Ignition System; Vacuum Fittings And Hoses; Spark Plugs; Spark Plug Condition - Jeep J-10 Series 1982 Technical & Service Manual

1A-16 GENERAL SERVICE ANO DIAGNOSIS
tube opening). If the filter is deteriorated, replace the
filler cap.
Drive Belts
Inspect belts for defects such as fraying or cracking.
Test belt tension. Belt tension testing, adjustment, ar
rangement and tension specifications are listed in Chap
ter 1C—Cooling Systems.
Vacuum Fittings and Hoses
Inspect vacuum hose fittings for looseness and corro
sion. Inspect rubber hoses for brittleness and cracking.
Thoroughly inspect the hose ends that are slipped onto
nipples. Engine performance may be adversely affected
by air leaks in such unlikely places as the heater and air
conditioner control vacuum hoses, Cruise Command
hoses or the power brake booster vacuum hose.
IGNITION SYSTEM
Spark Plugs
Remove and examine spark plugs for burned electro
des and fouled, cracked or broken porcelain insulators.
Keep plugs arranged in the order removed from the
engine. An isolated plug displaying an abnormal condi
tion indicates that a problem exists in the cylinder from
where it was removed. Replace plugs at the mileage
interval recommended in the Engine Maintenance
Schedule. Plugs that have less engine mileage may be
cleaned and reused if not otherwise defective. Refer to
Spark Plug Condition. After cleaning, file the center
electrode flat with a point file. Adjust the gap (separa
tion) between electrodes to 0.033-0.038 inch (0.84-0.97
mm) for six- and eight-cylinder engines, and 0.060 inch
(1.52 mm) for four-cylinder engines (fig. 1A-2).
-*v
42025
Fig. 1A-2 Spark Plug Gap Measurement—Typical
Always use a torque wrench when installing spark
plutfs. Distortion from overtightening will change the
gap (separation) of the plug electrodes. For four- and
six-cylinder engines, tighten plugs with 7 to 15 foot
pounds (9.5 to 23 N«m) torque. For eight-cylinder en
gines, tighten plugs with 25 to 30 foot-pounds (34 to 41
N*m) torque.
Spark Plug Condition
Refer to figure 1A-3. Compare the spark plugs with
the illustrations and the following descriptions.
LOW MILEAGE PLUGS WITH THIS CONDITION MAY BE CLEANED •• PLUGS WITH THIS CONDITION MUST BE REPLACED
Fig. 1A-3 Typical Spark Plug Conditions 60770
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