Why Must the Spark Plugs be Inspected with a Fuel System Service?

July 8, 2011  

Very simple in theory, the spark plug forces electricity (40,000 – 100,000 Volts) across a specific gap. This high voltage electricity travels down an electrode and to the engine block, where the spark is grounded. The elegantly simple design of the spark plug:

  1. Must withstand high temperatures and pressure inside the cylinder
  2. Must minimize build-up from fuel additives and other debris on its surface

A vital component to a vehicle’s ignition, spark plugs often become ‘fouled’ (dirty) at the tip. When this happens, the spark from the plug will not ignite the fuel vapor properly, which can affect fuel efficiency and ultimately ignition. When a spark plug is fouled, it must be either cleaned or replaced. You will know when it’s time to check your car’s spark plugs — in severe cases, the engine will sputter as the plugs mis-fire.

Why is the Spark Plug Insert Ceramic?

The high voltage that passes through a spark plug is isolated at the tip of the electrode with a ceramic insert. This insert, which is a poor heat conductor, serves to also keep the spark plug clean. Because the ceramic gets extremely hot during operation, it helps burn off deposits from the electrode.

What is the Difference Between a Cold Plug and a Hot Plug?

It is essential when changing the spark plugs in your vehicle that you use the correct type of plug. Check your Owner’s Manual to determine which type of spark plug to use on your vehicle. If a spark plug gets too hot, it will ignite the fuel before it sparks.

  • Hot Plug — designed such that the ceramic insert is shaped to minimize contact with the electrode. Because the spark plug runs hot, it will burn more deposits of the electrode tip.
  • Cold Plug — designed with maximum ceramic insert to electrode contact area to decrease the running temperature at the plug. Used for high performance engines that tend to run extremely hot. Because the plug runs cooler, there is less risk of the fuel vapors igniting before the spark.

Spark Plug Maintenance

If your car is mis-firing due to fouled spark plugs, you may choose to clean, rather than replace the spark plugs:

  1. Remove — using a socket driver with a spark plug socket, remove all plugs
  2. Clean — by brushing any loose debris from the surface of spark plugs. With a quick drying liquid (pure alcohol, brake cleaner, mineral spirits, etc.), clean the firing tip of the plugs.
  3. Blow — using canned, pressurized air, remove remaining debris
  4. Clean again — using a dry compound, (even if the spark plug looks clean), to remove dirt not visible to the eye
  5. Blow again — as in Step 3
  6. Clean threads — using a wire brush, gently clean the threads
  7. Set gaps — using a gap tool, set the spark plug gaps according to your vehicle’s manufacturer recommendations
  8. Clean spark plug holes — using the same dry cleaner (if necessary), or simply wipe the holes with a clean rag
  9. Reinstall — spark plugs back into holes.

Should you decide to take this task on yourself, be certain that your car’s engine is completely cool. As spark plugs will eventually wear out, if your vehicle still does not run smoothly — consider replacing them. Rest assured, if you are not a do-it-yourselfer, a complete Lynwood Fuel System Service will assure that your vehicle runs smoothly at peak fuel efficiency!