Question 1

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 2

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

Accepted Answer

Engine vacuum can be used to operate power brakes, cruise control, and certain components of the air-conditioning system, making all the options correct.

Question 3

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 is responsible for managing the turbo output by controlling the amount of exhaust gas entering the turbine housing. This helps regulate the speed of the turbine and prevents it from spinning too fast, which can cause damage to the turbocharger. The other options, turbine seal assembly, hot wheel, and cold wheel, are not directly involved in managing turbo output.

Question 4

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

Technician A is correct as the intake manifold in carburetor or TBI delivers both air and fuel, and the turbulence caused inside the manifold helps in proper mixing of the air and fuel before being delivered to the cylinders.

Technician B is also correct as in an air only type manifold like in PFI, the length of the runners is very important because it needs to be designed in such a way that it achieves the best performance during a particular range of engine speeds. Therefore, both technicians are correct.

Question 5

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 6

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

The answer of Variable intake manifolds for engines with port...

Question 7

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 is designed into the system to allow the supercharger to idle along when extra power is not needed
D) Superchargers improve horsepower and torque

Accepted Answer

The answer of Which of the following statements concerning superchargers...

Question 8

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 9

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 correct. Technician A's approach helps to break loose any rust or corrosion on the connections, making them easier to remove. Technician B's approach ensures that the new exhaust system will not interfere or rub against any critical components in the vehicle's undercarriage.

Question 10

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

Accepted Answer

An emissions vacuum schematic is typically provided on an under-hood decal for easy reference during maintenance and repairs.

Question 11

Technician A says a vacuum leak results in less air entering the engine, which causes a richer air/fuel mixture. Technician B says a vacuum leak in the system can cause the engine to run poorly. Who is correct?
A) A only
B) B only
C) both A and B
D) neither A nor B

Accepted Answer

A vacuum leak results in more unmetered air entering the engine, causing a leaner air/fuel mixture, not richer. However, a vacuum leak can indeed cause the engine to run poorly, making Technician B correct.

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 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 of the converter to ensure it is functioning properly. An exhaust gas analyzer can be used to measure the emissions of the vehicle before and after the converter to ensure it is reducing harmful emissions.

Question 14

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 15

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 technicians are correct. An intake manifold tuning (IMT) system uses a butterfly valve to divide the plenum into two small chambers at low speeds, and at high engine speeds, the butterfly valve opens to form one large plenum chamber. Similarly, 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.

Question 16

Technician A says a catalytic converter breaks down HC and CO to relatively harmless by-products. Technician B says OBD-II regulations call for a monitoring system that looks at the effectiveness of the converter. 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 catalytic converters are designed to reduce harmful emissions like hydrocarbons (HC) and carbon monoxide (CO) into less harmful substances. Technician B is also correct because OBD-II regulations require vehicles to have systems that monitor the efficiency of the catalytic converter to ensure it is functioning properly.

Question 17

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

The catalytic converter is designed to increase the temperature of the exhaust gases in order to aid in the conversion of harmful pollutants into less harmful ones. The temperature increase of 100 degrees Fahrenheit indicates that the converter is operating properly and doing its job effectively. This temperature increase is expected and is a sign of a functional catalytic converter.

Question 18

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

The given answer CO₂ is not a pollutant from engine exhaust. The pollutants that are changed by the catalytic converter are CO (carbon monoxide), HC (hydrocarbons), and NOx (nitrogen oxides). The option D has a typo and should read NOx instead of NO_X.

Question 19

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 20

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

The answer of Technician A says most turbochargers have their...

Quiz 32: Intake and Exhaust Systems

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

Engine vacuum may be used to operate the ______.

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

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?

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?

Which of the following statements concerning superchargers is NOT correct?

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.

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?

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

Technician A says a vacuum leak results in less air entering the engine, which causes a richer air/fuel mixture. Technician B says a vacuum leak in the system can cause the engine to run poorly. Who is correct?

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

Technician A says a catalytic converter breaks down HC and CO to relatively harmless by-products. Technician B says OBD-II regulations call for a monitoring system that looks at the effectiveness of the converter. Who is correct?

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

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

What is the first step in turbocharger inspection?

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?