Engine performance Chap 11

How quickly can the rocker arms be switched from the low-speed camshaft profile to the high-speed camshaft profile on a Honda equipped with a VTEC system?

100 milliseconds

Ultra-low-sulfur diesel fuel has how much sulfur content?

15 PPM

The normal operating temperature (coolant temperature) of an engine equipped with a 195 degree F thermostat is

195 degree to 215 degree F

Emission controls on what model year vehicles require ultra-low sulfur diesel fuel?

2007

A normally aspirated automobile engine loses about ________ power per 1000 feet of altitude.

3%

How many degrees of CRANKSHAFT rotation are required for a piston to travel from TDC to BDC and return to TDC?

360

What is the commanded pulse width of the camshaft phaser that results in the desired position?

50%

How many degrees of CRANKSHAFT rotation are needed to complete the four stroke combustion cycle?

720

One cylinder of an automotive four-stroke cycle engine completes a cycle every ________.

720 degrees

B-20 biodiesel has how much regular diesel fuel?

80%

E85 means that the fuel is made from ________.

85% ethanol, 15% gasoline

Which valve is used on a factory supercharger to limit boost?

A bypass valve

Low engine operating temperatures will cause all of the following EXCEPT ________

Accumulation of water in oil. Cylinder wall wear. Rust formation. All of these are symptoms of low operating temperatures.

All these are functions of the air intake system

Act as a flame arrester in case of backfire. Silence intake noise. Clean the air.

Which statement is correct? Long intake runners are good for low-RPM torque. Some engines use a variable intake runner design to improve engine efficiency. Short intake runners are good for high-RPM horsepower

All statements are correct

Most manufacturers of vehicles equipped with diesel engines allow what type of biodiesel?

B20

Which type of relief valve is used on a turbocharged engine is noisy (and awesome)?

BOV Dump valve

The weep hole on a water pump is located where?

Between the seal and the bearing

Technician A says that in going to high altitudes, engines produce lower power. Technician B says that most engine control systems can compensate the air-fuel mixture for changes in altitude. Which technician is correct

Both Altitude

Technician A says that the research octane number is higher than the motor octane number. Technician B says that the octane rating posted on fuel pumps is an average of the two ratings. Which technician is correct?

Both Octane

Technician A says that spark knock, ping, and detonation are different names for abnormal combustion. Technician B says that any abnormal combustion raises the temperature and pressure inside the combustion chamber and can cause severe engine damage. Which technician is correct?

Both abnormal combustion

Technician A says that a bleeder valve is located on many engines to allow air to escape when refilling the cooling system. Technician B says that a hose should be attached to the bleeder valve to allow any escaping coolant to be directed to a suitable container. Which technician is correct?

Both bleeder valve

Two technicians are discussing oil leaks. Technician A says that an oil leak can be found using a fluorescent dye in the oil with a black light to check for leaks. Technician B says that a white spray powder can be used to locate oil leaks. Which technician is correct?

Both tech oils leaks

Two technicians are discussing the term "turbo lag." Technician A says that it refers to the delay between when the exhaust leaves the cylinder and when it contacts the turbine blades of the turbocharger. Technician B says that it refers to the delay in boost pressure that occurs when the throttle is first opened. Which technician is correct?

Both techs delay

Technician A says that a cracked exhaust manifold can affect engine operation. Technician B says that a leaking lower intake manifold gasket could cause a vacuum leak. Which technician is correct?

Both techs exhaust manifold

Technician A says that the paper test could detect a burned valve. Technician B says that a grayish white stain could be a coolant leak. Which technician is correct?

Both techs grayish white stain

When testing thermostats, technician A uses a pyrometer and says the engine side of the thermostat should be the hottest spot in the cooling system. Technician B says that incorrect ignition timing may be the cause of engine overheating. Which technician is correct?

Both techs pyrometer

How are most superchargers lubricated?

By an internal oil reservoir

Variable valve timing can be found on which type of engine?

Cam-in-block DOHC SOHC

Winter blend gasoline ________.

Can cause engine driveability problems if used during warm weather Vaporizes more easily than summer blend gasoline Has a higher RVP

Why are the EGR gasses cooled before entering the engine on some engines?

Cool exhaust gas is more effective at controlling NOx emissions.

What sensors are used by the PCM to determine the best position of the camshafts for maximum power and lowest possible exhaust emissions?

Crankshaft position (CKP) Camshaft position (CMP) Engine speed (RPM)

An engine fails to reach normal operating temperature. Which is the most likely fault?

Defective thermostat

The procedure that should be used when refilling an empty cooling system includes ________.

Determine capacity, then fill the cooling system halfway with antifreeze and the rest of the way with water

All of these are correct EXCEPT ________

Engines produce higher horsepower at higher altitude.

Permanent antifreeze is mostly ________.

Ethylene glycol

To reduce oxides of nitrogen (NOx) exhaust emissions, which camshaft is varied?

Exhaust camshaft only

A stuck open thermostat can cause ________.

Failure of a State emission test Lower fuel economy Increased exhaust emissions

What can be used to measure the alcohol content in gasoline?

Graduated cylinder Electronic Tester

All overhead valve engines ________.

Have the overhead valves in the head

Which statement is true regarding cooling systems?

Heat transfer explains how radiators work.

All of the following statements are correct EXCEPT ________ Higher compression engines usually require higher octane fuel. Higher compression engines are more efficient. Higher compression engines are less likely to produce NOx emissions. Higher compression engines can produce more power.

Higher compression engines are less likely to produce NOx emissions.

Vapor lock can occur ________.

If a fuel line is restricted As a result of excessive heat near fuel lines

To avoid problems with the variation of gasoline, all government testing uses ________ as a fuel during testing procedures.

Indolene

To increase engine performance, which camshaft is varied?

Intake camshaft only

Technician A says that some intake manifolds are plastic. Technician B says that some intake manifolds are constructed in two parts or sections: upper and lower. Which technician is correct?

Intake manifolds

Avoid topping off the fuel tank because ________.

It can saturate the charcoal canister

Which is true of biodiesel fuel?

It is more expensive than petrol diesel It can be used in standard diesel systems without modification

A flex-fuel vehicle has enhanced fuel system components that include all of these EXCEPT ________.

Low temperature resistant O-rings

What sensor is usually located between the air cleaner and the throttle body?

MAF

Which alcohol is dangerous (toxic)?

Methanol

Methanol is also called ________.

Methyl alcohol Methyl hydrate Wood alcohol

Which of the following is the most correct statement about the direction of engine rotation?

Most engines rotate clockwise as viewed from the front of the engine.

All of the following statements are correct EXCEPT ________ Most mufflers have a larger outlet than inlet. Most mufflers have a larger inlet than outlet. Resonators resemble small mufflers and are used to further quieten exhaust system noise. Mufflers catch the high pressure air pulses from the exhaust system.

Most mufflers have a larger outlet than inlet.

Which of the following is correct? Increasing air pressure always increases its density. Naturally aspirated engines have more compression than forced induction engines. Naturally aspirated engines require higher octane fuel. Naturally aspirated engines use atmospheric pressure to force air into the combustion chamber.

Naturally aspirated engines use atmospheric pressure to force air into the combustion chamber.

Which of the following is correct? Corrosion forms in the exhaust system in the absence of moisture. One gallon of gasoline produces a gallon of moisture during complete combustion. Water will not harm the exhaust system. A small hole at one seam of a muffler means it is damaged and must be replaced.

One gallon of gasoline produces a gallon of moisture during complete combustion.

Boost pressure is generally measured in ________.

PSI

Which statement is correct? Port fuel injected vehicles mix the fuel and air charge in the intake manifold. With port fuel injection, fuel is injected directly into the combustion chamber. Throttle body injected vehicles do not require heating of the intake air charge.

Port fuel injected vehicles mix the fuel and air charge in the intake manifold.

Liquefied petroleum gas (LPG) is also called ________.

Propane

How is the camshaft actuator controlled?

Pulse width modulated (PWM) signal

Which is true of biodiesel fuel?

Reduces hydrocarbon emissions Reduces particulate matter in emissions Reduces carbon monoxide emissions

What service operation is most important on engines equipped with a turbocharger?

Regular oil changes

Two types of superchargers include ________.

Roots type and centrifugal

Which of these symptoms may be caused by excessive ethanol in the fuel?

Rough idle or stall

All of the following statements are correct EXCEPT ________ Supercharging often removes hot exhaust gasses to lower the cylinder head temperature. Supercharging uses an air pump to force air into the combustion chamber. Supercharging often results in high emissions during deceleration and idle. Supercharging allows for lower compression when the engine is not required to produce high power.

Supercharging often results in high emissions during deceleration and idle.

Technician A says that the crankshaft determines the stroke of an engine. Technician B says that the length of the connecting rod determines the stroke of an engine. Which technician is correct?

Tech A crankshaft

Technician A says that header-type exhaust manifolds produce less back pressure than do most cast-iron exhaust manifolds. Technician B says that only cast-iron exhaust manifolds are used on production vehicles. Which technician is correct?

Tech A less back pressure

Technician A says that changing connecting rod length changes engine stroke. Technician B says that changing connecting rod length changes the position of the piston in the cylinder. Which technician is correct?

Tech B Changes position on the piston

Technician A says that the Helmholtz resonator is used to speed up incoming air into the intake manifold. Technician B says that the Helmholtz resonator is used to quieten intake noise. Which technician is correct?

Tech B Helmholtz

Technician A says that a stuck-open wastegate can cause the engine to burn oil. Technician B says that a clogged PCV system can cause the engine to burn oil. Which technician is correct?

Tech B PCV systems

Technician A says that you must completely drain coolant before replacing the thermostat. Technician B says that a defective thermostat is always the cause of an engine not getting hot enough. Which technician is correct?

Tech B cause of engine not getting hot enough

Technician A says that a typical DOHC V6 engine uses two camshafts. Technician B says that overhead cam engines generally can run at higher rotational speeds than overhead valve engines. Which technician is correct?

Tech B overhead cam engines

Technician A says the stoichiometric ratio for gasoline is about 9.0:1. Technician B says the stoichiometric ratio for ethanol is about 9.0:1. Which technician is correct?

Tech B stoichiometric

If the engine oil is not changed regularly, what is the most likely fault that can occur to an engine equipped with variable valve timing (VVT)?

The filter screens on the actuator control valve become clogged

As the percentage of antifreeze in the coolant increases, ________.

The freeze point decreases (up to a point)

Which statement is true about thermostats?

The temperature marked on the thermostat is a temperature at which the thermostat should start to open.

A heated air intake system is usually necessary for proper cold-engine driveability on ________.

Throttle body fuel injection systems

Why do many port fuel injected engines use long intake runners?

To increase low RPM power

What is the purpose of an intercooler?

To reduce the temperature of the air entering the engine

A rotating force is called ________.

Torque

The following statements are all correct EXCEPT ________

Torque always results in movement

The following statements are all correct EXCEPT ________

Torque always results in movement.

Using ethanol-enhanced or reformulated gasoline can result in reduced fuel economy. T or F

True

An SOHC V8 engine has how many camshafts?

Two

On many variable displacement engines the cylinder deactivation is done by use of a(an) ________.

Two stage hydraulic lifter

Which of the following is the least likely to cause an engine noise?

Vacuum leak

Which of the following is correct? Many exhaust systems are tuned to reduce noise and optimize flow. Exhaust manifolds must be able to slide on the cylinder head slightly as they expand due to high heat. Many exhaust systems have heat shields to protect the spark plugs and wires.

all statements are corrects exhaust

What rating of diesel fuel indicates how well a diesel engine will start?

cetane rating

The intake manifold of a port fuel-injected engine ________.

contains air only

A water pump is a positive displacement-type pump.

false

Horsepower is expressed in units of ________.

foots per pound

Which method of blending ethanol with gasoline is the most accurate?

inline

Most variable camshaft systems use ________ to control camshaft position.

oil pressure

How many rotations of the crankshaft are required to complete each stroke of a four-stroke cycle engine?

one-half

The upper portion of a two part intake manifold is often called the ________.

plenum

Torque is expressed in units of ________.

pound-feet

Which component is NOT needed in a typical overhead cam engine?

pushrod

Used coolant should be ________.

recycled or disposed of properly.

What color is diesel fuel dyed if it is for off-road use only?

red

Adding up to 10% ethanol to gasoline can also increase the fuel's ________.

volitility