16
Self-Test Part 3: Check Engine Timing.
HVAC/
CRUISE
BRAKE BOOSTER
FUEL
PRESS
REG
EGR
VAC
REG
EGR
VAC
REG
TO TRANS
MODE
. ..
9RAC2LAB
FRONT
OF CAR
GAP
.S.A.
STER
E M
S T
(NOTE: 7.3L
Diesel This
Part does
not apply. Go
to Part 4.)
This portion of
the Self-Test procedure is where you
check both the “base” engine timing (no
computer adjustment ) and the ability of
the computer to control spark advance.
The correct value for base engine timing
is printed on the Vehicle Emission
Control Information (VECI) decal, located
in the engine compartment. (Base timing
is 10° BTDC if not specified on the VECI
decal.) A timing light is required for this
test. Connect it to vehicle according to
manufacturers directions. (For 2.3L dual
plug engines, use exhaust side plug.
Refer to ignition system section in vehicle
service manual for specific instructions.)
For 1991 & Older Vehicles:
(See page 15 for 1992 & newer
vehicles.)
1) Turn Ignition Key OFF.
• Wait 10 seconds before proceeding.
2) Put Code Scanner HOLD/TEST
Switch in HOLD Position.
WARNING: The next step involves
starting the engine. Observe safety
precautions.
• Always operate vehicle in a well
ventilated area. Do NOT inhale
exhaust gases – they are very
poisonous!
• Set the parking brake.
• Put shift lever in PARK (automatic
transmission) or NEUTRAL (manual
transmission).
• Block the drive wheels.
• Stay away from moving engine parts.
3) Start the Engine.
• If engine will not start, stalls or runs
rough, refer to vehicle service
manual for troubleshooting charts
related to the symptom.
4) Put Code
Scanner
HOLD/TEST
Switch in
TEST
Position.
• The computer is now performing an
Engine Running Self-Test, but do not
be concerned with the test or the
resulting codes at this time. It takes
several seconds before codes are
sent.
5) Wait For End of All Service Code
Signals.
• STO light on Code Scanner stops
blinking.
6) Check Ignition Timing.
• After the last code is sent, the
timing will remain fixed for 2
minutes (unless Self-Test is
deactivated by moving Test/Hold
switch to HOLD position).
• Ignition timing (only during this 2
minute period) should be 20
degrees more than the base timing
value (give or take 3 degrees).
EXAMPLE: If base timing is
specified at 10°, the measured
value in this step should be
10°+20°=30°±3°. That is, the timing
should be in the range of 27° to 33°
BTDC.
• If measured timing does not meet
this specification, refer to vehicle
service manual for procedures to
check base timing and computer
timing advance circuits.
• If measured timing is OK, proceed
to SELF-TEST PART 4: Key On
Engine Running (KOER) Self-Test.
7) Turn Ignition Key to OFF Position.
OFF
AUDIO
ON
CP9015 – Ford, Lincoln & Mercury
Domestic 1981& Newer
TM
®
TEST
ST0
HOLD
S
EL
F
TES
T OU
TP
U
T
