1. Valves.
   A carburetor.
2. A catalytic converter.
   Fuel filter.

Because the injector atomizes fuel into the air stream, it does not require the suction of the carburetor to draw the fuel into it. However, fuel filters that clean impurities from the fuel, valves that allow fuel into the engine, and catalytic converters that reduce air pollution are all still necessary components.

1. Intake, exhaust, compression, and power.
   Intake, compression, power, and exhaust.
2. Intake, power, compression, and exhaust.
   Power, compression, intake, and exhaust.

Intake is the first downward stroke that brings the fuel-air mixture into the chamber. The second stroke moves upward, compressing the mixture. At that point, a spark ignites the mixture and drives the piston downward in the power stroke. The final stroke moves upward and expels the exhaust from the chamber.

1. It changes harmful gasses into less harmful gasses.
   It mutes the sound of the engine.
2. It converts gear torque into wheel torque on Cadillac brand vehicles.
   It is used by California pollution stations to test engine emissions.

The catalytic converter contains a catalyst to interact with engine exhaust. This reaction changes the harmful gasses created during combustion into less harmful ones.

1. The gasoline engine is a two-stroke engine, and the Diesel is a four-stroke.
   The gasoline engine uses a spark plug, and the Diesel uses a glow plug.
2. The gasoline engine pistons are arranged in a V-shape, and the Diesel pistons point outward in a circle.
   The gasoline engine uses cooking oil to power it, and the Diesel can only use Diesel fuel.

Diesel engines use compression heat to ignite the fuel instead of using an actual spark like gasoline engines. Diesel engines need a heating element, or glow plug, to help start the process on a cold day.

1. Connects the engine to the axle.
   Connects the piston head to the crankshaft.
2. Connects the engine to the transmission.
   Connects the piston head to the camshaft.

The piston head connects to the crankshaft by the connecting rod. The purpose of the rod is to convert the up-and-down motion of the piston into the rotating motion of the crankshaft.

1. The engine is on fire.
   The engine is clean.
2. The engine head block is cracked or warped, and the head gasket has failed.
   The air conditioning system is leaking into the exhaust.

A thick cloud of white smoke indicates that radiator fluid is leaking into the exhaust. The only way for this to happen is if either the head gasket or engine block is damaged.

1. 2.
   3.
2. 4.
   6.

A four-stroke engine must have at least two valves. Therefore, two valves are "standard." Three or more valves increase the efficiency of the engine and give it the “multi-valve” designation.

1. The carburetor.
   The alternator.
2. The crankshaft.
   The solenoid starter.

The solenoid starter cranks the engine when the key is turned. Not only was cranking a car by hand difficult, but it was also dangerous.

1. T, U, and V.
   Flat, star, and delta.
2. I (or straight), V, and W.
   V, W, and X.

The I-engine is an inline or straight engine. A variation of this would be the flat (boxer or horizontal) engine. The V-engine has the pistons angled out, and the W is a combination of the I and V.

1. The crankshaft is leaking.
   The engine block has a hole in it.
2. The valves or piston rings are leaking.
   The camshaft is leaking.

If oil coats the spark plug, it is usually because the piston rings or valves are leaking. This situation can cause the engine to misfire or only spark weakly.

1. The air conditioning needs Freon.
   It is too hot outside.
2. The oil pump has failed.
   The thermostat is bad.

When a car is overheating, the most likely cause is a bad thermostat out of all the options offered. Another reason a car engine might overheat is if there is an internal or external leak. The best thing to do with an overheating engine is to turn the engine off immediately because permanent damage can occur.

1. Increase the amount of power from a two-valve engine.
   They can operate at higher RPMs.
2. The air exchange is better.
   Lower manufacturing cost.

The more valves an engine has, the more it increases the area through which air, fuel, and exhaust travels. It improves the air-exchange efficiency and allows the engine to create more power and operate at higher RPMs. However, it increases the manufacturing cost and can also consume more oil.

1. It improves fuel efficiency.
   It is designed to reduce vibrations.
2. It ensures power flows evenly.
   It maintains engine balance.

Firing order has no effect on fuel efficiency. It is essential for maintaining balance and reducing engine vibration. Proper firing also allows the power output of an engine to flow evenly.

1. It tightens bolts to a specific pressure.
   It is used to tighten or loosen "stuck" bolts.
2. It allows you to remove bolts that are in hard-to-reach places.
   It is used to compress springs.

Torque wrenches are designed to tighten bolts to a specific pressure. Beam style torque wrenches are less reliable than the dial or digital ones. A torque wrench should never be used to loosen a bolt—break bars are designed for that task.

1. With the car off, you should immediately add more water to the radiator
   You need to turn on the air conditioner to make it cooler.
2. You need to turn the car off as soon as possible; wait until it has cooled down before checking it.
   With the car running, you should immediately add more water to the radiator.

Pulling the cap off the radiator when the engine is hot (whether it is running or not) can cause severe burns. The air conditioning may cool the inside of the car, but it will make the engine run hotter and cause more damage. As soon as you shut an overheating car off, it will begin to cool down. You should wait until it is completely cool before attempting to service it.

1. The rocker arm.
   The gudgeon pin.
2. The rod lobe.
   The flywheel.

The gudgeon pin allows the connecting rod to pivot around it in a ratcheting fashion. If the connecting rod does not move freely, it is usually due to rust on the pin.

1. They rock back and forth, so they are less likely to get jammed.
   They are compact.
2. They have almost zero leakage.
   They are cost-saving.

They have almost no leakage. Poppet valves work when cams press against the valve stem and compress the spring. Although their response times are consistent, desmodromic valves are sometimes used in engines that will run at high speeds because of valve float.

1. To maintain a steady engine speed.
   To start the engine.
2. To absorb the engine sound.
   To change transmission gears.

The flywheel is a heavy disk that spins and stores rotational energy. Because the power stroke of the piston is the only one providing energy to the system, the flywheel allows speeds to remain constant and smooth, even during the other three strokes.

1. Converting DC to AC power.
   Electromagnetic principles.
2. Converting chemical energy into mechanical energy.
   Nuclear power principles.

The starter is a coil of wires that uses electromagnetic principles to start the engine when a current passes through it. It spins the drive pinion, which then moves the flywheel to start the engine.

1. 1-2-3-4.
   1-3-2-4
2. 1-3-4-2.
   1-4-2-3.

Although technically any firing order could be designed into the engine, 1-3-4-2 is the standard. Another acceptable but less frequently used order is 1-2-4-3.

1. The piston.
   The camshaft.
2. The crankshaft.
   The axle.

The camshaft operates the valves with protruding lobes. The lobes press different valves open as they rotate.

1. The spark plug gap is set wrong.
   The piston rings are worn.
2. The head gasket is cracked.
   The timing is off.

Blue smoke indicates oil is burning in the combustion chamber. Worn piston rings or worn valve seals could cause this problem.

1. The distributor cap and rotor.
   The spark plugs.
2. The computer and coils.
   A and C.

At one time, cars only used a distributor spinning a rotor to create an electrical current that would flow through the leads to the right spark plug and fire each cylinder in the correct order. However, many modern cars use a more direct system where the computer fires each coil in the correct order.

1. It runs on water.
   It is made out of plastic.
2. It doesn’t have valves.
   It doesn't use pistons.

The center of a Wankel engine contains an internal elliptical rotor instead of reciprocating pistons. Because of its simpler design, it tends to be lighter than piston engines with similar power output.

1. Toyota Mirai.
   BMW i3.
2. Honda Civic.
   Tesla Model S.

Although Honda has experimented with hybrids, its Civic remains powered by a gasoline engine (or hybrid) instead of being fully electric. The Honda Fit EV is the company's pure electric model.

1. It is used to expand piston rings to fit over the piston head.
   It makes it easier to place o-rings.
2. It is for compressing piston rings.
   It is an air compressor used to clean small places.

A ring compressor fits around the piston rings and compresses them so that the piston will fit into the cylinder. There are adjustable and fixed models, each with benefits and drawbacks.

1. In the engine block over the crankshaft.
   Outside the engine block under the bottom of the pistons.
2. Inside the engine block under the crankshaft.
   In front of the engine.

The abbreviation OHV stands for OverHead Valve. It is used to describe a camshaft located directly over the crankshaft in the engine block (as opposed to being over the valves).

1. To inject fuel into the oil.
   To atomize fuel.
2. To purify the fuel.
   To eject used fuel from the combustion chamber.

Fuel injectors atomize fuel into a spray and inject it either into the air stream or directly into the combustion chamber. It is cheaper to use for controlling emissions than the complex carburetors required to do the same job.

1. To ensure proper lubrication.
   To ensure smooth operation.
2. To ensure a tight seal.
   To ensure force is transferred correctly.

Honing is a process of putting small cross-hatches in the metal, which helps it retain oil across its surface. It cannot be too rough, or it will cause excess wear.

1. Gasoline engines have a lower power-to-weight ratio than Diesel engines.
   Gasoline engines produce more carbon monoxide and are less efficient.
2. Gasoline engines are louder than Diesel engines.
   Gasoline engines are more expensive to buy.

Because Diesel engines use compression heat to help create the explosion, they are more efficient and produce less carbon monoxide than gasoline engines. Diesel engines are louder, more expensive, and have a higher power-to-weight ratio.

1. Sprocket cleaner.
   Straight-edge.
2. Calipers.
   Taps.

Thread cleaning taps clean threaded holes to keep debris out of the engine and torque measurements correct. Thread-cutting taps are sometimes used for this purpose, but they can damage the threads if they are not used correctly.

1. It closes.
   It turns on the radiator.
2. It opens.
   It turns on the check engine light.

As the temperature of the engine rises, the thermostat opens, allowing coolant from the radiator to flow more freely into the engine and cool it. The thermostat is made out of metal that expands at the necessary temperatures.

1. Differential Oil Hardware Cylinder.
   Double Overhead Cam.
2. Digital Optimal Horsepower Control.
   Direct Open Hydraulic Catalyst.

When the camshaft is over the valves, it is called an OverHead Cam. When there are two camshafts, one for intake and one for exhaust, it is called a double camshaft. When a camshaft is over the valves, it is considered an overhead camshaft or cam. DOHC is a double overhead camshaft.

1. The crankshaft.
   The cylinder head.
2. The oil pump.
   The piston.

A harmonic balancer tool prevents damage to the crankshaft when pulling the crankshaft out or installing it. It enables you to safely remove and install the harmonic balancer that connects the engine to the drive belts, as well as reducing vibration.

1. Moving the muffler closer to the engine.
   Installing afterburners.
2. Installing headers (extractor manifold).
   Lengthening the exhaust pipe.

Installing headers separates the gas flow from each cylinder, to keep them from interfering with each other. It also maintains the ideal speed of the exhaust and allows cylinders to assist each other.