How to Measure a Spark Plug Gap
The gap on the spark plug of your vehicle is the distance between the center and side electrodes. This gap needs to be calibrated to manufacturer specifications for your own particular car model. This ensures the spark can easily jump between the electrodes to ignite the air-fuel mixture entering the cylinders. From time to time, it is a good idea, to not only verify the spark plug gap, but also inspect and clean the plugs for better performance. Here we will go through the steps to inspect, clean and measure the gap as part of your car maintenance schedule.
Other People Are Reading
Things You'll Need
- Ratchet and spark plug socket
- Ratchet extension
- Steel wool brush
- Brake parts cleaner
- Shop rag
- Small diamond file
- Wire feeler gauge
Instructions
-
-
1
Grab the spark-plug wire boot. Then twist and pull off the wire from the spark plug. If your vehicle is equipped with Coil on Plug (COP) or Distributorless ignition system, consult your car owner's manual or vehicle service manual to remove the coils from the plugs, if necessary.
-
2
Unscrew the spark plug using a ratchet, ratchet extension and spark plug socket.
-
-
3
Inspect the condition of the spark plug. Look for oil, ash or carbon deposits that might indicate oil leaks or engine mechanical problems. The tip of the plug should have a brown or grayish-tan color.
-
4
Clean the plug threads and electrodes with a fine wire or steel wool brush.
-
5
Spray the electrodes and threads with brake parts cleaner and wipe the plug with a shop rag. If necessary, remove any carbon deposits from the center and side electrodes using a small diamond file.
-
6
Look up the correct gap for the spark plug on your vehicle. You should find this information on your car owner's manual or the Vehicle Emissions Control Information (VECI) label. This is a white, plastic coated label of about 4 by 6 inches in size, located on the radiator support, firewall or sides of the engine compartment.
-
7
Verify the spark plug gap by sliding a wire feeler gauge between the side and center electrodes. The wire should drag a little bit as it moves between the electrodes. If necessary, adjust the gap by bending the side electrode with the gauge tool.
-
8
Replace the spark plug and connect the spark plug wire making sure the wire-boot connector snaps in place on the spark plug terminal.
-
9
Clean, measure and adjust the rest of the spark plugs following Step 1 through 8.
-
1
References
- Photo Credit Photo courtesy of Sonett72 at Wikipedia.org.
