Question 1

Which diesel injection system is capable of pressurizing fuel independent of engine speed?
A)HEUI (hydraulically actuated electronic unit injection)"
B)Pump-Line-Nozzle rotary injection pump"
C)EUI (Electronic Unit Injection) system
D)MUI (Mechanical Unit Injection) system"

Accepted Answer

The HEUI system uses hydraulic energy from engine oil to pressurize the fuel, allowing it to operate independently of engine speed.

Question 2

Fuel supply pressure is regulated to:
A)10-30 psi"
B)20-50 psi"
C)30-80 psi
D)80-90 psi"

Accepted Answer

The answer of Fuel supply pressure is regulated to:
A)10-30 psi"
B)20-50...

Question 3

The concept of eliminating the camshaft is simple: you use _____ to open and close the valve.
A)hydraulic pressure"
B)mechanical pressure"
C)electronic solenoid
D)spring force"

Accepted Answer

The answer of The concept of eliminating the camshaft is...

Question 4

What area of the fueling profiles represent(s) a sharp beginning of injection with a maximum quantity of fuel injected throughout the injection?
A)Square edges"
B)Upward loop"
C)Round edges
D)Downward loop"

Accepted Answer

Square edges represent a sharp beginning of injection with a maximum quantity of fuel injected throughout the injection.

Question 5

What injection strategy delivers fuel in two distinct events during one combustion cycle?
A)Pre-injection"
B)Pilot injection"
C)Split-shot injection
D)Main injection"

Accepted Answer

Split-shot injection delivers fuel in two distinct events during one combustion cycle, allowing for better control of combustion and emissions.

Question 6

This modular construction feature of HEUI (hydraulically actuated electronic unit injection) system components permits HEUI adaption to a specific engine application by simply changing the:
A)software programming"
B)injection pumps"
C)injectors
D)ECM (engine Control Module)"

Accepted Answer

The HEUI system can be adapted to specific engine applications by changing the software programming, which allows for adjustments in fuel delivery and timing without altering physical components.

Question 7

Which of the following is NOT a variation of the HEUI (hydraulically actuated electronic unit injection) injector?
A)HEUI A"
B)HEUI B"
C)HEUI Gen I
D)HEUI Gen II"

Accepted Answer

HEUI Gen I is not a variation of the HEUI injector.

Question 8

Which of the following HEUI (hydraulically actuated electronic unit injection) injectors does not use split-shot- or pilot-injection capabilities?
A)HEUI A"
B)HEUI B"
C)HEUI Gen I
D)HEUI Gen II"

Accepted Answer

The answer of Which of the following HEUI (hydraulically actuated...

Question 9

What part of the HEUI (hydraulically actuated electronic unit injection) A and B split-shot injector atomizes and distributes fuel into the combustion chamber?
A)High-voltage electric solenoid"
B)Poppet valve"
C)Intensifier piston and plunger
D)Nozzle assembly"

Accepted Answer

The nozzle assembly is responsible for atomizing and distributing the fuel into the combustion chamber in a HEUI injector system.

Question 10

During which part of the HEUI (hydraulically actuated electronic unit injection) injector injection cycle does the lower seat of the poppet valve block high-pressure oil from entering the injector?
A)Fill"
B)Injection"
C)End of injection
D)Metering"

Accepted Answer

The answer of During which part of the HEUI (hydraulically...

Question 11

Which of the following is the ability of the fuel system to adjust the quantity of fuel injected during the injection sequence?
A)Rate control"
B)Ignition delay"
C)Injection delay
D)Pressurization"

Accepted Answer

Rate control refers to the ability of the fuel system to adjust the quantity of fuel injected during the injection sequence.

Question 12

Which of the following conditions is indicated when engine oil contaminates the fuel tank of a vehicle with a HEUI engine?
A)A leaking amplifier piston O-ring."
B)A leaking cylinder head gasket."
C)A defective injection pressure regulator.
D)A leaking injector external O-ring."

Accepted Answer

A leaking injector external O-ring can allow engine oil to enter the fuel system, leading to contamination of the fuel tank in a HEUI engine.

Question 13

What is unique about the digital valve in the Gen II injector is its dependence on _____ to move the control valve.
A)magnetic induction"
B)the spinning generator"
C)PWM (Pulse Width Modulation)
D)residual magnetism"

Accepted Answer

The answer of What is unique about the digital valve...

Question 14

Which part of the Gen II injector event begins with the spool valve in the closed position, preventing oil from entering the injector?
A)Pre-fill"
B)Fill"
C)Main injection
D)End of injection"

Accepted Answer

The answer of Which part of the Gen II injector...

Question 15

Which part of the Gen II injector event energizes the open coil, moving the spool valve to the open position?
A)Pre-fill"
B)Fill"
C)Main injection
D)End of injection"

Accepted Answer

The main injection phase is when the injector is actively energized to open the spool valve, allowing fuel to be injected into the combustion chamber.

Question 16

Which of the following minimizes a rhythmic cackling noise at idle caused by pressure waves from the high-pressure pump synchronizing with injection events?
A)Dampener"
B)Pressure control valve"
C)Acoustic Wave Attenuation (AWA)
D)Snubber valve"

Accepted Answer

Acoustic Wave Attenuation (AWA) is specifically designed to minimize noise caused by pressure waves in fuel systems, which can synchronize with injection events and cause a rhythmic cackling noise at idle.

Question 17

Technician B says that Gen II injection timing can be varied by changing the specific time during crankshaft rotation to cycle the open and close coils. Technician B says to change the rate of fuel delivery, the oil pressure to the injector is electronically varied by a variable resistor. Who is right?
A)A only"
B)B only"
C)Both A and B
D)Neither A nor B"

Accepted Answer

The answer of Technician B says that Gen II injection...

Question 18

Technician A says acoustic wave attenuation (AWA) fittings in the oil manifold of some Gen II HEUI engines reduce irregular combustion noise. Technician B says split-shot injection reduces combustion noise. Who is correct?
A)Technician A"
B)Technician B"
C)Both A and B
D)Neither A nor B"

Accepted Answer

Both Technician A and Technician B are correct. Acoustic wave attenuation (AWA) fittings help reduce irregular combustion noise, and split-shot injection is a technique used to reduce combustion noise by injecting fuel in two stages.

Question 19

Which of the following is a unique feature of the HEUI HIB-300 injector?
A)Electronically balanced poppet valve"
B)Hydraulically balanced nozzle valve."
C)Low-mass poppet valve
D)High-mass poppet valve"

Accepted Answer

The answer of Which of the following is a unique...

Question 20

What is used in the wiring harness to indicate to the ECM the viscosity of oil used?
A)Removable plug"
B)Removable resister"
C)Variable resistor
D)Capacitor circuit"

Accepted Answer

The answer of What is used in the wiring harness...

Quiz 12: Heui Injection Systems

Which diesel injection system is capable of pressurizing fuel independent of engine speed?

Fuel supply pressure is regulated to:

The concept of eliminating the camshaft is simple: you use _____ to open and close the valve.

What area of the fueling profiles represent(s) a sharp beginning of injection with a maximum quantity of fuel injected throughout the injection?

What injection strategy delivers fuel in two distinct events during one combustion cycle?

This modular construction feature of HEUI (hydraulically actuated electronic unit injection) system components permits HEUI adaption to a specific engine application by simply changing the:

Which of the following is NOT a variation of the HEUI (hydraulically actuated electronic unit injection) injector?

Which of the following HEUI (hydraulically actuated electronic unit injection) injectors does not use split-shot- or pilot-injection capabilities?

What part of the HEUI (hydraulically actuated electronic unit injection) A and B split-shot injector atomizes and distributes fuel into the combustion chamber?

During which part of the HEUI (hydraulically actuated electronic unit injection) injector injection cycle does the lower seat of the poppet valve block high-pressure oil from entering the injector?

Which of the following is the ability of the fuel system to adjust the quantity of fuel injected during the injection sequence?

Which of the following conditions is indicated when engine oil contaminates the fuel tank of a vehicle with a HEUI engine?

What is unique about the digital valve in the Gen II injector is its dependence on _____ to move the control valve.

Which part of the Gen II injector event begins with the spool valve in the closed position, preventing oil from entering the injector?

Which part of the Gen II injector event energizes the open coil, moving the spool valve to the open position?

Which of the following minimizes a rhythmic cackling noise at idle caused by pressure waves from the high-pressure pump synchronizing with injection events?

Technician A says acoustic wave attenuation (AWA) fittings in the oil manifold of some Gen II HEUI engines reduce irregular combustion noise. Technician B says split-shot injection reduces combustion noise. Who is correct?

Which of the following is a unique feature of the HEUI HIB-300 injector?

What is used in the wiring harness to indicate to the ECM the viscosity of oil used?