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ELECTRICAL SYSTEM 14-41
Ignition System
Ignition Coil Inspection
Measuring arcing distance
The most accurate test for determining the condition of
the ignition coil is made by measuring arcing distance.
•
Remove the ignition coil (see Ignition Coil Removal).
•
Connect the ignition coil [A] (with the spark plug cap left
installed on the spark plug lead) to the tester [B], and mea-
sure the arcing distance.
Auxiliary Wires [C]
WARNING
To avoid extremely high voltage shocks, do not
touch the coil or lead.
If the distance reading is less than the specified value, the
ignition coil or spark plug cap is defective.
3 Needle Arcing Distance
Standard: 7 mm (0.28 in.) or more
•
To determine which part is defective, measure the arcing
distance again with the spark plug leads removed from
the ignition coil (see Ignition Coil Removal).
If the arcing distance is subnormal as before, the trouble
is with the ignition coil itself. If the arcing distance is now
normal, the trouble is with the spark plug lead.
Measuring coil resistance
If the Coil Tester is not available, the coil can be checked
for a broken or badly shorted winding with a hand tester.
However, a hand tester can not detect layer shorts and
shorts resulting from insulation breakdown under high volt-
age.
•
Disconnect the primary leads from the coil terminals.
•
Measure the primary winding resistance as follows [A].
○
Connect the tester between the coil terminals.
○
Set the tester to the × 1 Ω range, and read the tester.
•
Measure the secondary winding resistance as follows [B].
○
Remove the spark plug leads (see Ignition Coil Removal).
○
Connect the tester between the secondary lead terminals.
○
Set the tester to the × 1 kΩ, and read the tester.
If the hand tester does not read as specified, replace the
coil.
Winding Resistance
Standard: Primary windings 1.53 ∼ 2.07 Ω
Secondary windings 12.50 ∼ 16.91 kΩ
If the tester reads are as specified, the ignition coil wind-
ings are probably good. However, if the ignition system
still does not perform as it should after all other compo-
nents have been checked, test replace the coil with one
known to be good.