Diesel Fuel Injections Basics

What drivability problem would occur if a governor spring were to break?

excess RPM

engine would quit

increased power

decreased power

Correct! Wrong!

Technician A says that secondary fuel filters are usually in the range of 5-7 microns. Technician B says that primary fuel filters are usually in the range of 15-25 microns. Who is correct?

Technician A

Technician B

Both A and B

Neither A nor B

Correct! Wrong!

Technician A says that the primary fuel filter is usually on the suction side of the transfer pump. Technician B says that the secondary fuel filter is usually on the suction side of the transfer pump. Who is correct?

Technician A

Technician B

Both A and B

Neither A nor B

Correct! Wrong!

Technician A says that a fuel system must supply the correct quantity of fuel and time the fuel delivery. Technician B says that a fuel system must control the delivery rate and distribute the fuel evenly into the cylinder. Who is correct?

Technician A

Technician B

Both A and B

Neither A nor B

Correct! Wrong!

How will a diesel engine perform when operating on a fuel with a high cetane rating in the summer time?

less power

more power

no change in power

possible pump damage

Correct! Wrong!

What controls the maximum pressure in a high pressure fuel line?

rack

plunger

needle and seat assm

delivery valve

Correct! Wrong!

When working with injection nozzles you should:

keep hands out of the path of the high pressure spray

wet hand with fuel before handling precision parts

keep parts and work area extremely clean

all of the above

Correct! Wrong!

Technician A says that when checking injection nozzles you should check the cracking and closing pressures. Technician B says that you should check the spray pattern. Who is correct?

Technician A

Technician B

Both A and B

Neither A nor B

Correct! Wrong!

When mounting a fuel injection pump to an engine and adjusting the fuel pump drive so that pins will enter their respective holes in the flywheel and fuel pump, you are said to be ___________ the fuel pump to the engine.

phasing

metering

calibrating

timing

Correct! Wrong!

What will occur if the cracking pressure in a nozzle is too low?

early injection

late injection

uncontrolled burn

all of the above

Correct! Wrong!

The most common injection nozzle used with direct injection is the:

multi-hole nozzle

pintle nozzle

pintaux nozzle

delay nozzle

Correct! Wrong!

On a rail design fuel system, what is the purpose of the restricted fitting in the return fuel line?

acts as a relief valve for the transfer pump

maintains transfer pump pressure

prevents injectors from receiving fuel pressure

keeps the fuel lines from draining back to the fuel tank

Correct! Wrong!

Which fuel injection system is used by Detroit 2 cycle diesels?

pressure timed

unit injectors

sleeve metering

distributor type

Correct! Wrong!

One advantage to a unit injection system is:

the pump provides variable pressure

there are no high pressure lines

injection pressure never exceeds 1200 psi

the spray pattern changes with engine RPM

Correct! Wrong!

To determine if the fuel transfer pump for an injection system is operating efficiently you must test for:

pressure, volume and spill back

pressure, flow and volume

speed, air bubbles and pressure

pressure only

Correct! Wrong!

On an engine equipped with a non-electronic diesel fuel system, when an operator moves the throttle through the speed ranges, he is altering the governor's.

flyweight position

spring tension

torque spring

buffer screw

Correct! Wrong!

On a fuel injection pump utilizing the port and helix system, what determines the position of the control edge of the helix?

rack

sleeve

plunger

delivery valve

Correct! Wrong!

On an in-line fuel injection pump utilizing the port and helix system, what maintains pressure for a rapid rise and fall of injection pressures?

rack assm

Sleeve

injector nozzle

delivery valve

Correct! Wrong!

On a test bench, when a technician adjusts a fuel pump so that each injection event occurs exactly the correct number of degrees apart he is said to be _________________ the fuel pump.

calibrating

timing

phasing

metering

Correct! Wrong!

When a technician adjusts a fuel pump, when the rack rotates the plunger so that the vertical groove is aligned with the fill port, the pump is said to be in the:

calibrating

timing

phasing

metering

Correct! Wrong!

On a port and helix fuel pump, when the rack rotates the plunger so that the vertical groove is aligned with the fill port, the pump is said to be in the:

full fuel position

peak torque position

no fuel position

idle position

Correct! Wrong!

On a port and helix fuel pump system, when the rack rotates the plunger so that the narrowest part of the helix is aligned with the fill/spill port, the pump is said to be in the:

full fuel position

peak torque position

no fuel position

idle position

Correct! Wrong!

Injection nozzles that open with the needle valve moving away from the combustion chamber are said to be:

inward opening

outward opening

chattering

cooking

Correct! Wrong!

An injection nozzle that has one main spray hole and an extra hole that directs its spray at the part of the combustion chamber is known as a _____________nozzle.

delay

pintaux

hole

differential

Correct! Wrong!

A fuel pressure gauge test on an engine may indicate:

transfer pump pressure

fuel filter condition

the recommended pressure at an idle and run positions

all of the above

Correct! Wrong!

An operator complains that his engine idle is about 100 RPM more that it was a few days ago, on his Detroit Diesel 8-92 2 cycle engine, what is the likely problem?

injectors out of adjustment

governor gap out of adjustment

one injector stuck in the full fuel position

all of the above

Correct! Wrong!

On some distributor type fuel systems, timing may be adjusted by:

injector height adjustment

metering valve adjustment

rotating the fuel pump at its mounting

timing may not be altered

Correct! Wrong!

In a distributor type fuel pump, the cam ring and plungers produce:

low pressure fuel

high pressure fuel

high fuel volume

low fuel volume

Correct! Wrong!

Before removing a fuel injection pump, you must locate the engine for timing and position so that the injection pump can be reinstalled in the correct position.

True

False

Correct! Wrong!

When servicing injectors, you should always remember to:

clean the parts in new fuel

never interchange plungers and barrels

test them for operation before cleaning

all of the above

Correct! Wrong!

Injector timing on the Detroit unit injector system is considered to be correct when:

the engine runs without smoke

the engine does not run-on when turned off

the flat end of the timing gauge wipes oil off the follower

the rack control lever bottoms on the rack

Correct! Wrong!

A distributor type pump uses a _________________ to control the delivery rate:

rack and rotating plungers

fuel pressure regulator

port and helix

metering valve

Correct! Wrong!

In a diaphragm type fuel transfer pump, the maximum possible pressure output would be limited by:

the speed of the engine

the arm pushing on the diaphragm

the spring pushing on the diaphragm

the height of the cam lobe

Correct! Wrong!

Caterpillar capsule type injectors are adjusted:

on the VS mark

at TDC

at the factory

when the exhaust valves are open

Correct! Wrong!

To check which cylinder is missing on an engine equipped with an inline injection pump and nozzles in the cylinder head, you would:

hold the injector plunger down on each cylinder (one at a time) while the engine is running

crack each fuel line to the nozzles (one at a time) while the engine is running

perform a compression test on each cylinder to see which is the low one

disconnect the glow plug wire from each cylinder (one at a time) to see which one is missing

Correct! Wrong!

A fuel transfer pump:

pump more fuel than is required by the engine

pumps just as much fuel as required by the engine

is centrifugal

is only required in order to prime the filters

Correct! Wrong!

Often the best volumetric efficiency of an engine is at the RPM where it develops peak torque.

True

False

Correct! Wrong!

Placing shims between the engine block and the ______________, will alter the timing on 855 cu.in. Cummins six cylinder engine.

rocker box

cylinder head

cam follower housings

accessory drive

Correct! Wrong!

The most common type of combustion chamber used in large trucks today is the:

pre-combustion

direct injection

turbulence

air cell

Correct! Wrong!

What engine performance measurement is found by using the following formula: Torque x RPM divided by 5252:

torque

horsepower

mean effective pressure

volumetric efficiency

Correct! Wrong!

As compared to a direct injection chamber, a engine equipped with pre-combustion chambers will:

have lower combustion pressures

burn a wide range of fuel

have lower injection pressures

all of the above are correct

Correct! Wrong!

On a diesel injected engine, if a delivery valve does not seat properly, the engine would:

show no noticeable change

miss

stall

go to maximum governed RPM

Correct! Wrong!

Technician A says that a fuel injection pump with port and helix system uses a mechanical actuated injector. Technician B says that a distributor type fuel system uses a hydraulically actuated injector. Who is correct?

Technician A

Technician B

Both A and B'

Neither A nor B

Correct! Wrong!

Technician A says that a Bosch and a Detroit fuel system both use a mechanical type injector. Technician B says that a Bosch and a Detroit fuel system both use a port and helix system. Who is correct?

Technician A

Technician B

Both A and B

Neither A nor B

Correct! Wrong!

Which of the following systems would a Cummins engine use to control the fuel injections to the engine?

pressure timed

port and helix

sleeve metering

distributor

Correct! Wrong!

The primary fuel filter on an engine is on the ___________ side of the fuel pump.

pressure

suction

outlet

fuel return

Correct! Wrong!

In a distributor type fuel pump, a hydraulically actuated plunger and counter-balancing spring, automatically moves the__________________ back and forth with changing engine speeds, to alter the injections timing advance.

metering valve

cam ring

rollers and plungers

charging ring

Correct! Wrong!

To locate a faulty injector on a Cummins PT injection system you should:

loosen the lines one at a time and listen for a change in engine performance

hold each injector on its seal and listen for a change in engine performance

loosen the injector adjusting screw lockout and back out the injector while listening to the engine

open the bleed line on each injector and listen for a change in engine performance

Correct! Wrong!

The resistance of a liquid to flowing is called?

intensity

viscosity

volatility

cetane

Correct! Wrong!

There is a delay between the time that fuel is injected into the cylinder and the time that ignition by the hot air takes place. The duration of this delay is expressed as a(n) _____________number:

octane

cetane

distillation end point

viscosity

Correct! Wrong!

What drivability problem would occur if a governor spring were to break?

Technician A says that secondary fuel filters are usually in the range of 5-7 microns. Technician B says that primary fuel filters are usually in the range of 15-25 microns. Who is correct?

Technician A says that the primary fuel filter is usually on the suction side of the transfer pump. Technician B says that the secondary fuel filter is usually on the suction side of the transfer pump. Who is correct?

Technician A says that a fuel system must supply the correct quantity of fuel and time the fuel delivery. Technician B says that a fuel system must control the delivery rate and distribute the fuel evenly into the cylinder. Who is correct?

How will a diesel engine perform when operating on a fuel with a high cetane rating in the summer time?

What controls the maximum pressure in a high pressure fuel line?

When working with injection nozzles you should:

Technician A says that when checking injection nozzles you should check the cracking and closing pressures. Technician B says that you should check the spray pattern. Who is correct?

When mounting a fuel injection pump to an engine and adjusting the fuel pump drive so that pins will enter their respective holes in the flywheel and fuel pump, you are said to be ___________ the fuel pump to the engine.

What will occur if the cracking pressure in a nozzle is too low?

The most common injection nozzle used with direct injection is the:

On a rail design fuel system, what is the purpose of the restricted fitting in the return fuel line?

Which fuel injection system is used by Detroit 2 cycle diesels?

One advantage to a unit injection system is:

To determine if the fuel transfer pump for an injection system is operating efficiently you must test for:

On an engine equipped with a non-electronic diesel fuel system, when an operator moves the throttle through the speed ranges, he is altering the governor's.

On a fuel injection pump utilizing the port and helix system, what determines the position of the control edge of the helix?

On an in-line fuel injection pump utilizing the port and helix system, what maintains pressure for a rapid rise and fall of injection pressures?

On a test bench, when a technician adjusts a fuel pump so that each injection event occurs exactly the correct number of degrees apart he is said to be _________________ the fuel pump.

When a technician adjusts a fuel pump, when the rack rotates the plunger so that the vertical groove is aligned with the fill port, the pump is said to be in the:

On a port and helix fuel pump, when the rack rotates the plunger so that the vertical groove is aligned with the fill port, the pump is said to be in the:

On a port and helix fuel pump system, when the rack rotates the plunger so that the narrowest part of the helix is aligned with the fill/spill port, the pump is said to be in the:

Injection nozzles that open with the needle valve moving away from the combustion chamber are said to be:

An injection nozzle that has one main spray hole and an extra hole that directs its spray at the part of the combustion chamber is known as a _____________nozzle.

A fuel pressure gauge test on an engine may indicate:

An operator complains that his engine idle is about 100 RPM more that it was a few days ago, on his Detroit Diesel 8-92 2 cycle engine, what is the likely problem?

On some distributor type fuel systems, timing may be adjusted by:

In a distributor type fuel pump, the cam ring and plungers produce:

Before removing a fuel injection pump, you must locate the engine for timing and position so that the injection pump can be reinstalled in the correct position.

When servicing injectors, you should always remember to:

Injector timing on the Detroit unit injector system is considered to be correct when:

A distributor type pump uses a _________________ to control the delivery rate:

In a diaphragm type fuel transfer pump, the maximum possible pressure output would be limited by:

Caterpillar capsule type injectors are adjusted:

To check which cylinder is missing on an engine equipped with an inline injection pump and nozzles in the cylinder head, you would:

A fuel transfer pump:

Often the best volumetric efficiency of an engine is at the RPM where it develops peak torque.

Placing shims between the engine block and the ______________, will alter the timing on 855 cu.in. Cummins six cylinder engine.

The most common type of combustion chamber used in large trucks today is the:

What engine performance measurement is found by using the following formula: Torque x RPM divided by 5252:

As compared to a direct injection chamber, a engine equipped with pre-combustion chambers will:

On a diesel injected engine, if a delivery valve does not seat properly, the engine would:

Technician A says that a fuel injection pump with port and helix system uses a mechanical actuated injector. Technician B says that a distributor type fuel system uses a hydraulically actuated injector. Who is correct?

Technician A says that a Bosch and a Detroit fuel system both use a mechanical type injector. Technician B says that a Bosch and a Detroit fuel system both use a port and helix system. Who is correct?

Which of the following systems would a Cummins engine use to control the fuel injections to the engine?

The primary fuel filter on an engine is on the ___________ side of the fuel pump.

In a distributor type fuel pump, a hydraulically actuated plunger and counter-balancing spring, automatically moves the__________________ back and forth with changing engine speeds, to alter the injections timing advance.

To locate a faulty injector on a Cummins PT injection system you should:

The resistance of a liquid to flowing is called?

There is a delay between the time that fuel is injected into the cylinder and the time that ignition by the hot air takes place. The duration of this delay is expressed as a(n) _____________number:

Success!

Heavy-Duty Mechanic - Trucks & Equipment