Service Procedures; Checks And Adjustments On Car - Pontiac FIREBIRD 1972 Service Manual

6E-6 1972 PONTIAC SERVICE MANUAL
force in the first movement of the clutch along the arma-
ture shaft. A pinion stop, consisting of a snap ring and
retainer and a thrust collar assembled on the armature
shaft, takes all the end thrust. The flange mounted solen-
oid switch operates the overrunning clutch drive by means
of a linkage to the shift lever.
Following is a description of the operation of the solenoid
used on all models. There are two coil windings in the
solenoid: a pull-in winding and a hold-in winding (Fig.
6E-1). Both windings are energized when the ignition
switch is closed. They produce a magnetic field which
pulls the plunger in so that the drive pinion is shifted into
-
mesh, and the main contacts in the solenoid switch are
closed to connect the battery directly to the cranking mo-
tor. Closing of the main switch contacts shorts out the
pull-in winding since this winding is connected across the
main contacts. The magnetism produced by the hold-in
winding is sufficient to hold the plunger in, and shorting
out the pull-in winding reduces drain on the battery.
When the ignition switch is opened, it disconnects the
hold-in winding from the battery; the shift lever spring
withdraws the plunger from the solenoid, opening the
solenoid switch contacts and at the same time withdraw-
ing the drive pinion from mesh.
SERVICE PROCEDURES
PERIODIC SERVICE
No periodic lubrication of the starting motor or solenoid ble at the switch terminal of the solenoid. If the solen-
is required. The motor and brushes cannot be inspected
oid does not feel warm, it should pull in whenever the
without disassembling the unit, so no service is required voltage available at the switch terminal is 7.7 volts or
on the motor or solenoid between overhaul periods. more (when the solenoid feels warm, it will require a
somewhat higher voltage to pull in).
CHECKS AND ADJUSTMENTS ON CAR
Although the starting motor cannot be checked against
OVERHAUL PROCEDURES
specifications on the car, a check can be made for exces-
sive resistance in the cranking circuit by measuring:
REMOVE FROM CAR
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6-CYL. ENGINE
The voltage drop, during cranking, between the posi-
tive battery post and battery terminal of solenoid.
The voltage drop, during cranking, between the bat-
tery terminal of solenoid and the motor terminal of
solenoid.
The voltage drop, during cranking, between the nega-
tive battery post and the starting motor frame.
CAUTION: To prevent the engine from finng
during the above checks, disconnect the pri-
mary lead to the distributor at the coil.
If the voltage drop for any one of the above three
checks exceeds 0.2 volt, excessive resistance is in-
dicated in that portion of the cranking circuit being
checked. Locate and eliminate the cause for any
excessive voltage drop in these circuits in order to
obtain maximum efficiency of the cranking system.
When the solenoid fails to pull in, the trouble may be
due to excessive voltage drop in the solenoid control
circuit. To check for this condition, close the starting
switch and measure the voltage drop between the
battery terminal of the solenoid and the switch termi-
nal of the solenoid. Excessive resistance in the solen-
oid control circuit is indicated and should be
corrected if the voltage drop exceeds 3.5 volts.
If the voltage drop does not exceed 3.5 volts and the
solenoid does not pull in, measure the voltage availa-
1. Disconnect positive battery cable at battery terminal
post.
2. Disconnect battery positive cable and wiring harness
leads from starting motor solenoid.
3. Disconnect starter motor brace and swing out of way.
4. Remove starter motor to engine thru bolts and
remove starter.
REMOVE FROM CAR
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V-8 ENGINE
1. Disconnect positive battery cable from battery.
2. Raise car.
3. Disconnect starter motor brace and swing forward
out of way.
4. Remove two starter motor thru bolts and let starter
motor swing down and hang by wires.
5. Remove solenoid wires and battery cable and remove
starter.
SOLENOID
REMOVE AND REPLACE