Grand Cherokee 2WD V8-4.7L VIN N (2000)
Spark Plug: Service and Repair
REMOVAL
In this engine, each individual spark plug is located under each ignition coil.
1. Prior to removing spark plug, spray compressed air around base of ignition coil at cylinder head. This will help prevent foreign material from
entering combustion chamber.
2. On this engine each individual ignition coil must be removed to gain access to each spark plug. Refer to Ignition Coil Removal/Installation.
3. Check condition of coil O-ring and replace as necessary.
3. Inspect spark plug condition. Refer to Spark Plug Conditions.
CLEANING
The plugs may be cleaned using commercially available spark plug cleaning equipment. After cleaning, file center electrode flat with a small point file
or jewelers file before adjusting gap.
CAUTION: Never use a motorized wire wheel brush to clean spark plugs. Metallic deposits will remain on spark plug insulator and will cause plug
misfire.
ADJUSTMENT
Setting Spark Plug Gap - Typical
Check spark plug gap with a gap gauge tool. If the gap is not correct, adjust it by bending ground electrode. Never attempt to adjust gap by bending
center electrode.
INSTALLATION
CAUTION: This engine is equipped with copper core ground electrode spark plugs. They must be replaced with the same type/number spark plug as
the original. If another spark plug is substituted, pre-ignition will result.
Special care should be taken when installing spark plugs into cylinder head spark plug wells. Be sure plugs do not drop into plug wells as ground
straps may be bent resulting in a change in plug gap, or electrodes can be damaged.
Always tighten spark plugs to specified torque. Over tightening can cause distortion resulting in a change in spark plug gap or a cracked porcelain
insulator.
1. Start spark plug into cylinder head by hand to avoid cross threading.
2. Tighten spark plugs to 27 Nm (20 ft. lbs.) torque.
3. Before installing coil(s), check condition of coil O-ring and replace as necessary. To aid in coil installation, apply silicone to coil O-ring.
4. Install ignition coil(s). Refer to Ignition Coil Removal/Installation.