Ignition System Diagnosis and Repair Flashcards
6 cards from real ASE4 practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 6 Ignition System Diagnosis and Repair flashcards as text
A spark plug with a white or light gray insulator tip and no deposits indicates:
Answer: A lean mixture or overheating condition
A white or very light gray spark plug tip indicates a lean mixture or excessive heat, potentially from an air leak or cooling issue.
An ignition coil secondary resistance reads OL (open). This means:
Answer: The coil secondary winding is open and must be replaced
An OL (overload/open) reading on secondary resistance means the winding is broken open and the coil cannot produce spark.
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:
Answer: The coil is the cause of the misfire
A misfire that follows the swapped coil to a new cylinder confirms the coil itself is the source of the fault.
Ignition timing that is too far advanced will cause:
Answer: Hard starting and detonation under load
Over-advanced timing causes the mixture to ignite too early, resulting in engine knock (detonation) and hard starting.
A scan tool shows ignition timing retarded by 8° from base timing. This is MOST likely caused by:
Answer: The knock sensor detecting detonation
The ECM retards timing in response to knock sensor signals to protect the engine from detonation damage.
What is the function of the camshaft position sensor in a modern distributorless ignition system?
Answer: It identifies cylinder #1 TDC for sequential fuel and spark delivery
The CMP sensor identifies the #1 cylinder at TDC compression so the ECM can sequence coil firing and injector timing correctly.