Question 1

As the rpm of an engine is increased, the ignition spark occurs:
A) earlier
B) later
C) at the same time
D) none of the above

Accepted Answer

As the rpm of an engine increases, the combustion process speeds up and therefore the ignition spark needs to occur earlier to ensure proper ignition timing.

Question 2

Technician A says a Hall Effect switch voltage signal goes from 12 V to 0 V when the rotating metal blade enters the switch. Technician B says a Hall Effect switch produces an analog voltage signal. Who is correct?
A) A only
B) B only
C) both A and B
D) neither A nor B

Accepted Answer

D

Question 3

The spark burn time line is the length of time that the spark plug is igniting (firing) the air/fuel mixture in the cylinder.

Accepted Answer

The statement is true.

Question 4

Changes in engine load also affect when the ignition spark should be delivered.

Accepted Answer

Changes in engine load affect the timing of the ignition spark because the engine requires different amounts of fuel and air mixture to compensate for the changes in load. The ignition timing must also be adjusted to ensure that the spark occurs at the correct time for optimal combustion.

Question 5

The long-life platinum spark plugs are capable of lasting 50,000 miles (80,467 km).

Accepted Answer

Platinum spark plugs typically last longer than 50,000 miles, often up to 100,000 miles, due to their durability and resistance to wear.

Question 6

An engine knock may occur due to:
A) low fuel octane
B) excessive carbon buildup in the combustion chamber
C) ignition spark occurring too early
D) all of the above

Accepted Answer

A low fuel octane can cause pre-ignition and engine knock, excessive carbon buildup can create hot spots that cause knocking, and an ignition spark that occurs too early can lead to knocking. Therefore, all of these factors can contribute to an engine knock.

Question 7

During testing with a secondary ignition system oscilloscope, a technician notices that all cylinders exhibit low coil kV output. Which of the following is the most likely cause?
A) faulty coil-to-plug insulation
B) high resistance in the primary control circuit
C) PCM has an open coil driver circuit
D) blown ignition fuse

Accepted Answer

A high resistance in the primary control circuit can result in low coil kV output for all cylinders. Faulty coil-to-plug insulation would normally affect one or a few cylinders, while an open coil driver circuit or blown ignition fuse would result in no spark at all.

Question 8

A misfire diagnostic trouble code (DTC) is stored for cylinder #4 (P0304) on a coil-on-plug EI system. Preliminary testing of components following manufacturer's recommended procedures are within acceptable ranges. Technician A says that water may have intruded into the recessed spark plug well in the cylinder head. Technician B says that the ignition extension tube should be inspected for carbon tracking. Who is correct?
A) A only
B) B only
C) both A and B
D) neither A nor B

Accepted Answer

The answer of A misfire diagnostic trouble code (DTC) is...

Question 9

Misfires are more likely to occur under lower engine speeds and decreased load conditions.

Accepted Answer

Misfires are more likely to occur under higher engine loads and speeds, where the combustion process is more demanding and any inefficiency in the fuel, air, or spark delivery is more pronounced.

Question 10

Technician A says the spark plugs are in the secondary ignition circuit. Technician B says the ignition module is part of the secondary ignition circuit. 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 the spark plugs are...

Question 11

A technician repaired a cold-start and hard-starting problem by replacing the secondary ignition wires and spark plugs. After the repair, the vehicle failed an emission test for high CO and HC levels. Technician A says a restriction in the fuel delivery system such as the fuel filter could be the problem. Technician B says that the engine oil could be contaminated with fuel. Who is correct?
A) A only
B) B only
C) both A and B
D) neither A nor B

Accepted Answer

The answer of A technician repaired a cold-start and hard-starting...

Question 12

The coil-on-plug design allows for increased coil saturation time between cylinder firing.

Accepted Answer

The coil-on-plug design places an individual ignition coil on each spark plug, allowing for increased coil saturation time between cylinder firing. This results in a more efficient and powerful ignition system.

Question 13

The ignition system on many newer cars has no:
A) distributor
B) coil
C) spark plugs
D) crank position sensor

Accepted Answer

Many newer cars use a different type of ignition system called a "coil on plug" system. Instead of using a distributor and a single coil to provide spark to all of the cylinders, each individual spark plug has its own ignition coil. This eliminates the need for a distributor, but the car still requires spark plugs and a crank position sensor.

Question 14

A higher than normal firing line voltage could be caused by a low secondary ignition resistance.

Accepted Answer

A low secondary ignition resistance would actually result in a lower firing line voltage. A higher than normal firing line voltage could be caused by a high secondary ignition resistance.

Question 15

The independent ignition system offers greater reliability and a lower incidence of cylinder misfires compared to past ignition systems.

Accepted Answer

The independent ignition system is designed to provide more reliable and efficient engine performance by minimizing the risk of cylinder misfires. This is achieved by using a separate ignition coil for each cylinder, which ensures that the fuel mixture is ignited at the right moment and with enough power to maintain consistent combustion. As a result, the engine runs smoother and with better fuel economy, making it a preferred choice for modern automotive engines.

Question 16

The vehicle manufacturer specification for spark plug heat range can be changed.

Accepted Answer

The vehicle manufacturer specifies the spark plug heat range to match the engine's operating conditions and ensure optimal performance. Changing the heat range without proper guidance can lead to engine damage or reduced efficiency.

Question 17

The spark plugs are fired at:
A) various times on the power stroke
B) 12 degrees BTDC on the compression stroke
C) 12 degrees ATDC on the power stroke
D) various times on the compression stroke

Accepted Answer

Spark plugs are typically fired at various times on the compression stroke to ensure optimal ignition timing for efficient combustion.

Question 18

A random misfire code P0300 is usually associated with an ignition system failure.

Accepted Answer

The answer of A random misfire code P0300 is usually...

Question 19

The coil-on-plug ignition system is sometimes referred to as a coil-over-plug ignition system.

Accepted Answer

The terms "coil-on-plug" and "coil-over-plug" are often used interchangeably to refer to the same ignition system. Both terms describe an ignition system where each spark plug has its own individual ignition coil.

Question 20

A secondary ignition oscilloscope pattern is being analyzed. The voltage spikes of cylinders #1, #2, and #3 are 9 to 12 kV while cylinder #4 is 35 kV. What is the most likely cause of this?
A) open plug wires for cylinders #1, #2, and #3
B) shorted spark plug
C) grounded plug wires
D) open plug wire for cylinder #4

Accepted Answer

The voltage spike for cylinder #4 is significantly higher than the other cylinders, indicating a problem with the ignition system specifically on that cylinder. An open plug wire for cylinder #4 is the most likely cause, as it would result in a loss of voltage to that cylinder which would cause the secondary ignition voltage to increase.

Quiz 6: Ignition System and Related Input Sensorsoutput Actuators Diagnosis

As the rpm of an engine is increased, the ignition spark occurs:

Technician A says a Hall Effect switch voltage signal goes from 12 V to 0 V when the rotating metal blade enters the switch. Technician B says a Hall Effect switch produces an analog voltage signal. Who is correct?

The spark burn time line is the length of time that the spark plug is igniting (firing) the air/fuel mixture in the cylinder.

Changes in engine load also affect when the ignition spark should be delivered.

The long-life platinum spark plugs are capable of lasting 50,000 miles (80,467 km).

An engine knock may occur due to:

During testing with a secondary ignition system oscilloscope, a technician notices that all cylinders exhibit low coil kV output. Which of the following is the most likely cause?

Misfires are more likely to occur under lower engine speeds and decreased load conditions.

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

The coil-on-plug design allows for increased coil saturation time between cylinder firing.

The ignition system on many newer cars has no:

A higher than normal firing line voltage could be caused by a low secondary ignition resistance.

The independent ignition system offers greater reliability and a lower incidence of cylinder misfires compared to past ignition systems.

The vehicle manufacturer specification for spark plug heat range can be changed.

The spark plugs are fired at:

A random misfire code P0300 is usually associated with an ignition system failure.

The coil-on-plug ignition system is sometimes referred to as a coil-over-plug ignition system.

A secondary ignition oscilloscope pattern is being analyzed. The voltage spikes of cylinders #1, #2, and #3 are 9 to 12 kV while cylinder #4 is 35 kV. What is the most likely cause of this?