Spark Plug Wire Check And Replacement; Distributor Cap And Rotor Check And Replacement - Jeep cherokee 1989 Owner's Manual

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plug. Pull only on the boot at the end of the wire
wire. A plug wire removal tool should be used if available (see illustra-
tion).
7 If compressed air is available, use it to blow any dirt or foreign ma-
terial away from the spark plug hole. A common bicycle pump will also
work. The idea here is to eliminate the possibility of debris falling into
the cylinder as the spark plug is removed.
8
Place the spark plug socket over the plug and remove it from the
engine by turning it in a counterclockwise direction.
9
Compare the spark plug t o those shown in the color photos on
page 1-35 to get an indication of the general running condition of the
engine.
10 Thread one of the new plugs into the hole until you can no longer
turn it with your fingers, then tighten it with a torque wrench (if avail-
able) or the ratchet. It might be a good idea to slip a short length of
rubber hose over the end of the plug to use as a tool to thread it into
place (see illustration). The hose will grip the plug well enough to turn
it, but will start to slip if the plug begins to cross-thread in the hole
this will prevent damaged threads and the accompanying repair costs.
11 Before pushing the spark plug wire onto the end of the plug, in-
spect it following the procedures outlined in Section 44.
12 Attach the plug wire to the new spark plug, again using a twisting
motion on the boot until it's seated on the spark plug.
13 Repeat the procedure for the remaining spark plugs, replacing
them one at a time to prevent mixing up the spark plug wires.
43.6 When removing the spark plug wires, pull only on
the boot and use a twistinglpulling motion
A
43.10 length of 3116-inch ID rubber hose will save time and
prevent damaged threads when installing the spark plugs
4 4 Svark plug wire check and replacement
1 The spark plug wires should be checked at the recommended in-
tervals and whenever new spark plugs are installed in the engine.
2 The wires should be inspected one at a time t o prevent mixing up
the order, which is essential for proper engine operation.
3 Disconnect the plug wire from one spark plug. To do this, grab
the rubber boot, twist slightly and pull the wire free. Do not pull on
the wire itself, only on the rubber boot (see illustration 43.6).
4 Check inside the boot for corrosion, which will look like a white
crusty powder. Push the wire and boot back onto the end of the spark
plug. It should be a tight fit on the plug. If it isn't, remove the wire
and use a pair of pliers t o carefully crimp the metal connector inside
the boot until it fits securely on the end of the spark plug.
5
Using a clean rag, wipe the entire length of the wire to remove
The Motor Manual Guy
Chapter 1
Tune-up and routine maintenance
-
do not pull on the
-
any built-up dirt and grease. Once the wire is clean, check for holes,
burned areas, cracks and other damage. Don't bend the wire exces-
sively or the conductor inside might break.
Disconnect the wire from the distributor cap. A retaining ring at
the top of the distributor may have t o be removed to free the wires.
Again, pull only on the rubber boot. Check for corrosion and a tight
fit in the same manner as the spark plug end. Reattach the wire to the
distributor cap.
7
Check the remaining spark plug wires one at a time, making sure
they are securely fastened at the distributor and the spark plug when
the check is complete.
If new spark plug wires are required, purchase a new set for your
specific engine model. Wire sets are available pre-cut, with the rubber
boots already installed. Remove and replace the wires one at a time
to avoid mix-ups in the firing order. The wire routing is extremely im-
portant, so be sure to note exactly how each wire is situated before
removing it.
--

4 5 Distributor cap and rotor check and replacement

Refer to illustrations 45.3 and 45.6
Note: It's common practice to install a new distributor cap and rotor
whenever new spark plug wires are installed.
Check
1 To gain access to the distributor cap, especially on a V6 engine,
may be necessary to remove the air cleaner assembly (see Chapter 4).
it
2 Loosen the distributor cap mounting screws (note that the screws
have a shoulder so they don't come completely out). On some models,
the cap is held in place with latches that look like screws
them, push down with a screwdriver and turn them about 112-turn.
Pull up on the cap, with the wires attached, to separate it from the
distributor, then position it to one side.
3 The rotor is now visible on the end of the distributor shaft. Check
it carefully for cracks and carbon tracks. Make sure the center terminal
spring tension is adequate and look for corrosion and wear on the rotor
tip (see illustration). If in doubt about its condition, replace it with a
new one.
4 If replacement is required, detach the rotor from the shaft and install
a new one. On some models, the rotor is press fit on the shaft and
can be pried or pulled off. On other models, the rotor is attached to
the distributor shaft with t w o screws.
5 The rotor is indexed to the shaft so it can only be installed one
way. Press fit rotors have an internal key that must line up with
in the end of the shaft (or vice versa). Rotors held in place with screws
have one square and one round peg on the underside that must fit in-
to holes with the same shape. Apply a very thin coat of silicone dielec-
tric compound to the rotor blade, if a new rotor is being installed.
6
Check the distributor cap for carbon tracks, cracks and other
INSUFFICIENT
SPRING
TENSION
\
ROTOR
PHYSICAL
TIP
CORRODED
CAP
The ignition rotor should be checked for wear and
45.3
corrosion as indicated here (if i n doubt about its condition,
buy a new one)
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to release
slot
a