ASE4 Ignition System Diagnosis and Repair 2

Question 1

A spark plug with a white or light gray insulator tip and no deposits indicates:

Accepted Answer

A lean mixture or overheating condition

Answer

A white or very light gray spark plug tip indicates a lean mixture or excessive heat, potentially from an air leak or cooling issue.

Question 2

An ignition coil secondary resistance reads OL (open). This means:

Accepted Answer

The coil secondary winding is open and must be replaced

Answer

An OL (overload/open) reading on secondary resistance means the winding is broken open and the coil cannot produce spark.

Question 3

A COP (coil-on-plug) ignition system has a misfire on cylinder #4. The technician swaps the coil from #4 to #7. If the misfire moves to cylinder #7, this indicates:

Accepted Answer

The coil is the cause of the misfire

Answer

A misfire that follows the swapped coil to a new cylinder confirms the coil itself is the source of the fault.

Question 4

Ignition timing that is too far advanced will cause:

Accepted Answer

Hard starting and detonation under load

Answer

Over-advanced timing causes the mixture to ignite too early, resulting in engine knock (detonation) and hard starting.

Question 5

A scan tool shows ignition timing retarded by 8° from base timing. This is MOST likely caused by:

Accepted Answer

The knock sensor detecting detonation

Answer

The ECM retards timing in response to knock sensor signals to protect the engine from detonation damage.

ASE4 - ASE Automobile Engine Performance Practice Test

ASE4 - ASE Automobile Engine Performance Practice Test

ASE4 Ignition System Diagnosis and Repair 2