Question 1

All the following elements except _____ are used in the spark plug center electrode to increase plug life.

Accepted Answer

Cesium is not used in spark plug center electrodes. Platinum, iridium, and yttrium are all commonly used in spark plugs to increase their longevity and performance.

Question 2

Which of the following components is part of the primary ignition circuit?

Accepted Answer

The ignition switch is part of the primary ignition circuit, as it controls the flow of electricity from the ignition system to the rest of the vehicle, initiating the ignition process.

Question 3

Spark plug design is being discussed. Technician A says a plug with too short a reach makes it difficult to attach the plug wire boot. Technician B says a plug with too long a reach may cause preignition. Who is correct?

Accepted Answer

The answer of Spark plug design is being discussed. Technician...

Question 4

Technician A says a plug with a V-notch ground electrode will have two electric arcs jumping across the spark plug gap each time the spark plug fires. Technician B says a spark plug gap that is too wide requires higher voltage to jump the gap, which can cause a misfire. Who is correct?

Accepted Answer

The answer of Technician A says a plug with a...

Question 5

Which of the following is NOT a spark plug thread diameter?

Accepted Answer

Spark plug thread diameters typically include sizes such as 10mm, 12mm, 14mm, and 18mm. The 9/16 inch size is not a standard spark plug thread diameter.

Question 6

Crankshaft sensors are being discussed. Technician A says the signal from a Hall-effect CKP cannot be used to synchronize fuel injector timing with the engine. Technician B says some early distributor ignition systems relied on photoelectric sensors to monitor crankshaft position. Who is correct?

Accepted Answer

Technician B is correct. Some early distributor ignition systems did rely on photoelectric sensors to monitor the crankshaft position. Technician A is incorrect because the signal from a Hall-effect CKP can be used to synchronize fuel injector timing with the engine.

Question 7

While discussing electronic ignition systems, Technician A says an NPN transistor in the PCM or ignition module controls primary current flow through the coil. Technician B says coil saturation is controlled by the length of time the primary ignition current is turned on. Who is correct?

Accepted Answer

Both Technician A and Technician B are correct. An NPN transistor in the PCM or ignition module controls primary current flow through the coil, and the coil saturation is controlled by the length of time the primary ignition current is turned on. The combination of these two factors allows for precise control of the ignition timing and spark duration.

Question 8

The heat range of a spark plug is indicated by ______.

Accepted Answer

The heat range of a spark plug is typically indicated by a code within the plug number imprinted on the side of the spark plug. This code helps identify the plug's ability to dissipate heat.

Question 9

Resistor-type spark plugs are being discussed. Technician A says the resistor increases the plug firing voltage. Technician B says the resistor helps reduce radio frequency interference [RFI], which can interfere with, or damage, radios, computers, and other electronic accessories, such as GPS systems. Who is correct?

Accepted Answer

Both technicians are correct. The resistor in spark plugs helps to reduce radio frequency interference (RFI) by suppressing voltage spikes and electromagnetic interference, and it also increases the firing voltage of the plug for improved ignition performance.

Question 10

The typical amount of secondary coil voltage required to jump the spark plug gap is ____ volts.

Accepted Answer

The typical amount of secondary coil voltage required to jump the spark plug gap is about 10,000 volts. This high voltage is necessary to create a spark that can ignite the air-fuel mixture in the combustion chamber.

Question 11

One of the advantages of a coil-on-plug type ignition system is that it eliminates the need for ______.

Accepted Answer

Coil-on-plug ignition systems have a coil directly attached to each spark plug, eliminating the need for spark plug wires.

Question 12

Technician A says spark plugs are part of the secondary ignition circuit. Technician B says the battery is part of the primary ignition circuit. Who is correct?

Accepted Answer

Technician A is correct because spark plugs are indeed part of the secondary ignition circuit, which includes components that deliver the high voltage needed to ignite the air/fuel mixture. Technician B is also correct because the battery is part of the primary ignition circuit, providing the initial electrical power needed to start the ignition process.

Question 13

Which of the following is not a type of electronic ignition system?

Accepted Answer

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

Question 14

Computer-controlled ignition timing is being discussed. Technician A says when excessive wheel slippage occurs, the PCM will advance the timing to increase the torque output from the engine. Technician B says to provide smooth shifting of an automatic transmission, the PCM will temporarily retard the ignition timing to reduce the engine's torque when the transmission is beginning to change gears.

Accepted Answer

The answer of Computer-controlled ignition timing is being discussed. Technician...

Question 15

Technician A says a magnetic pulse generator type sensor generates a small AC voltage each time one of the machined slots in the trigger wheel passes by. Technician B says some ignition systems use dual Hall-effect sensors that produce a 3x and 18x/revolution pulse. Who is correct?

Accepted Answer

Technician A is correct because a magnetic pulse generator type sensor does generate a small AC voltage each time one of the machined slots in the trigger wheel passes by. Technician B is also correct as some ignition systems do use dual Hall-effect sensors that produce a 3x and 18x/revolution pulse.

Question 16

In EI systems using one ignition coil for every two cylinders, Technician A says two plugs fire at the same time, with one wasting the spark on the exhaust stroke. Technician B says one plug fires in the normal direction and the other in reversed polarity. Who is correct?

Accepted Answer

In Electronic Ignition (EI) systems that use one ignition coil for every two cylinders, both statements are correct. Two plugs do fire at the same time, with one spark being wasted on the exhaust stroke (waste spark system), and one plug fires in the normal direction while the other fires in reversed polarity. This design is used to simplify the ignition system and reduce the number of required coils.

Question 17

Coil-over-plug ignition systems are being discussed, Technician A says COP coils have less time between each firing cycle, which increases the heat in the coil and can cause premature failure. Technician B says the COP system allows the ignition timing for each cylinder to be individually changed for maximum performance as the system responds to knock sensor signals. Who is correct?

Accepted Answer

Technician B is correct - the COP system allows for individually changing ignition timing for each cylinder for maximum performance, as the system can respond to knock sensor signals. Technician A is incorrect in saying that COP coils have less time between firing cycles, as this is not a characteristic or issue specific to COP systems.

Question 18

Ignition timing is being discussed. Technician A says when the engine idle speed moves away from the desired idle speed, the PCM will adjust the timing to stabilize the engine speed. Technician B says when a knock is detected, the PCM retards the timing in fixed steps until the knock disappears. Who is correct?

Accepted Answer

Both technicians are correct. Technician A is referring to the PCM's ability to adjust the ignition timing based on various inputs (such as engine speed) to maintain a stable idle. Technician B is referring to the PCM's ability to detect knock (a knocking or pinging noise) and retard the ignition timing to prevent engine damage. The PCM does this in fixed steps until the knock disappears, which helps ensure consistent engine performance and reliability.

Question 19

Spark plug wires are being discussed. Technician A says silicon-insulated wires are used for normal temperature applications. Technician B says hypalon-insulated wires are used for high-temperature applications. Who is correct?

Accepted Answer

Silicon-insulated wires are typically used for high-temperature applications, while hypalon-insulated wires are not commonly used for spark plug wires.

Question 20

EI systems are being discussed. Technician A says a waste spark system has one coil per cylinder. Technician B says a coil-on-plug system uses a double-ended coil. Who is correct?

Accepted Answer

A waste spark system typically uses a double-ended coil to serve two cylinders, not one coil per cylinder. A coil-on-plug system has one coil per spark plug, directly over the plug, and does not use a double-ended coil.

Quiz 26: Ignition Systems