Question 1

Technician A says a catalytic converter may be tested with a pyrometer. Technician B says a converter may tested using an exhaust gas analyzer. Who is correct?
A)A only
B)B only
C)both A and B
D)neither A nor B

Accepted Answer

Both technicians are correct. A pyrometer can be used to measure the temperature difference across the catalytic converter to assess its efficiency, while an exhaust gas analyzer can measure the levels of specific gases before and after the converter to evaluate its performance.

Question 2

Which of the following statements concerning superchargers is NOT correct?
A)Superchargers must overcome inertia and spin up to speed as the flow of exhaust gas increases
B)Superchargers do not require a waste gate to limit boost
C)A bypass allows the supercharger to idle when extra power is not needed
D)Superchargers improve horsepower and torque

Accepted Answer

Superchargers are mechanically driven by the engine's crankshaft, not by exhaust gases, which is the principle of operation for turbochargers. Therefore, they do not need to overcome inertia and spin up as exhaust flow increases.

Question 3

Before replacing an exhaust system component, Technician A soaks all old connections with a penetrating oil. Technician B checks the old system's routing for critical clearance points. Who is correct?
A)A only
B)B only
C)both A and B
D)neither A nor B

Accepted Answer

Both technicians are following best practices for exhaust system replacement. Technician A is using penetrating oil to ease the disassembly process by loosening rusted or seized connections, which is a common and recommended approach. Technician B is checking the routing of the old exhaust system to ensure that the new system does not interfere with other vehicle components and maintains proper clearance, which is crucial for safety and functionality.

Question 4

A turbocharged engine is running with 10 psi (69 kPa)of turbo boost. At what pressure is air being fed into the engine when the engine is operating at sea level?
A)4.7 psi (32 kPa)
B)10 psi (69 kPa)
C)14.7 psi (101 kPa)
D)24.7 psi (170 kPa)

Accepted Answer

The air is being fed into the engine at a pressure of 24.7 psi (170 kPa) because the turbo boost pressure of 10 psi (69 kPa) is added to the atmospheric pressure at sea level, which is 14.7 psi (101 kPa).

Question 5

Technician A says an intake manifold that delivers both air and fuel (carburetor or TBI)is designed to cause turbulence so that the air and fuel mix while they are being delivered to the cylinders. Technician B says in an air only type manifold (PFI)the length of the runners is designed to achieve the best performance during a particular range of engine speeds. Who is correct?
A)A only
B)B only
C)both A and B
D)neither A nor B

Accepted Answer

Both technicians are correct. Technician A is correct in stating that intake manifolds designed for carburetor or Throttle Body Injection (TBI) systems aim to mix air and fuel efficiently through turbulence. Technician B is correct in stating that for Port Fuel Injection (PFI) systems, the length of the intake runners is optimized for performance at specific engine speed ranges, utilizing the principle of resonance and air column inertia to improve cylinder filling at those speeds.

Question 6

Which of the following is NOT an engine exhaust pollutant that is changed by the catalytic converter? A)CO B)HC C)CO₂ D)NO _X

Accepted Answer

COS (carbon oxysulfide) is not a common engine exhaust pollutant addressed by catalytic converters. Catalytic converters primarily convert CO (carbon monoxide), HC (hydrocarbons), and NOx (nitrogen oxides) into less harmful emissions.

Question 7

Technician A says turbocharging uses the heat energy in the engine's exhaust gases to drive a pump that compresses the intake air. Technician B says supercharging relies on the rotation of the engine to compress the air.
A)A only
B)B only
C)both A and B
D)neither A nor B

Accepted Answer

Both statements are correct. Turbocharging does indeed use exhaust gas to drive a turbine that compresses intake air, increasing the engine's efficiency and power. Supercharging compresses air using a mechanical connection to the engine, typically through a belt, to force more air into the combustion chamber.

Question 8

What is the first step in turbocharger inspection?
A)Check the air cleaner for dirty element
B)Open the turbine housing at both ends
C)Start the engine and listen to the system
D)Remove the ducting from the air cleaner to turbo and examine the area

Accepted Answer

The answer of What is the first step in turbocharger...

Question 9

Technician A says a vacuum leak will cause an engine to run richer than normal. Technician B says a vacuum leak can cause an engine to detonate. Who is correct?
A)A only
B)B only
C)both A and B
D)neither A nor B

Accepted Answer

A vacuum leak introduces additional air into the engine, making the air-fuel mixture leaner, not richer, so Technician A is incorrect. A lean mixture can indeed cause an engine to detonate, making Technician B correct.

Question 10

Variable intake manifolds are being discussed. Technician A says an intake manifold tuning (IMT)system uses a butterfly valve to divide the plenum into two small chambers at low speeds. At high engine speeds, the butterfly valve opens to form one large plenum chamber. Technician B says the intake manifold runner control (IMRC)system changes the path of air between long and short runners or between small-diameter and large-diameter runners according to engine speed. Who is correct?
A)A only
B)B only
C)both A and B
D)neither A nor B

Accepted Answer

Both Technician A and Technician B are correct. Technician A describes the function of an intake manifold tuning (IMT) system, which indeed uses a butterfly valve to alter the plenum chamber size based on engine speed. Technician B accurately describes the intake manifold runner control (IMRC) system, which adjusts the air path between different runner lengths or diameters to optimize engine performance at varying speeds.

Question 11

Which of the following is NOT a characteristic of a turbocharger?
A)It increases engine power by compressing the air that goes into the combustion chambers.
B)It is usually located close to the exhaust manifold.
C)It utilizes an exhaust-driven turbine wheel.
D)It requires a mechanical connection between the engine and the pressurizing pump.

Accepted Answer

Turbochargers use exhaust gases to drive a turbine, which then compresses air into the combustion chamber, increasing power. They do not require a mechanical connection to the engine; this is a characteristic of superchargers, not turbochargers.

Question 12

Technician A says the air filter is designed to prevent engine fires in the event of a backfire. Technician B says the air filter assembly is also designed to help reduce the noise caused by the movement of intake air. Who is correct?
A)A only
B)B only
C)both A and B
D)neither A nor B

Accepted Answer

Both technicians are correct. The air filter does help in preventing engine fires in the event of a backfire by acting as a flame arrestor, and it also helps in reducing the noise caused by the movement of intake air.

Question 13

Technician A says engine vacuum is normally measured in inches of mercury (in. Hg). Technician B says a pressure gauge that is labeled psig will read 14.7 psi at sea level. Who is correct?
A)A only
B)B only
C)both A and B
D)neither A nor B

Accepted Answer

Technician A is correct because engine vacuum is indeed typically measured in inches of mercury (in. Hg). Technician B is incorrect because a gauge labeled psig (pounds per square inch gauge) measures pressure relative to atmospheric pressure and would read 0 psi at sea level, not 14.7 psi.

Question 14

What manages turbo output by controlling the amount of exhaust gas entering the turbine housing?
A)waste gate
B)turbine seal assembly
C)hot wheel
D)cold wheel

Accepted Answer

The waste gate manages turbo output by controlling the amount of exhaust gas that enters the turbine housing, thereby regulating the speed of the turbocharger and preventing it from spinning too fast.

Question 15

Which of the following is NOT a metal used for producing exhaust manifolds?
A)cast iron
B)aluminum
C)heavy-gauge sheet metal
D)stainless steel

Accepted Answer

The answer of Which of the following is NOT a...

Question 16

Variable intake manifolds for engines with port fuel injection are being discussed. Technician A says at low speeds, the air travels through a short or large diameter runner. Technician B says they deliver more power at high speed. Who is correct?
A)A only
B)B only
C)both A and B
D)neither A nor B

Accepted Answer

Technician B is correct. Variable intake manifolds use long runners at low speeds to increase torque and short runners at high speeds to increase power.

Question 17

Engine vacuum may be used to operate the ______.
A)power brakes
B)cruise control
C)air-conditioning system
D)All the answers are correct.

Accepted Answer

Engine vacuum is commonly used to assist in operating power brakes, cruise control systems, and some components of the air-conditioning system, making all the provided options correct.

Question 18

A catalytic converter is being tested with a pyrometer. The outlet temperature is 100 degrees Fahrenheit higher than the inlet temperature. What is indicated?
A)The engine is running hot
B)The engine is running too lean
C)Nothing is happening in the converter
D)The converter is operating properly

Accepted Answer

A properly operating catalytic converter will have a higher outlet temperature than inlet temperature, indicating that the catalyst is actively working to convert harmful emissions into less harmful gases. This temperature difference is a sign of proper operation.

Question 19

Technician A says most turbochargers have their own, self-contained, lubrication system. Technician B says a turbocharger should not be operated at an engine oil pressure lower than 30 psi. Who is correct?
A)A only
B)B only
C)both A and B
D)neither A nor B

Accepted Answer

Turbochargers typically rely on the engine's oil supply for lubrication, not a self-contained system. However, it is important for a turbocharger to have sufficient oil pressure, generally not lower than 30 psi, to ensure proper lubrication and cooling.

Question 20

Technician A says the emission vacuum schematic for the vehicle can only be found in the factory service manual. Technician B says an emissions vacuum schematic is given on a decal under the hood. Who is correct?
A)A only
B)B only
C)both A and B
D)neither A nor B

Accepted Answer

Technician B is correct because emissions vacuum schematics are typically provided on a decal under the hood of the vehicle for easy reference.

Quiz 32: Intake and Exhaust Systems

Technician A says a catalytic converter may be tested with a pyrometer. Technician B says a converter may tested using an exhaust gas analyzer. Who is correct?

Which of the following statements concerning superchargers is NOT correct?

Before replacing an exhaust system component, Technician A soaks all old connections with a penetrating oil. Technician B checks the old system's routing for critical clearance points. Who is correct?

A turbocharged engine is running with 10 psi (69 kPa) of turbo boost. At what pressure is air being fed into the engine when the engine is operating at sea level?

Which of the following is NOT an engine exhaust pollutant that is changed by the catalytic converter?

Technician A says turbocharging uses the heat energy in the engine's exhaust gases to drive a pump that compresses the intake air. Technician B says supercharging relies on the rotation of the engine to compress the air.

What is the first step in turbocharger inspection?

Technician A says a vacuum leak will cause an engine to run richer than normal. Technician B says a vacuum leak can cause an engine to detonate. Who is correct?

Which of the following is NOT a characteristic of a turbocharger?

Technician A says the air filter is designed to prevent engine fires in the event of a backfire. Technician B says the air filter assembly is also designed to help reduce the noise caused by the movement of intake air. Who is correct?

Technician A says engine vacuum is normally measured in inches of mercury (in. Hg) . Technician B says a pressure gauge that is labeled psig will read 14.7 psi at sea level. Who is correct?

What manages turbo output by controlling the amount of exhaust gas entering the turbine housing?

Which of the following is NOT a metal used for producing exhaust manifolds?

Variable intake manifolds for engines with port fuel injection are being discussed. Technician A says at low speeds, the air travels through a short or large diameter runner. Technician B says they deliver more power at high speed. Who is correct?

Engine vacuum may be used to operate the ______.

A catalytic converter is being tested with a pyrometer. The outlet temperature is 100 degrees Fahrenheit higher than the inlet temperature. What is indicated?

Technician A says most turbochargers have their own, self-contained, lubrication system. Technician B says a turbocharger should not be operated at an engine oil pressure lower than 30 psi. Who is correct?

Technician A says the emission vacuum schematic for the vehicle can only be found in the factory service manual. Technician B says an emissions vacuum schematic is given on a decal under the hood. Who is correct?