Chevrolet 70 1969 Series, Руководство по ремонту

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ENGINE ELECTRICAL 6Y-8
If voltmeter reading in any of the above checks
exceeds 0.5 volt, excessive resistance is indicated
in that part of the circuit being checked. Locate
and eliminate the cause of excessive voltage drop
in these circuits in order to obtain maximum effic­
iency from the starting system. Cause of excessive
resistance may be loose, corroded, or dirty con­
nections, or frayed cables.
If starter fails to crank engine, first make
sure battery is not discharged, then check solenoid
or magnetic switch operation. If the solenoid fails
to operate, the trouble may be due to excessive
resistance in the starter control circuit. Check all
wiring and connections from ignition or control
switch to solenoid for loose or corroded connec­
tions. If the cause of excessive resistance is not
apparent, connect a short jumper lead across the
solenoid battery and switch terminals. If solenoid
operates with jumper lead connected, trouble is in
the control circuit. Check for defective ignition or
control switch. If solenoid does not operate with
jumper lead connected, solenoid or magnetic switch
is defective and must be replaced.
STARTER REPLACEMENT
R E M O V A L
1. Remove ground strap from battery negative
(-) post or tape end of battery cable when discon­
nected from starter solenoid to prevent discharge
of battery by direct short.
2. Disconnect all wires from starter solenoid
terminals.
3. Remove bolts, nuts, and washers attaching
starter to flywheel housing and pull starter for­
ward to remove.
IN S T A L L A T IO N
1. Position starter against flywheel housing
and secure with bolts, nuts, and washers. Tighten
Figure 2— Starter Automatic Disengagement
and Lock-Out (Series “53 ” and Diesel) (Typical)
starter to flywheel housing mounting bolts or nuts
to torque recommended in "Specifications" at end
of this section.
2. Connect all wires to starter solenoid term­
inals referring to applicable Wiring Diagrams
in Section 12 to make sure of proper connections.
Tighten terminal nuts firmly.
3. Connect ground strap to battery negative
(-) post.
STARTER AUTOMATIC
DISENGAGEMENT AN D LOCK OUT
A starter automatic disengagement and lock­
out system is used on all series " 5 3 ” Diesel
engine models.
This system is used to prevent starter over­
speeding by breaking circuit between the battery
and starter solenoid after engine is started and to
prevent the starter pinion from engaging a running
flywheel by keeping the battery-to-starter solenoid
circuit open while the engine is running. With the
battery-to-starter solenoid circuit broken, the
starter will automatically disengage if control
switch is not released after the engine is started.
SERIES “ 53” D IE S E L EN GINES
A typical system used on vehicles equipped
with the series " 5 3 ” Diesel engine is shown in
Figure 2. When the control switch is turned to
" S T A R T ” position, current from the battery will
flow through the control switch and starter mag­
netic switch coil windings to ground through the
engine fuel pressure switch.
N O T E : A diode is spliced into the engine
wiring harness (fig. 2) to protect the fuel pressure
switch contacts.
With the starter magnetic switch coil winding
energized, switch contacts will close to complete
circuit to starter solenoid. With solenoid energized,
starter will operate. Wnen engine is started, the
fuel pressure switch contacts will open to break
ground circuit to the starter magnetic switch. The
starter magnetic switch contacts will then open to
break circuit between the battery and starter sole­
noid.
PINION CLEARANCE CHECK
L IG H T A N D IN T E R M E D IA T E D U T Y
1. The drive pinion clearance should be check­
ed whenever starter has been overhauled. There
is no means of adjusting the pinion clearance on the
light duty starting motors. If clearance is not with­
in specified limits, it may indicate excessive wear
of the solenoid linkage or shift lever yoke lugs.
CHEVROLET SERIES 7 0 -8 0 H EAVY DUTY TRUCK SH O P M A N U A L