GMC 1976 ZEO 6083 Maintenance Manual page 442

6Y- 62 ENGINE ELECTRICAL
STARTER SOLENOID OR STARTER CANNOT
BE HEARD WHEN KEY IS IN START POSITION
(Parking Brake Must Be Fully Applied During Test)
Check for dirty or poor connection(s)
at battery, solenoid and engine ground
strap .
CONNECTION(S) POOR
1 . Connect voltmeter between purple wire
terminal on solenoid and starter housing .
2 . Turn key to "Start" and observe voltmeter oscillation .
LOWEST READING
BELOW 7 VOLTS
Check for dirty or poor connections
at battery, solenoid and engine ground
strap .
1 . Make sure connections are good at
neutral or clutch start switch .
2 . Turn on headlamps, turn ignition
switch to "Start" .
STARTER STILL DOES
NOT OPERATE
Check purple wire from switch
to starter, if OK, remove starter
for repair .
SOLENOID PUMPS IN AND OUT
Make Sure Selector Is In "Neutral" Or "Park"
And Parking Brake Fully Applied
STARTING CIRCUIT DIAGNOSIS
Check condition and
state of charge of
battery .
BATTERY GOOD
LAMPS BRIGHT
1
Disconnect the two purple
wires from neutral start switch .
2 . Connect a jumper wire between
the two wires in connector .
3 . Turn ignition switch to "Start" .
LOWEST READING
7 VOLTS OR MORE
If all wiring and
connections are good
disconnect negative
battery cable from
battery .
Remove test and repair
starter .
STARTER NOW
OPERATES
Replace neutral start switch .
2 .
STARTER STOPS
SOLENOID CLICKS ONCE OR TWICE BUT STARTER
DOES NOT TURN OR TURNS TOO SLOW
CONNECTIONS GOOD
Check condition and state of
charge of battery .
BATTERY GOOD
Check for proper weight
oil .
Connect red voltmeter
lead to positive cable
at battery, black lead
to battery cable terminal
of starter .
Crank engine and observe
voltage .
LESS THAN
0 .5 VOLTS
1 . Connect voltmeter black
lead to battery negative
post and red lead to starter
case .
2 . Crank engine and observe
voltage .
MORE THAN 0 .2 VOLTS
Clean battery ground cable at
both ends or replace cable as
required .
Replace ignition switch
(key lock, linkage or
ignition switch on column
mounted units) .
Check for dirty or poor connection(s)
at battery, solenoid and engine ground
strap .
Turn ey to "Off
.
1 . Disconnect negative battery cable from
battery .
2 . Remove, test and repair starter .
3 . Examine ring gear for damage .
CONNECTIONS POOR
Clean, tighten, or replace
as necessary .
BATTERY BAD
Recharge or replace as
necessary .
OIL T00 THICK
Drain and refill
with recommended
weight .
LESS THAN 0 .2 VOLTS
Remove, test and repair
starter .
STARTER KEEPS RUNNING AFTER KEY IS RELEASED
FROM "START" TO "RUN" POSITION
STARTER KEEPS RUNNING
STARTER SPINS AND/OR MAKES LOUD GRINDING
NOISE BUT DOES NOT TURN ENGINE
1 . Disconnect negative battery cable from
battery .
2 . Remove test and repair starter .
Starting Circuit Diagnosis
2 . Check condition and state of charge of
battery .
1 .
BATTERY BAD
BATTERY GOOD
'
Recharge or replace as
2 .
necessary .