duplex fuel nozzle?
• What is another type of fuel metering system used on reciprocating engines other than carburetors?
• Why is vapor lock serious?
• What problem occurs if the idle mixture is set too rich?
• Which component references intake manifold vacuum to adjust rail pressure in many systems?
• What is the difference between a fuel filter and a water separator in aviation fuel systems?
• If the air-fuel ratio is enriched above 0.080, what happens?
• What is a common risk of fuel line heat soak and how is it mitigated?
• Why is clean fuel essential for metering accuracy?
• A turbine fuel control system that has no electronic interface is classified as which type?
• What is a common sign of injector leakage that can be observed during a pressure test?
• Which statement describes why mass-based fueling is preferred?
• What is the primary function of a fuel metering system in an internal combustion engine?
• Which statement about vapor lock is true?
• Which statement describes the purpose of using bleed air and engine oil in turbine fuel systems?
• What operates an automatic mixture control?
• How does intake manifold vacuum influence rail pressure in a vacuum-referenced regulator?
• What does the use of fuel boost pumps help prevent?
• Why is a return line used in many fuel systems?
• What unit in a turbine engine fuel system is susceptible to the formation of ice?
• Which component in a turbine engine is designed to produce two spray patterns?
• What keeps a dual-element constant displacement fuel pump operating if one gear seizes?
• What is the purpose of a traditional fuel system's return path?
• Why is a low-pressure filter installed between the supply tanks and the engine fuel system?
• Which of the following describes common symptoms of a faulty or leaking injector?
• Which statement is true about the Venturi in a carburetor?
• Which symptom indicates a potential fuel metering issue during idle?
• Which sensor data should be verified when confirming metering corrections after repair?
• A turbine fuel control system without electronic interface is known as what type?
• If engine demand increases, which pump type adjusts discharge accordingly?
• Which test method is used to detect leaking injectors by monitoring rail pressure while isolating the injector?
• When functioning correctly, what is the effect of fuel boost pumps on the fuel system?
• How can you differentiate fuel starvation from ignition problems?
• What is density compensation in engine fuel metering intended to do?
• What are the two types of carburetors most commonly used on small reciprocating engines?
• Which two mesh sizes are the most widely used for fuel filters?
• What is the function of the mixture control on float-type carburetors?
• What requirement must reciprocating fuel metering systems meet?
• Which component is primarily responsible for removing water from fuel before it reaches the carburetor?
• Which maintenance action directly helps prevent fuel leaks and ensure metering accuracy?
• What does cold-start enrichment do?
• Which statement about main fuel strainers is true?
• If rail pressure is too low, what is a likely outcome?
• Where does a pressure injection carburetor obtain fuel pressure?
• What is the purpose of a carburetor-economizer system?
• How does direct injection differ from port injection in metering?
• How does O2 sensor feedback operate in closed-loop fueling?
• On a reciprocating engine, what is the injection carburetor that employs a closed feed system called?
• What is the best stoichiometric air-fuel mixture?
• Which design helps reduce vaporization risk from hot return fuel?
• What is the role of the fuel pump relay?
• How is fuel continuity checked during maintenance?
• What safety feature becomes active if a micron filter becomes clogged?
• In a turbine engine fuel system, the high-pressure filter is installed between which two components?
• Which condition is most likely to contribute to vapor lock?
• At what point does the fuel mix with the air in a fuel injection engine?
• Which symptom would most likely indicate that the idle mixture is too rich?
• What is injector duty cycle and how does it relate to engine load?
• What should be looked for during inspection of an engine-driven fuel pump?
• What is the role of a pressure relief valve in some fuel systems?
• What type of engine-driven fuel pump is widely used other than gear and piston pumps?
• Which device in the EEC system senses the power lever angle?
• How can you identify a clogged injector during testing?
• How do fuel temperature and ambient temperature influence density and metering?
• Which option is NOT one of the three basic types of turbine fuel control units?
• How do you verify proper fuel metering after a repair?
• Which component is primarily responsible for adjusting rail pressure in response to engine demand?
• Which statement about the primary role of the turbine fuel control unit is accurate?
• How does the MAF sensor influence metering?
• A vapor lock condition can lead to which of the following?
• What is the fundamental difference between a carburetor-type metering system and an electronic fuel injection system?
• Which statement describes the role of the duplex nozzle in turbine engines?
• Which component compatibility may be affected by ethanol blends in fuel?
• Which parameter is detected by the turbine engine fuel control unit?
• Which of the following is not a cause of fuel vapor lock?
• Which of the following is a component of the EEC system?
• What are the three most common types of fuel filters used?
• What is the correct procedure to measure rail pressure with a Schrader-type test port?
• Which statement best describes the spray strategy difference between direct injection and port injection?
• How does boosting affect metering?
• NOT among the three most common fuel filters used?
• Which component meters the fuel flow in a FADEC system?
• What are the purposes of fuel selector valves?
• What type of fuel pump can vary the discharge regardless of speed?
• Name two major components of a supervisory electronic engine control?
• Which of the following is an FADEC advantage?
• What effects do ethanol-blended fuels have on metering?
• What are the purposes of the main fuel strainers?
• Which part of the duplex nozzle fuel system divides flow into primary and secondary manifolds?
• Why is it important to check for vacuum leaks during metering diagnostics?
• In a constant displacement fuel system, where does the bypassed excess fuel go?
• What is the first thing to check if a float-type carburetor engine fails to develop full power?
• Where is a typical automotive fuel pump located and what does it do?
• When troubleshooting a stumble during acceleration attributed to fuel metering, which checks are recommended?
• How does a faulty injector affect engine combustion stability?
• What is the primary function of a turbine engine fuel control unit?
• Where is an additional high-pressure fuel filter installed?
• Which statement is true about the two categories of turbine engine fuel pumps?
• What is the purpose of fuel filters and water separators?
• How do you check a fuel injector's spray pattern?
• What are common causes of a low rail pressure condition?
• How can you test for a leaking injector without removing it?
• What indicates a healthy injector spray pattern?
• When does a carburetor economizer system needle valve begin to open?
• What is the function of a flow divider (spider) in port fuel injection?
• Which design principle helps prevent vapor lock in fuel lines?
• Which pump would be most suitable for an engine with highly variable fuel demands?
• What are the advantages of direct fuel injection over carburetor systems?
• What position of a pressure injection carburetor manual mixture control would stop engine operation?
• What data do modern metering systems primarily base fueling on?
• What is one purpose of the return line in the fuel system besides pressure regulation?
• What is the purpose of the regulator's vacuum reference in relation to engine load?
• Which statement describes a method to prevent icing in turbine engine fuel systems?
• What type of fuel boost pump is commonly used?
• What problem is caused by an excessively rich mixture at idle in a reciprocating engine?
• Which safety precaution should be followed when servicing fuel metering components?
• Which device is designed to vary the amount of fuel delivered per revolution?
• Particles of rubber in a mainline strainer are early warnings of what?
• What is the purpose of the fuel pressurizing valve?
• What is the purpose of a fuel metering unit (FMU) in certain engines?
• What is the RPM indication when an idle mixture is set correctly and the mixture control is placed to idle cutoff?
• How is rail pressure typically maintained in a modern EFI system?
• Why is rail pressure important for direct injection systems?
• Which of the following is an advantage of FADEC over hydromechanical fuel control?
• Why should engine RPM be accelerated periodically when making carburetor adjustments?
• What is the likely cause of fuel leaking from the carburetor discharge nozzle when the engine is not running?
• The low-pressure filter between the supply tanks and the engine serves to protect which components?
• Which filtration configuration is commonly used to protect fuel metering components from debris and water?
• What are the three components of the EEC system?
• What is a recommended method to observe injector spray pattern?
• Which of the following are causes of fuel vapor lock?