ASE Ignition Systems

Question 1

What is the primary purpose of the ignition coil in a gasoline engine?

Accepted Answer

To step up battery voltage to fire spark plugs

Answer

The ignition coil transforms 12V battery voltage into the 20,000–45,000V needed to arc across the spark plug gap and ignite the air-fuel mixture.

Question 2

Which type of ignition system eliminates the need for a distributor entirely?

Accepted Answer

Distributor-less ignition system (DIS)

Answer

A distributor-less ignition system (DIS) uses multiple ignition coils controlled directly by the PCM to fire cylinders without any mechanical distribution of spark.

Question 3

In a distributor-based ignition system, what mechanism advances spark timing as engine RPM increases?

Accepted Answer

Centrifugal flyweight advance

Answer

The centrifugal advance mechanism uses flyweights inside the distributor that move outward at higher RPM, mechanically advancing ignition timing.

Question 4

What is the typical voltage range produced by the secondary ignition circuit?

Accepted Answer

20,000–45,000 volts

Answer

The secondary ignition circuit produces 20,000 to 45,000 volts — enough to ionize the air-fuel mixture and create a reliable spark under compression.

Question 5

What instrument is used to read and set ignition timing on older distributor-equipped vehicles?

Accepted Answer

Timing light (stroboscope)

Answer

A timing light flashes in sync with cylinder #1 firing, freezing the timing mark on the harmonic balancer so the technician can read and adjust base timing.

ASE - Automotive Service Excellence Certified Tech Practice Test

ASE - Automotive Service Excellence Certified Tech Practice Test

ASE Ignition Systems