Fuel System System and Adjusting Flashcards
A properly tuned engine results in?
Lowest possible exhaust emissions
Most efficient engine operation
Maintains rated power output
Reliable engine operation and maximum service life
A tune up can involve what?
Valve and injector adjustments, governor adjustments, engine brake adjustments, injection pump timing checks, Injection nozzle testing
The interval for a tune-up is affected by operating conditions like?
Type of engine load (continuous, intermittent)
Application (on road, off road, stationary)
Excessive valve clearance causes what?
Delayed valve timing and reduced valve openings
A malfunctioning fuel injector can cause what?
Hard starting, Rough idle, Low power, White smoke, Black smoke, Combustion knock
Most hydraulic fuel injectors can be bench tested for?
External leakage, Nozzle opening pressure, Spray pattern, Nozzle chatter, Needle seat to face leakage, Back leakage
To ensure smooth engine operation, the maximum variation in needle valve opening pressure between injectors must be?
Less then 50 PSI
In order to confirm a proper spray pattern, you must know the?
Number of spray holes
Angle at which the holes discharge from the nozzle
To check for needle seat leakage, fuel pressure must be maintained at?
150-200 PSI lower than opening pressure
A dynamometer does what?
Absorbs and measures the power output of an engine
All dynamometers have what three basic components?
A power absorption unit
A load control
A torque measuring device
What are the 3 types of dynamometers?
Engine flywheel
Rear wheel
Power takeoff
Horsepower is equal to what?
Torque x RPM divided by 5252
How do most engine manufacturers rate the fuel economy?
Brake specific fuel consumption (BSFC)
Naturally aspirated engine have a power loss of what for every ____ feet in elevation gain?
3% for every 1000 feet
What are 3 conditions for which an engine would need a tune up?
Whenever the mechanism has been disturbed for repairs
Poor engine operation
Part of scheduled maintenance
What condition must the engine be in when you perform adjustments on the governor?
Warmed up to operating temperature
Define opacity
the degree to which the exhaust smoke blocks light
What causes blue exhaust smoke?
engine burning oil
What causes black exhaust smoke?
lack of air for metered amount of fuel’
to much fuel
plugged air filter
What causes white exhaust smoke?
incorrect injection timing
poor atomization
unburned fuel due to lack of heat
coolant being burned during combustion
