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9-4
GROUP
9-
IGNITION SYSTEM
cuit consists of checking the circuit
from the battery to the coil, the cir-
cuit from the coil to ground, and the
starting ignition circuit.
Excessive voltage drop in the pri-
mary circuit will reduce the second-
ary output of the ignition coil, result-
ing in hard starting and poor per-
formance.
Battery to Coli Test
1. Connect the voltmeter leads as
shown in Fig. 2.
2. Install a jumper wire from the
distributor terminal of the coil to a
good ground on the distributor hous-
ing.
3. Turn the lights and accessories
off.
4. Turn the ignition switch
on.
5. If the voltmeter reading is 6.9
volts or less, the primary circuit
from the battery to the coil is satis-
factory.
6. If the voltmeter reading is
greater than 6.9 volts, check the fol-
lowing:
The battery and cables for loose
connections or corrosion.
The primary wiring for worn insu-
lation, broken strands, and loose or
corroded
terminals.
The resistance wire for defects.
The starter relay to ignition switch
for defects.
Starting Ignition Circuit Test
1. Connect the voltmeter leads as
shown in Fig. 2.
l. Disconnect and ground the coil
to distributor high tension lead at the
distributor.
3. With the ignition switch off,
crank the engine by installing a jump-
er wire between the battery and the
"S" terminal of the starter relay while
observing the voltage drop.
4. If the voltage drop is 0.1 volt
or less, the starting ignition circuit is
satisfactory.
5. If the voltage drop is greater
than 0.1 volt, clean and tighten the
terminals in the circuit or replace the
wiring as necessary.
Ignition Switch Test
1. Connect the voltmeter leads as
shown
in
Fig. 3.
l. 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.
5. If the voltmeter reading is 0.3
volt or less, the ignition switch and
the relay to switch wire are satisfac-
tory.
6. If the voltmeter reading is
greater than 0.3 volt, either the ig-
nition switch and/ or the wire are de-
fective.
Resistance Wire Test
1. Connect the voltmeter leads as
shown
in
Fig. 4.
l. Install a jumper wire from the
distributor terminal of the coil to a
good ground on the distributor hous-
ing.
3. Turn all of the accessories and
lights off.
4. Tum the ignition switch on.
5. If the voltmeter reading is 6.6
volts or less, the resistance wire is
satisfactory.
6. If the voltmeter reading is
greater than 6.6 volts, replace the re-
sistance wire.
Coli to Ground Test
1. Connect the voltmeter leads as
shown
in
Fig. 5.
l.
Close the breaker points.
3. Turn all lights and accessories
off.
4. Turn the ignition switch on.
5. If
the voltmeter reading is 0.1
volt or Jess, the primary circuit from
coil to ground is satisfactory.
6. If the voltmeter reading is
greater than 0.1 volt, test the voltage
drop between each of the following:
The coil and breaker point termi-
nals of the coil to distributor primary
wire.
The movable breaker point and the
breaker plate.
The breaker plate and the distri-
butor housing.
The distributor housing and engine
ground.
Breaker Points
Clean and inspect the breaker
points by following the procedure un-
der Cleaning and Inspection (Section
3 of this part).
The breaker point dwell can be
checked with a distributor tester or a
dwell meter by following the proce-
dure under Distributor Tests in this
section of the manual.
The breaker p"int resistance can
be checked with
;_
distributor tester
by following the procedure under
Distributor Tests
in
this section of
the manual.
Coli
Clean and inspect the coil by fol-
lowing the procedure under Cleaning
and Inspection (Section 3 of this
part).
Check the coil on a coil tester by
following the manufacturers instruc-
tions.
SECONDARY CIRCUIT TESTS
Distributor Cap
Clean and inspect the distributor
cap by following the procedure under
Cleaning and Inspection (Section 3 of
this part).
Rotor
Clean and inspect the rotor by fol-
lowing the procedure under Cleaning
and Inspection (Section 3 of this
part).
Secondary (High Tension)
Wires
The secondary wires include the
wires connecting the distributor cap
to the spark plugs and the wire con-
necting the center terminal of the
distributor cap to the center terminal
of the ignition coil.
Clean and inspect the secondary
wiring by following the procedure
under Cleaning and Inspection (Sec-
tion 3 of this part).
These wires are the radio resist-
ance-type which filter out the high
frequency electrical impulses that
are the source of ignition noise inter-
ference. The resistance of each wire
should not exceed 7000 ohms per
foot.
When checking the resistance of
the wires or setdng lpltion timing,
do not puncture the
wires
with a
probe. The probe may cause a sep·
aratioa In the conductor.
When removing the wires from the
spark plugs,
grasp
and
twist
the
moulded cap, then puB the cap off
the spark plug. Do not pull on the
wire
because the
wire
connection Ia·
ade the cap may become separated
or the Insulator seal may be dam·
aged.
To check the.spark intensity at the
spark plugs, proceed as follows:
1. Disconnect a spark plug
wire.
Check the spark Intensity of one
wire
at a time.
2. Install a terminal adapter in the
terminal of the wire to be
checked.
Hold the adapter approximately 3fw
inch from the exhaust manifold and
crank the
·
engine, using a remote
starter switch. The spark should jump
the gap regularly.
3. If the spark intensity of all the
wires is satisfactory, the
coil,
con-
denser, rotor, distributor cap and the
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