Spark Plug Inspection - Illustration - Ford VSG-411 Service Manual

Ignition System
2-08
GAP BRIDGED
01 L FOULED CARBON FOULED
* . .
. . .::.. . . . . .? &. .
IDENTIFIED BY DEPOSIT IDENTIFIED BY WET BLACK DEP-
BUILD-UP CLOSING GAP
IDENTIFIED BY BLACK,
OSITS ON THE INSULATOR SHELL
DRY FLUFFY CARBON
BETWEEN ELECTRODES.
BORE ELECTRODES CAUSED BY DEPOSITS ON INSULATOR
CAUSED BY OiL OR EXCESSIVE OIL ENTERING COMBUS-
CARBON FOULING. REPLACE
TIPS, EXPOSED SHELL
TION CHAMBER THROUGH WORN
SURFACES AND ELECTRODES.
PLUG, OR, IF f' EPOSITS ARE RINGS AND PISTONS, EXCESSIVE
CAUSED BY TOO COLD A
NOT EXCESSIVE, THE PLUG
CLEARANCE BETWEEN VALVE
CAN BE CLEANED.
PLUG, WEAK IGNITION, DIRTY
GUIDES AND STEMS, OR WORN OR
AIR CLEANER, DEFECTIVE FUEL
LOOSE BEARINGS. REPLACE THE
PUMP, TOO RICH A FUEL
PLUG. IF ENGINE IS NOT REPAIRED,
MIXTURE, IMPROPERLY
USE A HOTTER PLUG.
OPERATING HEAT RISER
OR EXCESSIVE IDLING.
CAN BE CLEANED.
WORN
NORMAL LEAD FOULED
IDENTIFIED BY SEVERELY
ERODED OR
WORN ELECTRODES.
CAUSED BY NORMAL
WEAR.
SHOULD BE REPLACED
IDENTIFIED BY LIGHT TAN OR
GRAY DEPOSITS ON THE
FIRING TIP.
IDENTIFIED BY DARK
GRAY, BLACK, YELLOW
OR TAN DEPOSITS OR A
FUSED GLAZED COATING
ON THE INSULATOR TIP.
CAUSED BY HIGHLY
LEADED GASOLINE.
REPLACE THE PLUG.
PRE-IGNITION
,. . . . . ::>.. ::-: . . > . . .
. . ...% . ..z& . . . .
f% . =.. ..;.
. . ..y.py.'
.
v.:.::..
OVERHEATING
. .
.. . . .
FUSED SPOT DEPOSIT
' ... . v.
. .
. .
,.."
. i..:.. . f.:...: i' . .
. . . . . v:y...... :.* , :.:.:. . :
. . . . . . . . . . . . ...*. :.:.g.:.>
. . . . ..: ;. . :."
::..... ;>:..
. . .*:::::$$.:.:;:.::.:::&y.:.:.:.:.:.: . . . . . :.:.. .
. . . . . . . . . . . < . *.: ..,,
5.. :$& . . ..A . . . . . . . .
.*..... :.:.:.:.:.:.:.:.: 2..
. . . . . a... . . . . .
IDENTIFIED BY MELTED
ELECTRODES AND POSSIBLY
BLISTERED INSULATOR.
METALLIC DEPOSITS ON
INSULATOR INDICATE ENGINE
DAMAGE.
CAUSED BY WRONG TYPE
OF FUEL, INCORRECT IGNITION
TIMING OR ADVANCE, TOO HOT
A PLUG, BURNT VALVES OR
ENGINE OVERHEATING.
REPLACE THE PLUG.
. .
. . r:... : ....:.: .:I. . . . . . . . . : . :.:.:.:.. . . . . .
. . . . . . . . . . . . . . . . :.~..~.;.~.~.~.~
. .*.~...~.~.~.~.~.~.~.;.~.v A... . . . . ..J . . . . .:.. :.:.:.:.:~:.:~,*i&
IDENTIFIED BY A WHITE OR LIGHT
GRAY INSULATOR WITH SMALL
BLACK OR GRAY BROWN SPOTS
AND WITH BLUISH-BURNT APPEAR-
ANCE OF ELECTRODES, CAUSED
BY ENGINE OVERHEATING. WRONG
TYPE OF FUEL, LOOSE SPARK
PLUGS, TOO HOT A PLUG, LOW
FUEL PUMP PRESSURE OR INCOR-
RECT IGNITION TIMING. REPLACE
THE PLUG.
. ..' .: . .
. .* . . . A> A.+...&"
. .
. . . . . :.., . . . . f. . . . . . . . . . .
5 . . . . ...+. . ..: :. . . . ..>n. ,. . . .
. . :..:' :J . . . . y..:y ::::::.:y . . .
IDENTIFIED BY MELTED
OR SPOTTY DEPOSITS
RESEMBLING BUBBLES
OR BLISTERS.
CAUSED BY SUDDEN
ACCELERATION. CAN BE
CLEANED IF NOT EXCESSIVE.
OTHERWISE REPLACE PLUG.
FIG. 16 Spark Plug Inspection