Actron AutoTroubleShooter CP7677 - Manual (Page 21)

21
Ignition System Wires
This test measures the resistance
of spark plug and coil tower wires
while they are being flexed. This
test can be used for distributorless
ignition systems (DIS) provided the
system does not mount the ignition
coil directly on the spark plug.
Test Procedure:
1. Remove ignition system wires
one at a time from engine.
• Always grasp ignition system
wires on the boot when re-
moving.
• Twist the boots about a half turn
while pulling gently to remove them.
• Refer to vehicle service manual for
ignition wire removal procedure.
• Inspect ignition wires for cracks,
chaffed insulation, and corroded
ends.
NOTE: Some Chrysler products use
a “positive-locking” terminal electrode
spark plug wire. These wires can
only be removed from inside the dis-
tributor cap. Damage may result if
other means of removal are at-
tempted. Refer to vehicle service
manual for procedure.
NOTE: Some spark plug wires have
sheet metal jackets with the follow-
ing symbol:
. This type of plug
wire contains an “air gap” resistor
and can only be checked with an
oscilloscope.
2. Insert BLACK test lead into COM
test lead jack (see Fig. 26).
3. I n s e r t R E D t e s t l e a d i n t o
test lead jack.
4. Connect RED test lead to one end
of ignition wire and BLACK test
lead to other end.
5. Turn multimeter rotary switch to
200K
Ω
range.
6. View reading on display while flex-
ing ignition wire and boot in sev-
eral places.
• Typical resistance range is 3K
Ω
to
50K
Ω
or approximately 10K
Ω
per
foot of wire.
• Refer to vehicle service manual
for your vehicles resistance range.
• As you flex ignition wire, the dis-
play should remain steady.
7. Test Results
Good Ignition Wire: Display reading
is within manufacturers specifica-
tion and remains steady while wire
is flexed.
Bad Ignition Wire: Display reading
erratically changes as ignition wire
is flexed or display reading is not
within manufacturers specification.
Fig. 26
Black
Spark Plug Wire
Red