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Failure of fuel injection is usually due to trouble in the ().
A . exhaust valves
B . mechanical lubricators
C . cooling water pumps
D . fuel injection pum
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If the diesel engine fuel injection timing is changed to delay the start of injection until the pistons are at top dead center, the engine will()
A . backfire through the air intakes
B . develop less power under load
C . have high firing pressures
D . lift its cylinder relief valve
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As the plunger moves up, the ports are closed and the fuel () and delivered to the injector nozzle at very high pressure.
A . being compressed
B . to be pumped up
C . is pressurized
D . are built u
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Problems with the diesel engine fuel injection pump are usually caused by()
A . improper adjustment
B . contaminated fuel
C . kinked fuel lines
D . excessive engine vibratio
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During the fuel injection period, fuel pressure must exceed cylinder gas pressure to ().
A . ensure penetration and distribution of the fuel in the combustion chamber
B . ensure the needle valve is flushed clean during each injection
C . prevent combustion gas blowback into the open needle valve
D . prevent reflected pressure waves when the needle valve close
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The amount of fuel delivered by a unit injector is controlled by the ()
A . camshaft
B . main spring
C . rack position
D . nozzle orifice size
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Maintaining the close tolerances in diesel fuel pumps and injectors requires the use of().
A . fuel/water separators
B . day tanks
C . injector test stand
D . fuel filter
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When the opening pressure of a diesel fuel injector is greater than that specified by the engine manufacturer,the ()
A . quantity of fuel injected is decreased
B . quantity of fuel injected will always be increased
C . start of injection is advanced
D . duration of injection will always be greater
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The needle valve in the injector () at a pre-set pressure which ensures that the fuel will atomize once it enters the cylinder.
A . will lift
B . will be lifted
C . will close
D . will be closed
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In a diesel engine, when the fuel is injected into the cylinder,()
A . the piston is just coming upward from the bottom dead center
B . the piston has moved about one-fifth of the way up
C . the piston has moved most of the way up and almost reached the TDC
D . the piston has just past the TDC
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If the needle valve in a fuel injection nozzle sticks open ().
A . no fuel will be delivered through the nozzle
B . the nozzle will overheat and crack
C . time of injection will change
D . fuel will leak into the drain line
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Fix the fuel injector into () after repair.
A . the cylinder liner
B . the cylinder cover
C . the cylinder jacket
D . the pisto
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The injection may be delayed, ()the pumps are in good order, if the fuel lines to the injection valves have not been cleared of air.
A . because
B . though
C . since
D . until
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In a common rail engine, the fuel is injected into cylinders()
A . by injection pumps
B . at a time decided by the injection pump timing
C . by a signal opening the magnetic valves
D . at a time decided by the cam directly
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Fuels of different qualities may require advancing or retarding the injection timing, in addition to which if the injection timing is advanced when the engine is running at loads below the (), then a saving in fuel can be achieved.
A . BHP
B . MCR
C . IHP
D . MEP
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The sequence of fuel injection into cylinders is determined by ().
A . the steering
B . the driven gear
C . the turning gear
D . the timing gear
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Air in the fuel lines to the fuel injection nozzles of a diesel will result in ().
A . lower compression pressures
B . overheating without smoking
C . failure to start
D . a run away without load
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The major cause of fuel pump and injection system problems is ()
A . improper adjustments
B . contaminated fuel
C . kinked fuel lines
D . excessive engine vibratio
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The plunger in the fuel injector pump, usually operated by a (), is driven up and down when working.
A . crankshaft
B . camshaft
C . piston rod
D . rack and pinio
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If the plunger or barrel of a fuel injection jerk pump becomes damaged,()
A . only the replacement of the entire pump would be acceptable
B . the injection pump and injection nozzle must be replaced
C . either the barrel or plunger must be replaced
D . the barrel and plunger must be replaced as a unit
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The amount of fuel injection into a diesel engine cylinder by a unit injector, is controlled by()
A . the firing pressure in the cylinder
B . a metering helix inside the pump
C . varying the physical length of the plunger stroke
D . varying the clearance between the injector cam and the injector rocker arm
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Early fuel injection timing is indicated by the cylinder pressure being()
A . above normal with a below normal exhaust temperature
B . above normal with a normal exhaust temperature
C . below normal with a normal exhaust temperature
D . below normal with an above normal exhaust temperature
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To minimize the formation of carbon deposits on fuel injection nozzles, you should ()
A . avoid using liquid-cooled nozzles whenever possible
B . avoid low cooling water temperatures
C . avoid prolonged overloading of the engine
D . make certain the gasket seal between the nozzle and cylinder head is tight
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The fuel injector pump is operated by () which drives the plunger up and down.
A . a separate motor
B . a cam
C . a generator
D . a chai