Spark Plug Inspection Chart - Ford LRG-423 Service Manual

03-l 6 Auxiliary Systems
03-I 6
DISTRIBUTORLESS IGNITION SYSTEM CLEANING AND INSPECTION
Spark Plugs
Clean spark plugs (12405) as necessary using a wire
brush or professional spark plug cleaner (follow
manufacturer' s instructions). Inspect the firing tip.
Refer to Spark Plug Inspection Chart. Replace spark
plugs (12405) if they are worn or damaged.
Ignition Coil
Ignition Wires
Wipe the spark plug wire set (12259) with a clean,
damp cloth before inspecting it. Without removing the
spark plug wire set (12259) from the spark plugs
(12405) or ignition coil (12029) inspect the wire set for
visible damage such as cuts, pinches, or cracked or
torn boots. Refer to Ignition Wires Removal and
Installation in this section and replace as necessary.
Wipe the coil towers with a clean cloth dampened with
soap and water. Remove any soap film and dry with
compressed air. Inspect for cracks, carbon tracking
and dirt.
Spark Plug Inspection Chart
GAP BRIDGED
IDENTIFIED BY DEPOSIT BUILD-
UP CLOSING GAP BETWEEN
ELECTRODES.
CAUSED BY OIL OR CARBON
FOULING, REPLACE PLUG, OR
IF DEPOSITS ARE NOT EXCESSIVE
THE PLUG CAN BE CLEANED.
OIL FOULED
IDENTIFIED BY WET BLACK
DEPOSITS ON THE INSULATOR
SHELL BORE ELECTRODES.
CAUSED BY EXCESSIVE OIL
ENTERING COMBUSTION CHAMBER
THROUGH WORN RINGS AND
PISTONS, EXCESSIVE CLEARANCE
BETWEEN VALVE GUIDES AND
STEMS, OR WORN OR LOOSE
BEARINGS. CORRECT OIL
PROBLEM. REPLACE THE PLUG.
ELECTRODES.
CAUSED BY TOO COLD A PLUG,
NER, DEFECTIVE FUEL
H A FUEL MIXTURE,
PERATING HEAT RISER
IDLING. CAN BE
IDENTIFIED BY LIGHT TAN OR GRAY
METALLIC DEPOSiTS ON INSULATOR
DEPOSITS ON THE FIRING TIP.
INDICATE ENGINE DAMAGE.
CAUSED BY WRONG
IDENTIFIED BY A WHITE OR LIGHT
GRAY tNSULATOR WITH SMALL
BLACK OR GRAY BROWN SPOTS
AND WITH BLUISH-BURNT
APPEARANCE OF ELECTRODES.
IDENTIFIED BY MELTED OR SPOrrY
DEPOSITS RESEMBLING BUBBLES OR
BLISTERS.
CAUSED BY ENGINE OVER-
HEATING, WRONG IYPE OF
FUEL, LOOSE SPARK PLUGS. TOO
HOT A PLUG, LOW FUEL PUMP
PRESSURE OR INCORRECT IGNITION
TIMING. REPLACE THE PLUG.
CAUSED BY SUDDEN ACCELERATION.
CAN BE CLEANED IF NOT EXCESSIVE,
OTHERWISE REPLACE PLUG.
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