Spark Plug Inspection - Illustration (Solid State) - Ford VSG-411 Service Manual

2A-07
Ignition System
2A-07
IDENTIFIED BY DEPOSIT
BUILDUP CLOSING GAP
BETWEEN ELECTRODES.
CAUSED BY OIL OR
CARBON FOULING.
REPLACE PLUG, OR, IF
DEPOSTIS ARE NOT
EXCESSIVE, THE PLUG
CAN BE CLEANED.
IDENTIFIED BY WET BLACK
DEPOSITS ON THE
INSULATOR SHELL BORE
ELECTRODES.
IDENTIFIED BY BL
FLUFFY CARBON
INSULATOR TIPS,
SHELL SURFACES AN
ELECTRODES.
CAUSED BY TOO COLD A PLUG,
WEAK IGNITION, DIRTY AIR
CLEANER, DEFECTIVE FUEL
PUMP, TOO RICH A FUEL
MIXTURE, IMPROPERLY
OPERATING HEAT RISER OR
EXCESSIVE IDLING. CAN BE
CLEANED.
IDENTIFIED BY LIG
DEPOSITS ON THE
IDENTIFIED BY MELTED
ELECTRODES AND POSSIBLY
BLISTERED INSULATOR.
METALIC DEPOSITS ON
INSULATOR INDICATE ENGINE
CAUSED BY WRONG TYPE OF
FUEL, INCORRECT IGNITION
TIMING OR ADVANCE, TOO HOT
A PLUG, BURNT VALVES OR
ENGINE OVERHEATING.
REPLACE THE PLUG.
OVERHEATING
IDENTIFIED BY A WHITE
OR LIGHT GRAY
INSULATOR WITH SMALL
BLACK OR GRAY BROWN
SPOTS AND WITH BLUISH
BURNTAPPEARANCEOF
ELECTRODES.
CAUSED BY ENGINE
OVERHEATING, WRONG
TYPE OF FUEL, LOOSE
SPARK PLUGS, TOO HOT A
PLUG, LOW FUEL PUMP
PRESSURE OR
INCORRECT IGNITION
TIMING. REPLACE THE
PLUG.
FUSED SPOT DEPOSIT
IDENTIFIED BY MELTED OR
SPOTTY DEPOSITS RESEMBLING
BUBBLES OR BLISTERS.
CAUSED BY SUDDEN
ACCELERATION. CAN BE
CLEANED IF NOT EXCESSIVE,
OTHERWISE REPLACE PLUG.
FIG. 11 Spark Plug Inspection