Starter Motor - Service Manual Supplemental Information: Description and Operation
The function of the starting system is to crank the engine at a speed fast enough to permit the engine to start. Heavy cables, connectors, and switches are used in the starting system because of the large current required by the starter while it is cranking the engine. The amount of resistance in the starting circuit must be kept to an absolute minimum to provide maximum current for 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 even prevent the starter from cranking the engine.
In case of starting system trouble, the operator may have discharged the battery before calling for assistance. A road service procedure is presented to aid the service technician in such cases of starting trouble. Be sure to follow diagnosis procedures in the Engine/Emissions Diagnosis Manual*, in order to locate the cause of the starting difficulty. Road service is not a part of the diagnosis procedures.
The starting system includes the permanent magnet gear-reduction starter with a solenoid-actuated drive, the battery, a remote control starter switch (part of the ignition switch), the neutral start switch (automatic transmission or transaxle), clutch switch (manual transmission or transaxle), the starter relay, and heavy circuit wiring.
28-07-2 Starter Motor-Gear Reduced Permanent Magnet
DESCRIPTION AND OPERATION (Continued)
Turning the ignition switch to the START position actuates the starter relay, through the starter control circuit. The starter relay then connects the battery to the starter solenoid, causing it to energize.
Vehicles equipped with a manual transmission or transaxle have a clutch switch in the starter circuit which prevents operation of the starter unless the clutch pedal is depressed.
Vehicles equipped with an automatic transmission or transaxle have a neutral start switch in the starter control circuit, which prevents operation of the starter unless the selector lever is in the NEUTRAL or PARK position.
When the starter solenoid is energized, a magnetic field is created in the solenoid windings. The iron plunger core is drawn into the solenoid coil and a lever connected to the drive assembly engages the drive pinion gear into the flywheel ring gear. When the plunger is pulled all the way in, its contact disk closes the circuit between the battery and motor feed terminals. This sends current to the motor and the drive pinion gear cranks the flywheel to start the engine. When current flows to the motor, the solenoid energizing coil is bypassed and the holding coil keeps the drive pinion gear engaged with the flywheel until the ignition switch is released from the START position.
An overrunning clutch in the drive assembly protects the starter from excessive speeds during the brief period before the driver releases the ignition switch from the START position (as the engine starts).