auto service exam - grafton school district · name the strokes of the 4 cycle: • intake (down...

Auto Service Exam

General Shop Information, Tools, & Safety

“Flat Rate” refers to a system of billing for repairs as well as a way of earning, based on the time it should take to do a job.

• True

“Drive Size” of either a ratchet or a socket refers to the size of the square lug & square hole where they snap together.

• True

A service writer or a service advisor is the customerto technician liaison in an automotive dealership.

• True

A torxtip and a phillipshead screwdriver both have the same

shape and can be used interchangeably.

• False

Precision tools such as micrometers, dial calipers, and

dial indicators can make measurements to the nearest

.001 inch or .01 mm.

• True

The acronym NIASE stands for: National Institute of:

• Automotive Service Excellence

Why should engine oil & filter be changed at regular intervals between 3,0005,000 miles?

• To extend the service life of the engine by maintaining proper and clean lubrication

What are the advantages of using airpowered, impact

wrenches?

• Impact wrenches speed up work, can increase production, and are used for their tremendous twisting force

Why should headlights be properly aimed?

• Provide the driver with a good view of the road after daylight hours

• Prevent oncoming traffic from being blinded by improper aim

• Allow a view of the centerline as well as the sideoftheroad white line

List the 4 basic divisions of a vehicle as discussed this semester: • Body • Chassis • Drive Train • Engine

Name 4 fluids that can be checked or serviced from under the hood: • Engine Oil • Engine Coolant • Brake & Clutch Fluid • Automatic Transmission Fluid • Battery Electrolyte • Power Steering Fluid • Windshield Washer Fluid

Explain either the DRL or the CHMSL/CHMBL lighting system: • DRL are Daytime Running Lights • Headlight operate at reduced voltage all the while the vehicle is running & in gear

• CHMSL are the Center High Mount Stop Lights

• Located higher than the regular brake lamps to provide a better view in traffic

Diagnostic machine used to measure engine emissions at the tailpipe before and after a tuneup

• Hydrometer • Impact Sockets • Torque Wrench • Box Wrench • Tachometer

• Open End Wrench • Combination Wrench • Digital Multimeter • 5Gas Infrared Analyzer • Micrometer & Dial Caliper

These shallow or deep, square drive tools are overbuilt to be used with either electric or air

powered wrenches • Hydrometer • Impact Sockets • Torque Wrench • Box Wrench • Tachometer


Used to measure specific gravity of either battery electrolyte or ethylene glycol engine coolant



Handheld wrench with two closed ends



Used to measure engine crankshaft speed and express it in rpm’s



Used to make precise measurements to the nearest .001”



Handheld wrench with one open end and one closed end



Electrical test equipment capable of measuring voltage, amperage, resistance, temperature, rpm, capacitance, and continuity



Handheld wrench not intended for initial loosening or final tightening of fasteners



This wrench is used when exact tightness in either footpounds, inchpounds, or newtonmeters is

desired • Hydrometer • Impact Sockets • Torque Wrench • Box Wrench • Tachometer


Auto Service Exam

Theory of Engine Operation & Systems

The 4 stroke cycle, reciprocating piston engine is the most

common automobile engine in use today.

• True

Octane rating is an indication of how well engine oil resists

burning.

• False

The camshaft can be connected to the crankshaft by either

gears, sprockets & chains, or a cogged belt.

• True

The piston of an engine has some skirt length to prevent it from tipping sideways as it reciprocates in the cylinder.

• True

Of the Lhead, Ihead, Fhead, & Thead valve arrangements,

the Ihead (OHV) valve arrangement is most common.

• True

Name the strokes of the 4 cycle: • Intake (down stroke with intake valve open) • Compression (upstroke with both valves closed) • Power (forceful down stroke with fuel burning) • Exhaust (upstroke with exhaust valve open)

• 180º crankshaft rotation for each stroke (720º Total) • 90º camshaft rotation for each stroke (360º Total)

Name 2 engine cylinder arrangements:

• InLine • InLine Slant • VShape • Flat or Opposed (Boxer)

Name the 3 parts of the engine fire triangle:

• Air • Fuel • Heat of Compression & Spark

From what nonrenewable resource is gasoline refined?

• Petroleum or Crude Oil

Define “engine firing order”

• The sequence in which the air & fuel mixture is ignited in the cylinders

Define “engine displacement”

• Cylinder Volume • B x B x S x .785

• Total Cylinder Volume • B x B x S x .785 x # of Cylinders

List 4 ways of classifying engines:

• Horsepower, Torque, Displacement • By Systems like Cooling & Ignition & Fuel • Year, Make, Mounting & Location • # of Valves, # of Camshafts, # of Cylinders • Cylinder Arrangement, Valve Arrangement • Camshaft Drives, Valve Train, Comb Chamber • Turbo or Supercharged, Cycle of Operation

What is the purpose of the piston rings & what test can tell

their condition? • Piston Rings seal the piston to the cylinder walls preventing blowby into the crankcase

• The compression test tells their condition • Ring end gap measures their wear

Engine component which distributes the incoming air to the cylinders and in an EFI engine, may contain the fuel injectors

• Compression Ratio • Vacuum • Exhaust Manifold • Rotary Motion • Valve Train

• Intake Manifold • Reciprocating Motion • Atomization • Harmonic Balancer • Engine Systems

Mechanical, Electrical Fuel, Exhaust, Emission Control,

Lubrication, Ignition, Cooling, Electronic Engine Management • Compression Ratio • Vacuum • Exhaust Manifold • Rotary Motion • Valve Train


Engine component, often called the vibration damper, has the

purpose of smoothing or balancing out power impulses



The pressure, less than atmospheric, caused by the pistons

moving downward on intake strokes



Name for all of the parts associated with operation of the engine

poppet valves



circular motion



Comparison of cylinder volume with the piston at BDC to that of the combustion chamber volume

with the piston at TDC • Compression Ratio • Vacuum • Exhaust Manifold • Rotary Motion • Valve Train


back and forth or up and down motion



Engine component which collects spent combustion gases and delivers them to the muffler



Action of breaking fuel up into particles and mixing it with air to form a burnable mixture, done by

the carburetor or injectors • Compression Ratio • Vacuum • Exhaust Manifold • Rotary Motion • Valve Train


Auto Service Exam

Cooling, Lubrication, & Air Conditioning

A proper mixture of antifreeze & water will protect a cooling system against freezing and

also raise the coolant boil point.

• True

Air conditioning systems can cool as well as dehumidify the passenger compartment air.

• True

The best API oil rating for gasoline engine oils is now

“SA”.

• False, it’s SM

SAE 5w30 and SAE 10w30 are often recommended oil

viscosities for modern day engines.

• True

Heat transfer is always from an area or an object with more heat to an area or an object

with less heat.

• True

What is the recommended mixture (%’s) of antifreeze and water for a cooling system?

• 50% water & 50% engine coolant • Either ethylene glycol or propylene glycol

List the 4 basic parts of an automotive air conditioning

system: • Compressor • Condenser • Expansion Valve or Expansion Tube • Evaporator

Define “viscosity”:

• Resistance of a liquid, such as engine oil to flow

• Higher Viscosity #’s = thicker oil • Lower Viscosity #’s = thinner oil

Where is the automatic transmission cooler is located: • In the outlet tank of the radiator

What part controls the coolant exchange between the radiator & the reservoir in a closed

cooling system?

• The Radiator Pressure Cap

What is the purpose of an oil filter antidrain back valve?

• Keeps oil in the filter after the engine is shut off so that a “dry start” is prevented

What is the “short name” of the replacement for R12?

& why has it been mandated by federal law?

• R134a • Because R12 causes ozone depletion which leads to increases in skin cancer

Define heat conduction, convection, & radiation

• Conduction is heat transfer through physical contact

• Convection is heat transfer through air movement

• Radiation is heat transfer through light waves

List 4 jobs that oil performs:

• Lubricates • Cleans • Cools • Seals

Passages in the engine block through which oil circulates on its way to lubricate internal engine

parts • Water Jackets • Oil Pump • Oil Galleries • Thermostat • Radiator

• PCV Valve • 1 British Thermal Unit • ReceiverDrier or Accumulator • Heater Core • Oil Filter ByPass Valve

Small heat exchanger used to warm the passenger compartment

• Water Jackets • Oil Pump • Oil Galleries • Thermostat • Radiator


Allows dirty oil to circulate past a clogged oil filter to prevent lack of

lubrication



Device used to redirect blowby gases back into the incoming air stream with the goal of preventing

crankcase oil dilution • Water Jackets • Oil Pump • Oil Galleries • Thermostat • Radiator


The main heat exchanger in a liquid cooling system



Impeller used to circulate coolant through the liquid cooling system

• Water Pump • Oil Pump • Oil Galleries • Thermostat • Radiator


Passages in the engine block and cylinder heads through which coolant circulates to cool the

engine • Water Jackets • Oil Pump • Oil Galleries • Thermostat • Radiator


Wax pellet, temperature sensitive device used to control coolant flow out of the engine block on its way

to the radiator • Water Jackets • Oil Pump • Oil Galleries • Thermostat • Radiator


The quantity of heat needed to raise the temperature of one pound of water one degree

Fahrenheit • Water Jackets • Oil Pump • Oil Galleries • Thermostat • Radiator


Unit in an A.C. system which operates as both a storage device for refrigerant and contains a desiccant to absorb moisture



Auto Service Exam

Electrical Theory, Charging, Starting, Ignition, and Accessory Systems

Battery electrolyte is acidic & corrosive and worse yet, the hydrogen gas given off from it

can be very explosive.

• True

Resistor spark plugs and suppression (TVRS) plug wires contain extra resistance in an effort to eliminate radio static

(RFI).

• True

Electricity can be produced by moving magnetic fields through coiled conductors.

• True

As engine load changes, spark timing must also change. This can easily be done by the PCM.

• True

On distributorless ignition systems, one coil fires two spark plugs at a time one burns air & fuel, the other is wasted on the exhaust stroke.

• True

What 3 things make up a basic circuit?

• Consumer or Load (has the resistance) • Source (has the voltage) • Conductive Path (carries the amperage)

Name the 3 basic types of circuits:

• Series (links of a chain) • Parallel (ladder) • SeriesParallel (combination of the two)

What is the name for the comparison of the density of battery electrolyte to water?

• Specific Gravity • Should be 1.280 for a fully charged battery • Would be 1.000 for a totally dead battery

Define “Ohm’s Law”:

• Mathematical relationship between volts, amps, and ohms in every circuit

Which electrode is the one to bend to adjust spark plug gap?

• Side or Ground Electrode

Which spark plug has a hotter heat range?

• Long nose has a long cooling path and is a hotter running plug

• Short nose has a shorter cooling path and is a cooler running plug

What makes up battery electrolyte?

• 36% sulfuric acid H2SO4

• 64% water H2O

Name two devices to protect circuit components against

amperage overloads: • Fuses • Fusible Links • Circuit Breakers

What side of electrical circuits do the body, frame & engine block

form?

• The Ground Side

What tool is used to check spark timing on distributor

ignition systems?

• Timing Light

Compare & Contrast the Primary & Secondary

Ignition Circuits • Primary is low voltage

Contains ignition module or PCM • Secondary is high voltage

Contains Spark Plugs, Plug Wires, etc.

Resistance to electricity flow

• Cold Cranking Amps • Alternator • Ignition Coil • Reserve Capacity • Ohms

• Voltage Regulator • Starter Drive • Amperage • Flasher • Voltage

Intensity or rate of electron flow also known as current flow



Electromotive force



How large of a load a battery can sustain for 30 seconds at zero

degrees Fahrenheit



Device that recharges the battery and supplies electricity to all systems while the engine is

running • Cold Cranking Amps • Alternator • Ignition Coil • Reserve Capacity • Ohms


Length of time that a battery can deliver current of 20 amps without being charged and without falling

below 9.6 volts • Cold Cranking Amps • Alternator • Ignition Coil • Reserve Capacity • Ohms


Device that takes in 12 primary volts and transforms it to the

kilovolts needed to fire the spark plugs



Cycling circuit breaker used to blink the turn signals and hazard

lamps



Component that has a gear to connect the starter armature to

the flywheel or flex plate ring gear during the cranking process



Controls the voltage output of the alternator keeping it at about 14.2

with the vehicle running



Auto Service Exam

Fuel Systems, Electronic Engine Controls, and Emission Control Systems

Sensors are PCM inputs, but fuel injectors, ignition coils & emission control solenoids are outputs controlled by the PCM

• True

If air coming into an engine can be kept at a temperature of 300 degrees, emissions,

performance & mpg will be optimum.

• False!!

Catalytic converters are capable of lowering all three of the major pollutants HC, CO,

and NOx.

• True

Carburetors (carbasaurus☺) are air & fuel mixing devices that used pressure differences & mechanical components to

meter & atomize fuel.

• True

“Ontime” of the fuel injectors is also known as “pulse width” and is controlled by the PCM

to adjust fuel trim.

• True

Name 2 exhaust system parts:

• Exhaust Manifold • Crossover Pipe • Catalytic Converter • Muffler • Tailpipe • Hangers & Clamps

What steps should be taken to start a “flooded” engine & why

does this work? • Placing the throttle in the WOT position and cranking the engine “unfloods” the engine.

• It signals the PCM to enter “clear flood mode” where the injectors are not pulsed.

Name two devices used to raise engine volumetric efficiency:

• Turbochargersexhaust driven • Superchargersbelt driven

Name 3 PCM/EEC sensors:

• TPS, ECT, IAT • CKP, CMP, VSS • P/N, BPP, & PS Switches • MAP, MAF, BARO • HO2S, upstream & downstream

Cold engines, ignoring inactive HO2S, following

preprogrammed instructions are in:

• Open Loop

Warm engines, with active HO2S , that are constantly

adjusting A/F & timing are in:

• Closed Loop

Engines with missing or very confusing input data cause the

PCM to enter this mode:

• Limpin Mode or FailSafe Mode

Emission Control Systems

• PCV takes blowby out of the crankcase & reburns it

• EVAP has a charcoal canister & sealed fuel tank to capture HC vapors

• EGR puts exhaust in with fresh A/F to cool the burn

Emission Control Systems

• CAT chemical reaction in the exhaust system at over 1000 Fº

• AIR injects oxidizing secondary fresh air into the exhaust manifold

• TAC warms incoming air to promote better burning

Single point electronic fuel injection

• Catalyst • Carbon Monoxide • Oxides of Nitrogen • Charcoal or Carbon • Hydrocarbons

• Mechanical Fuel Pump • Stoichiometric • Electric Fuel Pump • Sequential EFI • Throttle Body EFI

Pollutant formed by burning fuel at high pressures and

temperatures over 2500 degrees Fahrenheit



Platinum, Palladium,Rhodium

• Catalysts • Carbon Monoxide • Oxides of Nitrogen • Charcoal or Carbon • Hydrocarbons


The material used in evaporative canisters to capture/absorb fuel

vapors from the fuel tank



The most efficient type of multi port fuel injection system because it pulses injectors in the firing

order of the engine • Catalyst • Carbon Monoxide • Oxides of Nitrogen • Charcoal or Carbon • Hydrocarbons


Type of fuel pump used on EFI systems usually located inside the

fuel tank



Pollutant formed by burning fuel with insufficient amounts of oxygen poison and deadly



Type of fuel pump used on carbureted fuel systems driven by the camshaft and fastened to the

engine block • Catalyst • Carbon Monoxide • Oxides of Nitrogen • Charcoal or Carbon • Hydrocarbons


A word for the theoretically perfect air/fuel ratio which will

result in exhaust capable of being treated by the catalytic converter • Catalyst • Carbon Monoxide • Oxides of Nitrogen • Charcoal or Carbon • Hydrocarbons


Pollutant formed by unburned fuel usually due to a misfire in the engine or by evaporation of fuel



Auto Service Exam

Tires, Wheels, Brakes, Steering & Suspension

A torn or leaking CVjoint boot on a FWD half shaft should be replaced as soon as possible.

• True

Power steering fluid & automatic transmission fluid can be safely substituted for

DOT3 brake fluid in the master cylinder.

• False

The proper tire inflation specs for every tire are conveniently located on each tire’s sidewall.

• False

Asbestos, a heat resistant friction material used in some older brakes and clutches, is a

carcinogen (cancer causing material).

• True

The Uniform Tire Quality Grading System rates the tread wear, traction and temperature resistance of tires. (the 3 T’s)

• True

Define & give the cause of “brake fade”

• Inefficient braking due to overheated linings • Pedal feels firm, but loss of friction occurs

What is the advantage/purpose of “power brakes”?

• Power assisted brakes use either engine vacuum or power steering pressure to make pedal application easier for the driver

What is the advantage of “ABS”?

• Antilock brake systems result in safer stopping by preventing wheel lockup and skidding during braking.

Why are diagonally split & frontrear split hydraulic

systems desirable? • In the event of a brake hydraulic leak, only half of the system fails.

• The remaining two wheels may be able to brake and steer

Name 2 advantages of proper tire inflation:

• Proper inflation extends tire life, is safer, handles better, and promotes even wear on the tires.

What are the 2 basic designs of service brakes?

• Disc • Drum

Parking Brake & Service Brakes are operated:

• Parking brakes mechanically operate the rear brakes only by using cables & levers

• Service brakes hydraulically operate all four corners using a contained fluid

Describe the tire with the size: P 225 / 50 Z R 15

• Passenger car tire • 225 millimeters wide • 50% profile or aspect ratio • Z speed rating • Radial ply design • 15” rim diameter

System that uses the antilock brake components to prevent wheel spin on acceleration

• Wheel Shimmy • Differential • Transaxle • Wheel Tramp • Toe

• Shocks & Struts • Automatic Traction Control • Vulcanization • Camber • Bleeding

Suspension components responsible for limiting up and down movement of springs



Drive train component which allows one wheel to turn slower and one faster during cornering



Action of a tire & wheel shaking back & forth across the road’s surface because of a dynamic

imbalance problem • Wheel Shimmy • Differential • Transaxle • Wheel Tramp • Toe


The inward or outward pointing of the tire as it rolls down the road too much results in saw tooth or

feather edge tire wear • Wheel Shimmy • Differential • Transaxle • Wheel Tramp • Toe


Drive train component made up of a combination of a transmission

and a differential



During tire manufacturing, the action of fusing belts and plies together with heat and pressure



The process of removal of air from a hydraulic brake system or from

a hydraulic clutch system



The inward or outward tilt of the tires at the top too much results in either inside or outside tire tread

wear • Wheel Shimmy • Differential • Transaxle • Wheel Tramp • Toe


Action of a tire & wheel jumping up and down as they revolve because of a static imbalance

problem • Wheel Shimmy • Differential • Transaxle • Wheel Tramp • Toe


auto service exam - grafton school district · name the strokes of the 4 cycle: • intake (down...

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