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PART 9-1-GENERAL IGNITION SYSTEM SERVICE
9-~
3. With the ignition switch on,
crank the engine and check for
a
spark.
If the spark is good, the trouble
lies in the secondary circuit.
If there is no spark or a weak
spark, the trouble is in the primary
circuit, coil to distributor high ten-
sion lead or the coil.
Primary Circuit. A breakdown or
energy loss in the primary circuit
can be caused by:
1. Defective primary wiring.
2. Burned or improperly adjusted
breaker points.
3. A defective coil.
4. A defective condenser.
Secondary Circuit. A breakdown
or energy loss in the secondary cir-
cuit can be caused by:
1. Fouled or improperly adjusted
spark plugs.
2.
Def~ctive
high tension wiring.
3. High tension leakage across the
coil, distributor cap or rotor.
TRANSISTOR IGNITION
SYSTEM
Do not use any testing proced-
ures or conventional short cuts
other than those listed below, or
extensive damage can result to the
system.
Ignition troubles are caused by a
failure in the primary or secondary
circuit, or incorrect ignition timing.
Isolate the trouble as follows:
1. Remove the coil high tension
lead from the distributor cap.
2. Hold the high tension lead
approximately % inch from the
1
cylinder head or good ground.
3. With the ignition switch on,
crank the engine and check for a
spark. The engine may be cranked
by the conventional method of run-
ning a jumper wire from the battery
positive terminal to the "S" terminal
of the starter relay, after discon-
necting the red and blue lead at
the relay.
If
the spark is good, the trouble
lies in the secondary (high voltage)
circuit. If there is no spark or a
weak spark, the trouble is in the
primary (low voltage) circuit.
Primary Circuit. A breakdown
ot energy loss in the primary circuit
can be caused by:
1. Defective primary wiring.
2. Improperly adjusted, contami-
nated or defective distributor points.
3.
Defective amplifier assembly.
Secondary Circuit.
A
breakdown
or energy loss in the secondary cir-
cuit can be caused by:
1. Fouled or improperly adjusted
spark plugs.
2. Defective high voltage wiring.
3. High voltage leakage across the
coil, distributor cap or rotor.
PRIMARY CIRCUIT TESTS
CONVENTIONAL
IGNITION SYSTEM
A complete test of the primary
circuit consists of checking the cir-
cuit from the battery to the coil, the
circuit from the coil to ground, and
the starting ignition circuit.
Excessive voltage drop in the
primary circuit will reduce the sec-
ondary output of the ignition coil,
resulting in hard starting and poor
performance.
Battery to Coil Test
PROCEDURE
1. Connect the voltmeter leads as
shown in Figs. 4 and 5.
2. Install a jumper wire from the
distributor terminal of the coil to
a good ground on the distributor
housing.
3. Turn the lights and accessories
off.
4. Turn the ignition switch on.
RESULTS. If the voltmeter read-
ing is 6.9 volts or less, the primary
circuit from the battery to the coil
is satisfactory.
FIG.
4-Battery to Coil
Test-Rotunda Tester
82000-A
FIG.
5-BaHery to Coil
Test-Sun Tester
12001-A
If the voltmeter reading is greater
than 6.9 volts, check the following:
1. The battery and cables for loose
connections or corrosion.
2. The primary wiring for worn
insulation, broken strands, and loose
or corroded terminals.
3. The resistance wire for defects.
4. The relay to ignition switch for
defects.
·
Ignition Switch Test
PROCEDURE
1. Connect the voltmeter leads as
shown in Figs. 6 and 7.
2. Install a jumper wire from the
distributor terminal of the coil to a
good ground on the distributor body.
3. Turn all of the accessories and
lights off.
4. Turn the ignition switch on.
RESULTS. If the voltmeter read-
ing is 0.3 volt or less, the ignition
switch and the relay to switch wire
are satisfactory.
If the voltmeter reading is greater
than 0.3 volt, either the ignition
switch and/ or the wire are defective.
Resistance Wire Test
PROCEDURE
1. Connect the voltmeter leads as
shown in Figs. 8 and 9.
2. Install a jumper wire from the
distributor terminal of the coil to a
good ground on the distributor hous-
ing.
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Table of Contents
Troubleshooting
