Jeep Engines - Oljeep

4.0L. POWER TECH IN-LINE 6 (IGNITION SYSTEM) 245Spark Plug and Ignition Wire RemovalRemove the ignition wire by grasping it at the spark plugboot, and then turn (1/2 turn) and pull it straight back in onesteady motion.1. Prior to removing the spark plug, spray compressed airaround the spark plug hole and the area around thespark plug.2.3.Remove the spark plug using a quality socket with arubber or foam insert.Inspect the spark plug. (Refer to Inspection.)InspectionFaulty and fouled plugs may perform well at idle speed, butat higher engine speeds they frequently fail. Faulty plugscan be identified in a number of ways: poor fuel economy,power loss, decrease in engine speed, hard starting and, ingeneral, poor engine performance. Spark plugs alsomalfunction because of carbon fouling, excessive air gap,or a broken insulator.Examine the spark plugs for burned electrodes and fouled,cracked or broken porcelain insulators. Keep plugsarranged in the order in which they were removed from theengine. An isolated plug displaying an abnormal conditionindicates that a problem exists in the correspondingcylinder. Replace spark plugs at the intervals recommendedon the Maintenance Chart in the service manual.Spark plugs that have low mileage may be cleaned and reusedif not otherwise defective. After cleaning, file the centerelectrode flat with a small point file or jewelers file. Adjustthe gap between the electrodes to the specified dimensions.SpecificationsNote: Due to model year differences, refer to the properservice or owners manual for spark plug type, gap, andtightening specifications.Gap AdjustmentCheck the spark plug with a gap (feeler) gauge. If the gapis not correct, adjust it by bending the ground electrode.Refer to the proper service or owners manual for spark pluggap specifications.Installation1. Start the spark plug into the cylinder head by hand toavoid cross threading.2.3.Tighten the spark plug to specified torque. Refer to theproper service or owners manual for torquespecifications.Install ignition wires over spark plugs.Always tighten spark plugs to the specified torque. Overtightening can cause distortion resulting in a change in thespark plug gap. Tighten all spark plugs to 35 Nom (27 ft-lbs).When replacing the ignition wires, route the wirescorrectly and secure them in the proper retainers. Failure toroute the wires properly can cause ignition noise radioreproduction, cross ignition of the spark plugs or shortcircuitthe wires to ground.SPARK PLUG CABLES (IGNITION WIRES)Check spark plug cable connections for good contact at theignition coil, distributor terminals, and spark plugs.Terminals should be fully seated. The nipples and spark plugcovers should be in good condition. Nipples should fittightly. Spark plug boot should completely cover the sparkplug hole in the cylinder head cover. Install the boot until theterminal snaps over the spark plug. A snap must be felt toensure the spark plug cable terminal engaged the spark plug.Loose cable connections will corrode, increase resistance,and permit water to enter. These conditions can causeignition malfunction. Plastic clips in various locationsprotect the cables from damage. When cables are replaced,the clips must be used to prevent damage to the new cables.If you don’t have top quality ignition wires you aren’tconducting maximum spark. Production spark plug wire is7 mm. For dual purpose and race-only applications, werecommend larger 7.5 mm spark plug wires. MoparPerformance Parts high performance 7.5 mm spark plugwires (P4286742) feature high quality insulation and boots(ends). If more insulation is required, neoprene hose of theproper inside diameter is recommended.Note: Using spark plug wires larger than 7.5 mm is NOTrecommended because of potential compatibility problemswith on-board computers and electronics.High Performance 7.5 mm Ignition Wire SetThis special high performance plug wire set features largerwire while maintaining compatibility with on-boardcomputer and electronics found in current productionvehicles. Package uses high tech production-style bootends at both the distributor and plug end of the wire. Wireis imprinted with the Mopar Performance Parts name. Thiscomplete set is pre-cut and fits all 1991-97 Jeep 4.0Lengines (only).P4286742High performance 7.5 mm ignitionwire set.