Seeing your spark plug wires "light up" – emitting a visible glow or arc – is a serious issue that shouldn't be ignored. This phenomenon indicates a significant problem within your vehicle's ignition system, posing potential dangers and requiring immediate attention. This article will delve into the causes, risks, and effective solutions for this problem.
Why Are My Spark Plug Wires Glowing?
The most common reason for glowing spark plug wires is high voltage leakage. This occurs when the high voltage generated by the ignition coil cannot be properly contained within the wires, leading to arcing. Several factors can contribute to this:
- Worn or Damaged Wires: Over time, the insulation on spark plug wires degrades. Cracks, cuts, or even simple wear and tear can compromise the insulation, allowing the high voltage to escape. This is the most frequent culprit.
- Loose or Corroded Connections: Poor connections at the spark plug, distributor cap (if applicable), or coil pack create high resistance points. This resistance forces the voltage to find an easier path, resulting in arcing along the wire's exterior.
- Faulty Ignition Coil: A malfunctioning ignition coil can produce excessively high voltage, overwhelming the insulation of the spark plug wires. This is often accompanied by other ignition system issues.
- Moisture or Contamination: Water, dirt, or other contaminants on the wires can reduce their insulation resistance, leading to arcing. This is particularly problematic in humid or wet conditions.
- Incorrect Wire Routing: Improperly routed wires can be closer to metal components of the engine, increasing the likelihood of arcing.
Is It Dangerous to Drive with Glowing Spark Plug Wires?
Yes, absolutely. Driving with glowing spark plug wires is extremely dangerous for several reasons:
- Fire Hazard: The high-voltage arcing can easily ignite flammable materials in the engine compartment, leading to a potentially catastrophic fire.
- Engine Misfire: The voltage leakage prevents the full voltage from reaching the spark plugs, causing misfires and poor engine performance. This can lead to damage to the catalytic converter.
- Electrical Shock: Though less likely, the high voltage can pose a risk of electric shock if touched while the engine is running.
How Can I Fix Glowing Spark Plug Wires?
Addressing this issue requires a systematic approach:
1. Inspect the Spark Plug Wires:
Carefully examine each wire for any signs of damage, such as cracks, cuts, or worn insulation. Replace any wires showing even minor damage.
2. Check the Connections:
Inspect all connections at the spark plugs, distributor cap (if equipped), and coil pack. Ensure they are clean, tight, and free of corrosion. Clean any corroded terminals with a wire brush and apply dielectric grease to prevent future corrosion.
3. Test the Ignition Coil:
A faulty ignition coil is a common cause of high voltage leakage. This usually requires professional testing equipment to confirm proper operation. Replacing a faulty coil is often necessary.
4. Clean the Wires:
If the wires appear clean and undamaged, clean them thoroughly with a suitable cleaner to remove any dirt, grease, or moisture. Allow them to dry completely before restarting the engine.
5. Correct Wire Routing (If Necessary):
If the wires are routed too close to metallic components, carefully reroute them to maintain a safe distance.
6. Replace Spark Plugs:
While not directly related to the glowing wires, worn spark plugs can contribute to increased voltage requirements and worsen the problem. Replacing them with new, correctly gapped plugs is often a good preventative measure.
What are the Signs of a Bad Spark Plug Wire?
Besides glowing wires, other signs of a bad spark plug wire include:
- Rough engine idling: The engine might shake or rumble more than usual.
- Decreased fuel economy: Misfires waste fuel.
- Check engine light: The car's onboard computer will detect misfires and illuminate the check engine light.
- Difficulty starting: The engine might struggle to start or take longer to crank.
Ignoring glowing spark plug wires is a recipe for disaster. Addressing the underlying issue promptly is crucial to prevent engine damage, fire hazards, and ensure your safety. If you're unsure about any aspect of the repair, consult a qualified mechanic.
