Spark Plug Wires; Spark Plug Wire Replacement - GMC G Service Manual

SPARK PLUG WIRES

PRECAUTIONS
1. Twist boots 1/2 turn before removing.
2. When removing the boot, do not use pliers or other
tools that could tear the boot.
3. Do not force anything between the wire and the boot,
or through the silicone jacket of the wire.
4. Do not pull on the wires to remove the boot. Pull on
the boot, or use a tool designed for this purpose.
5. Special care should be exercised when installing
spark plug boots to assure that the metal terminal
within the boot is fully seated on the spark plug termi­
nal and that the boot has not moved on the wire. If
boot to wire movement has occurred, the boot will
give a false visual impression of being fully seated. A
good check to assure that boots have been properly
assembled is to push sideways on the installed boots.
If they have been correctly installed, the boot will feel
stiff, with only slight looseness. If the terminal has not
been properly seated on the spark plug, only the
resistance of the rubber boot will be felt when pushing
sideways.
ENGINE ELECTRICAL 6P-45
SPARK PLUG WIRE
REPLACEMENT
Wire routings must be kept intact during service. When
wires have been disconnected, or when replacement of the
wires is necessary, specified routings must be followed pre­
cisely. Failure to route the wires properly can lead to radio
ignition noise and crossfiring of the plugs, or shorting of the
leads to ground. For the correct wiring routing for each
engine, refer to figures 54 through 64.
Some distributors have spark plug wire retainer harness
assemblies with the engine firing order marked on them. If
the firing order is not indicated, install the plug wires
according to the firing order as shown in figures 61, 62 and
63. When the wiring is completed, the plug wire from cylin­
der number 1 should lead to the distributor tower at the front
and on the same side of the engine as cylinder number 1.
The plug wire from cylinder number 6 (in 6 cylinder
engines) or from cylinder number 8 (in V8 engines) should
lead to the distributor tower at the front of the engine next to
the number 1 tower.
Be sure to position all plug boots perpendicular to the
centerline of the engine.
On the LE8 (7.4L V8) engine, the spark plug harness
assembly and dielectric paper insulator are fitted to a shield
which is installed over the spark plug (figure 64). The insu­
lator grounds the shield to the engine block. If the assembly
is removed from the shield, make sure that the insulator is
present and undamaged before reinstallation.