Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Starting System: Description
When the ignition switch is turned to the START position, the Delco-Remy starter solenoid windings are energized. This causes the solenoid plunger to move the shift lever, which engages the pinion with the engine flywheel ring gear. The movement of the plunger also closes the main solenoid contacts, applying battery voltage to the starter motor. See Fig 1.
When the engine starts, the pinion will overrun, protecting the armature from excessive speed and the flywheel from damage. When the ignition switch is released, the plunger return spring disengages the pinion.
On starters with the SD designation, used on 4.3L and 5.0L gasoline engines, the pinion is driven directly by the armature shaft. Wound field coils energize pole pieces that are arranged around the armature.
Starters with the PG designation, used on 5.7L and 7.4L gasoline engines, have a pinion that is driven by a 5:1 gear reduction system. These starters are easily identified by 3 Torx bolts that retain the solenoid. The PG starter should not be disassembled and is serviceable only by complete replacement.
Starters with the 28MT designation, used on diesel engines, have a pinion that is driven by a gear reduction system.
Use the Manual With the Right Hardware
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.
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