Starting System: Description and Operation

STARTER SYSTEM
The function of the starting system is to crank the engine at a sufficient speed to allow it to start. Heavy gauge cables, connectors, and switches are used in the starting system because of the large amount of electrical current required by the starter motor while cranking the engine. The amount of resistance in the starting circuit must be kept to a minimum to provide the maximum current for the starter operation. A discharged or damaged battery, loose or corroded connections, or partially broken cables will result in slower than normal cranking speeds, and may also prevent the starter motor from cranking the engine.

If the starter motor or starting circuit is suspected to be the cause of a no-start condition, use the Symptom Chart and diagnostic tests to isolate the condition. Testing and Inspection

The starting system includes the following:
- Starter motor
- Starter solenoid
- Battery
- Ignition switch
- Transmission Range (TR) switch
- Heavy circuit wiring







Sequence of Operation
When the starter solenoid is energized, a magnetic field is created in the starter solenoid windings. The iron plunger core is drawn into the solenoid coil, and the drive lever and pin connected to the starter drive engages the flywheel ring gear. When the plunger is pulled all the way in, its contact disk closes the circuit between the battery and starter motor feed terminals. This sends current to the starter motor, and the starter drive cranks the flywheel to start the engine. When current flows to the starter motor, the solenoid pull-in coil is bypassed, and the hold-in coil keeps the starter drive engaged with the flywheel until the ignition switch is released from the START position.

The starter drive protects the starter motor from excessive speeds during the brief period before the driver releases the ignition switch from the START position.

A Park/Neutral Position (PNP) switch circuit within the Transmission Range (TR) switch senses when the gearshift lever is in the NEUTRAL (N) or PARK (P) position and completes the starter motor circuit.

The starter motor uses a planetary gear reduction system to reduce internal torque.