Diagnosis Of Starter Motor Noise - GMC G Service Manual

435. Flywheel
436. Pinion
463. Suggested Wire Gage
A. 0.058 mm (0.020-inch) Wire Gage
6.355-12.7mm
" 76.2mm
<1/4"-1/2")
APPROXIMATE

DIAGNOSIS OF STARTER MOTOR NOISE

PROBLEM
High-pitched whine
during cranking
(before engine fires)
but engine cranks
and fires normally.
High-pitched whine
after the engine fires
as key Is being
released. The engine
cranks and fires
normally. This
complaint is often
diagnosed as "starter
hang-in" or "solenoid
weak."
A loud "whoop" after
the engine fires but
while the starter is
still held engaged.
Sounds like a siren if
the engine is rewed
while the starter is
engaged.
A "rumble," "growl"
or (In severe cases) a
"knock" as the starter
is coasting down to a
stop after starting the
engine.
463
436
Figure 34 — Flywheel to Pinion Clearance
POSSIBLE CAUSE
Distance too great between starter pinion
and flywheel.
Distance too small between starter pinion
and flywheel. Flywheel runout contributes to
the intermittent nature of the problem.
Usually due to a worn starter motor clutch.
Usually due to a bent or unbalanced starter
armature.
ENGINE ELECTRICAL 6D-27
463
436
CORRECTION
Remove shims and the starter mount. Refer
to "Starter Motor Noise."
Add shims at the starter mount. Refer to
"Starter Motor Noise."
Remove the starter motor and check the
clutch. Refer to the Light Duty Truck Unit
Repair Manual.
Remove the starter motor and check the ar­
mature. Refer to the Light Duty Truck Unit
Repair Manual.
B-08268
GMTB-0967-2L