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WorksheetsEFI Systems test
Total questions: 49
Worksheet time: 25mins
What is one of the disadvantages of fixed jet carburetors compared to Electronic Fuel Injection (EFI) systems?
Fixed jet carburetors use fuel more efficiently
Fixed jet carburetors make turn key operation
Fixed jet carburetors have lower overall emissions
Fixed jet carburetors don't have the ability to deal with all changing operating parameters running engines encounter
Which of the following is an advantage of using EFI in modern outboards?
Higher overall emissions
Less efficient use of fuel
Ability to deal with changing operating parameters
Reliance on motor's throttle valve opening
What does EFI stand for?
Electronic Fuel Injection
Efficient Fuel Intake
Engine Fuel Indicator
Electronic Filter Integration
What type of device is a fuel injector?
Hydraulic device
Electro-magnetic fueling device
Mechanical lever
Manual pump
What controls the operation of a fuel injector?
The vehicle's battery
The electronic control module (ECM)
The fuel pump
The engine's pistons
What happens when the injector's electrical circuit is completed (turned ON)?
The injector is deactivated
The fuel is blocked from passing through the injector
Pressurized fuel is allowed to pass through the injector for a specific period
The spring tension closes the passageway
What occurs after the allotted time ON for the fuel injector?
The ECM shuts down the entire engine
The fuel delivery continues indefinitely
The ECM opens (turns OFF) the electrical circuit, and fuel delivery ends
The battery takes over the operation of the injector
What takes over to close the fuel injector's passageway when the ECM turns OFF the electrical circuit?
Hydraulic pressure
Engine vacuum
Spring tension
Manual intervention
What factors are considered in the standard control position for fuel injection rate and timing?
Engine Speed and Throttle position
Atmospheric pressure and Temperature
Shift position and Oil pressure
Cooling water temperature and Intake pressure
What is the term used to describe adjustments made to the fuel injection amount due to varying environmental and operational conditions?
Standard control position
Injection amount
Correction
Cruising
What does the manifold absolute pressure sensor (MAP) act as in the Speed Density Method of air measurement?
A throttle position sensor
An engine speed sensor
An air pressure sensor
A flow meter
What additional information does the Throttle Speed Method initially activate and report to the ECU?
The engine rpm and throttle opening
The barometric pressure reading
The manifold absolute pressure
The air temperature
Which of the following is NOT an input for calculating the Basic Injection Quantity in EFI systems?
Engine RPM
Throttle Position
Atmospheric Pressure
Water Temperature
What does direct measurement of mass flow directly measure?
The temperature of the engine
The airflow entering the engine
The speed of the engine
The fuel level in the engine
Why is direct measurement of mass flow not currently used on Yamaha outboards?
Because it is not accurate
Due to electrical issues
Because of space limitations
Due to the high cost
What does the direct measurement of speed density use to determine the amount of air entering the motor?
Exhaust gas temperature and vehicle speed
Intake pressure sensor and engine speed
Fuel level and air temperature
Oil pressure and battery voltage
Who initially developed the Single Point Injection (SPI) system?
The aerospace industry
The auto industry
The marine industry
The motorcycle industry
What is the Single Point Injection (SPI) system primarily effective in reducing?
Fuel consumption
Engine noise
Emissions
Engine size
How many injectors does the Single Point Injection (SPI) system have?
Two
Four
One
Six
Where is the injector mounted in a Single Point Injection (SPI) system?
On the cylinder head
On the exhaust manifold
On the intake manifold where pipes meet together
On the fuel tank
What is a basic characteristic of the Single Point Injection (SPI) system's operation?
Complex starting procedure
Manual fuel mixture adjustment
Easy starting and turn key operation
High maintenance requirements
Compared to single port systems, multi-point injection systems are:
Less expensive to produce
The same price to produce
More expensive to produce
Not used in modern engines
What is a feature of revised, improvised multi-point (MP) units?
A single injector for all cylinders
No injectors are used
A dedicated injector for each cylinder
Less efficient fuel usage
What are the benefits of multi-point injection systems?
Decreases engine response times and increases emissions
Improves engine response times and increases emissions
Worsens overall performance and efficiency
Improves engine response times, reduces emissions, enhances overall performance & efficiency
When is simultaneous multi-point injection used?
When the engine is turned off
During regular driving conditions
When extra fuel is required such as under hard acceleration
Only during vehicle maintenance
What do most EFI engines do if fuel demand is great enough?
Shut down to prevent damage
Switch to a diesel fuel system
Batch fire
Activate a secondary fuel pump
What happens to the injection process once acceleration is over in simultaneous multi-point injection?
It stops completely
It reverts to standard injection
It doubles the amount of fuel injected
It switches to manual injection
When does simultaneous multi-point injection activate all injectors at the same time?
During high-speed driving
When the engine is idling
During cold start and acceleration
After the engine has warmed up
What is the purpose of camshaft timing in Multi-Point Injection systems?
To increase fuel consumption
To improve engine noise
To prevent wasted fuel
To decrease engine power
How often do the injectors fire in a Multi-Point Injection system?
Every full revolution of the crankshaft
Every half revolution of the crankshaft
Every quarter revolution of the crankshaft
With every piston activation
How much fuel is injected with every activation in a Multi-Point Injection system?
1/4 of required fuel
1/2 of required fuel
3/4 of required fuel
Full required fuel
What type of outboards are multi-point injection systems used by?
The oldest outboards
The latest, generally most sophisticated outboards
Manual outboards
Single-point injection outboards
How do injectors operate during normal operation in a multi-point injection system?
Injectors fire simultaneously
Injectors fire independently of each other and sequentially
Injectors fire all at once at the beginning of each cycle
Injectors do not fire during normal operation
How often does each injector fire in a multi-point injection system during normal operation?
Once per crankshaft revolution
Once per two crankshaft revolutions when all required fuel injected
Twice per crankshaft revolution
Once per four crankshaft revolutions
What happens to the injectors under hard acceleration in a multi-point injection system?
Injectors shut off completely
Injectors fire sequentially at a slower rate
Injectors have batch fire option
Injectors fire continuously without interruption
What does the Engine ECM do in an EFI System?
It detects throttle valve opening angle
It determines engine operating conditions based on input signals from sensors
It detects engine speed and crankshaft angle
It transmits throttle valve position
What is the function of the Pulser coil in an EFI System?
It determines engine operating conditions
It detects throttle valve opening angle
It detects engine speed and crankshaft angle
It transmits control signals to each actuator
What does the Throttle Position Sensor (TPS) detect in an EFI System?
It determines engine operating conditions
It transmits control signals to each actuator
It detects engine speed and crankshaft angle
It detects throttle valve opening angle
What does the intake air pressure/temperature sensor in an EFI system detect?
Exhaust gas temperature
Intake air temperature and pressure
Engine oil temperature
Fuel pressure
What is the function of the oil pressure switch in an EFI system?
Detects fuel level
Monitors battery voltage
Detects oil pressure
Measures coolant level
What does the thermo sensor in an EFI system detect?
Air flow rate
Water temperature
Oil quality
Brake fluid pressure
What does the shift position switch in an EFI system detect?
Gear engagement
Vehicle speed
Neutral position
Clutch engagement
What is the function of a fuel injector in an EFI system?
It produces high voltage for the spark plug.
It adjusts intake air distribution to the engine.
It injects fuel.
It pressurizes and feeds fuel to fuel rails for injection.
What does the ignition coil do in an EFI system?
It injects fuel.
It produces high voltage to ignite a spark plug.
It adjusts intake air distribution to the engine when the throttle valve is fully closed.
It pressurizes and feeds fuel to fuel rails for injection.
What is the role of the high-pressure fuel pump in an EFI system?
It injects fuel.
It produces high voltage for the spark plug.
It adjusts intake air distribution to the engine.
It pressurizes and feeds fuel to fuel rails for injection.
What does the ISC valve do in an EFI system?
It injects fuel.
It produces high voltage to ignite a spark plug.
It pressurizes and feeds fuel to fuel rails for injection.
It adjusts intake air distribution to the engine when the throttle valve is fully closed.
What is the function of the vapor shut-off valve in an EFI System?
It detects engine knocking
It controls the amount of vapor gas sent from VST to intake system to be reburned
It detects water accumulated in fuel filter
It regulates the fuel pressure
What does the knock sensor do in an EFI System?
It controls the amount of vapor gas sent from VST to intake system to be reburned
It detects water accumulated in fuel filter
It detects engine knocking
It regulates the engine temperature
What is the purpose of the water detection switch in an EFI System?
It detects engine knocking
It controls the amount of vapor gas sent from VST to intake system to be reburned
It regulates the fuel pressure
It detects water accumulated in fuel filter
