chapter 73 ENGINE

All of the following conditions lead to a black colored exhaust EXCEPT:

A blown head gasket.

__________ charcoal means the charcoal is porous and has a large surface area that can absorb and store large quantities of fuel vapor.

Activated

The ________ of a secondary air injection system pumps air into the exhaust stream and assists the operation of catalytic converter.

Air pump

The EGR valve does not operate at idle because there is only a small amount of air-fuel mixture being burned, so the combustion temperature is __________ 2,500° F (1,371° C).

Approximately

A white colored exhaust can be caused due to a(n) ________.

Blown head gasket

Technician A says that a gas analyzer needs to warm up for at least 10 minutes. Technician B says that a gas analyzer must be zeroed before installing the probe in a vehicle's exhaust. Who is correct?

Both

Technician A says that any vehicle produced after 1996 must monitor the efficiency of the catalytic converter. Technician B says that catalyst monitoring is accomplished with multiple oxygen sensors. Who is correct?

Both

Technician A says that catalytic converters are a post-combustion control device that perform a final cleanup of tailpipe emissions. Technician B says that catalytic converters create heat as they burn off harmful gasses before leaving the exhaust system. Who is correct?

Both

Technician A says that some manufacturers use VVT rather than EGR systems to control oxides of nitrogen. Technician B says that holding the exhaust valves open during the intake stroke will allow for some exhaust gases to be pulled into the engine, acting as an internal EGR system. Who is correct?

Both

Technician A says that some states require emissions testing with only a gas analyzer. Technician B says that some states require emissions testing with an exhaust analyzer and chassis dynamometer. Who is correct?

Both

Technician A says that the PCV system removes blowby gases from the crankcase in a manner that is not harmful to the environment. Technician B says that the PCV system prevents the buildup of crankcase pressure. Who is correct?

Both

Technician A says that the two-way catalytic convertor was the first type of catalytic convertor designed. Technician B says that it converts hydrocarbons and carbon monoxide to carbon dioxide and water. Who is correct?

Both

A vehicle with an EVAP-related concern is diagnosed. Technician A says that a scan tool can be used to pull any diagnostic codes. Technician B says that if there are no diagnostic codes, the scan tool can be used to view the live sensor and actuator data. Who is correct?

Both Technician A and Technician B

Technician A says that black exhaust indicates a very rich-running engine. Technician B says that white exhaust can indicate coolant in the exhaust. Who is correct?

Both Technician A and Technician B

Technician A says that the gas cap in an EVAP system is prone to leaks. Technician B says that this can be due to the gas cap not being tightened properly. Who is correct?

Both Technician A and Technician B

Technician A says that the purge valve is part of the evaporative emissions system. Technician B says that OBDII systems must illuminate the MIL when the emissions exceed 1.5 times the FTP. Who is correct?

Both Technician A and Technician B

Technician A states that a DTC is set if the electrical system of a secondary air injection system fails. Technician B states that a check engine light is also illuminated at that instance of component failure. Who is correct?

Both Technician A and Technician B

During the reinstallation of the PCV valve, the _______ should be removed from the air cleaner assembly.

Breather tube

Particulates from modern engines are usually small particles of ________.

Carbon

Identify the reason a catalytic converter can fail when a catalyst becomes coated by a substance such as lead from leaded fuel.

Contamination

Which of the following is NOT an example of emissions testing equipment?

DMM/test light

If a vehicle passes a(n) ________ test with clean results, that is a good indication that all of the engine systems and the engine itself are operating well.

Emissions

Low tail pipe ________ mean a vehicle is running efficiently, which helps to conserve energy.

Emissions

Carbon monoxide is a colorless, odorless, tasteless, ________, and highly toxic gas.

Flammable

There are two primary pre-combustion emissions control systems: the _______ system and the _______ system.

Heated air intake; exhaust gas recirculation

In case of a leak in the EVAP system, _______ can be released into the atmosphere.

Hydrocarbons

________ is/are created when raw fuel evaporates into the atmosphere or when it does not burn at all in the combustion chamber and is exhausted out the tailpipe.

Hydrocarbons

If the EGR valve of a vehicle is stuck in an open position, the engine will ________.

Idle excessively roughly

If engine operating conditions are likely to produce oxides of nitrogen, the EGR valve opens, letting some burned exhaust gases pass from the exhaust into the __________ system.

Intake

Which of the following is a function of the positive crankcase ventilation (PCV) system?

It directs blowby gases and vapors back into the intake manifold.

Technician A says that allowing hot exhaust gases into the engine through the EGR valve helps to warm up the engine during warm-up. Technician B says that rich fuel mixtures create low amounts of carbon monoxide. Who is correct?

Neither Technician A nor Technician B

Pressure buildup in the crankcase of a vehicle can cause _______.

Oil seals and gaskets to leak oil

Catalytic converters come in two types: ________ and ________.

Oxidizing; reduction

What DTC will be set by the PCM if the ECM detects a large leak in the EVAP system?

P0455

What DTC will be set by the PCM if the ECM detects a small leak in the EVAP system?

P0456

Identify the system that is used to remove blowby gases from the crankcase in an environmentally friendly manner.

PCV system

A drivability concern caused by an EGR valve is called _______ and is a pre-ignition or detonation concern.

Pinging

_______ treatment focuses on assuring that combustion happens in a controlled and complete manner that minimizes post combustion pollutant gases.

Pre-combustion

What will happen if blowby gases are not removed from the crankcase of a vehicle?

Pressure build up can occur

In the combustion chamber, where surface temperatures are low, the combustion flame can be ________.

Quenched

The reduction catalyst in a catalytic converter helps to:

Reduce the oxides of nitrogen molecules into their base compounds.

When the catalyst of a catalytic converter is contaminated with lead and silicone, then the converter must be typically _______.

Replaced

Identify a drivability concern typically caused by EGR valves.

Rough idle concern

The ________ effect occurs when the exhaust gases moving out of the combustion chamber create a low-pressure area in the exhaust manifold, helping to pull air and fuel into the cylinder.

Scavenging

First aid for victims of carbon monoxide poisoning starts with recognizing the signs of exposure: ________, nausea, headache, dizziness, or light-headedness.

Shortness of breath

In vehicles with cracks and leaks that result in an EVAP system failure, the use of a(n) _______ may be necessary to find the leaks in the system.

Smoke machine

There are two common types of electric EGR valves: the pulse-width-modulated solenoid type and the _______ motor EGR valve type.

Stepper

Which of the following is NOT a measured gas when using a five gas analyzer?

Sulfur dioxide

Technician A says that hydrocarbons are created when raw fuel does not burn completely in the combustion chamber and is exhausted out the tailpipe. Technician B says that hydrocarbons are created when raw fuel evaporates into the atmosphere. Who is correct?

Tech A

Technician A says that overheated catalysts cannot be restored and must be replaced. Technician B says that overheated catalysts can be easily restored by driving the vehicle for an extended time under a moderate load. Who is correct?

Tech A

Technician A says that the MIL light is the first indication of trouble on an emissions control system. Technician B says that all states require yearly inspections of all of the emissions control devices. Who is correct?

Tech A

Technician A says that the PCV system recirculates exhaust gases into the intake manifold. Technician B says that the PCV system recirculates blowby gases into the intake manifold. Who is correct?

Tech B

Technician A says that if the EVAP system continues to purge at idle, a rough idle could be created. Technician B says that even a small fault in the EVAP system creates drivability issues. Who is correct?

Technician A

Technician A says that testing the secondary air injection system starts with checking for any related DTCs. Technician B says that all new vehicles have a secondary air injection system. Who is correct?

Technician A

Technician A says that the secondary air injection pump may be either electrically or belt driven. Technician B says that the secondary air injection pump is only used when the engine is fully warmed up to help cool the catalytic converter. Who is correct?

Technician A

Technician A says that to diagnose abnormal exhaust color, it is important to understand what each color represents. Technician B says that the color of exhaust cannot help diagnose abnormal exhaust. Who is correct?

Technician A

Technician A states that pinging can be referred to as the sound of marbles being shaken in a glass jar. Technician B states that pinging can be referred to as the sound of water gushing in a pipe. Who is correct?

Technician A

Technician A says that air should be injected into the exhaust manifold at all times. Technician B says that air should not be injected into the exhaust manifold at all times. Who is correct?

Technician B

Technician A says that secondary air injection is only used on vehicles equipped with a three-way catalytic converter. Technician B says that secondary air injection systems may not be needed due to efficient engine designs and reduced emissions. Who is correct?

Technician B

Technician A says that the EGR valve does not function at idle. Technician B says that the EGR valve will not function during WOT. Who is correct?

Technician B

Technician A says that the PCV system recirculates exhaust gases into the intake manifold. Technician B says that there are three different types pf PCV systems. Who is correct?

Technician B

A blue colored exhaust typically means that ________.

The engine is burning oil

If a crankcase pressure issue is not resolved, it may cause __________.

The gasket to pop out of place

The first step in controlling engine emissions is to design the engine in such a way as to reduce emissions as much as possible, such as building ________-enhancing strategies and precisely controlling valve and spark timing.

Turbulence

The most common PCV system problem is a ________ leak.

Vacuum

If the PCV valve is located in the _______, the PCV valve should be removed and ensured that a strong vacuum is coming through the valve with the engine running.

Valve cover

In which of these cases is the catalytic converter most likely to be saved?

When contaminated by carbon

Technician A says that overheated catalysts cannot be restored and must be replaced. Technician B says that overheated catalysts can be easily restored by driving the vehicle for an extended time under a moderate load. Who is correct?

When the catalyst is coated by silicone from improper sealants.

There is one condition when oxides of nitrogen are being created in large amounts and the EGR valve does not operate; it is _______.

When the vehicle is operated at WOT