A technician is performing a comprehensive inspection of a vehicle's ignition system. They notice significant white, powdery corrosion on the terminals inside the distributor cap and on the rotor tip. The vehicle owner reports occasional hesitation and misfires, especially in damp weather. What is the most likely impact of this corrosion on the ignition system's performance?
- AIt creates excessive resistance in the secondary circuit, hindering high voltage transfer and causing spark plug misfires.
- BIt increases the primary circuit resistance, leading to a weaker magnetic field in the coil.
- CIt accelerates the wear of the spark plug electrodes due to increased current flow.
- DIt causes a direct short circuit, preventing any spark from reaching the spark plugs.
Show answer & explanationAnswer & explanation
Correct answer: A. It creates excessive resistance in the secondary circuit, hindering high voltage transfer and causing spark plug misfires.
White, powdery corrosion on distributor cap terminals and the rotor tip significantly increases resistance in the secondary ignition circuit. This impedes the flow of high voltage from the coil to the spark plugs, making it harder for the spark to jump the gap, leading to misfires and hesitation, especially when damp conditions further reduce insulation.
Why the other options are wrong
- B. Corrosion in the cap/rotor affects the secondary (high voltage) circuit, not typically the primary circuit resistance.
- C. Increased resistance would decrease, not increase, current flow to the spark plugs, thus not accelerating electrode wear.
- D. While severe corrosion can cause misdirection of spark, it's more likely to impede than directly short the circuit, preventing all spark.
Distributor Cap Corrosion Effects
Corrosion on distributor cap terminals and rotor tip introduces high resistance into the secondary ignition circuit, impeding high-voltage delivery and causing misfires.
- Acts as an insulator/resistor.
- Worsens in damp conditions.
- Leads to misfires and hesitation.
Memory trick: Corrosion is like 'rust' in the 'spark's path', making it 'harder' to 'jump'.