Spark Plug: Description and Operation
SYSTEM OPERATIONAll engines use resistor spark plugs. They have resistance values ranging from 6,000 to 20,000 ohms when checked with at least a 1000 volt spark plug tester.
Do not use an ohm meter to check the resistance of the spark plugs. This will give an inaccurate reading.
Remove the spark plugs and examine them for burned electrodes and fouled, cracked or broken porcelain insulators. Keep plugs arranged in the order in which they were removed from the engine. An isolated plug displaying an abnormal condition indicates that a problem exists in the corresponding cylinder.
Spark plugs that have low mileage may be cleaned and used if not otherwise defective, carbon or oil fouled. Refer to the Spark Plug Condition. After cleaning, file the center electrode flat with a small flat point file or jewelers file. Adjust the gap between the electrodes to the dimensions specified in the chart.
Special care should be used when installing spark plugs in the 2.4L cylinder head spark plug wells. Be sure the plugs do not drop into the wells, damage to the electrodes can occur.
Always tighten spark plugs to the specified torque. Over tightening can cause distortion resulting in a change in the spark plug gap. Overtightening can also damage the cylinder head. Tighten spark plugs to 28 N.m (20 ft. lbs.) torque.