Jeep Engines - Oljeep

- -'7INTRODUCTIONThe starting system is designed to provide the vehicleoperator with a convenient, efficient and reliable means ofcranking and starting the internal combustion engine used topower the vehicle and all of its accessory systems from withinthe safe and secure confines of the passenger compartment.The starting system consists of the following components:BatteryStarter relayStarter motor (including an integral starter solenoid)Ignition switch0 Parkheutral position switchWire harnesses and connections (including the batterycables).OperationThe starting system components form two separate circuits.A high-amperage feed circuit that feeds the starter motorbetween 150 and 350 amperes, and a low-amperage controlcircuit that operates on less than 20 amperes. The highamperagefeed circuit components include the battery,battery cables, the contact disc portion of the startersolenoid, and the starter motor. The low-amperage controlcircuit components include the ignition switch, theparWneutra1 position switch, the starter relay, theelectromagnetic windings of the starter solenoid, and theconnecting wire harness components.Battery voltage is supplied through the low-amperagecontrol circuit to the coil battery terminal of the starter relaywhen the ignition switch is turned to the momentary Startposition. The parkheutral position switch is installed inseries between the starter relay coil ground terminal andground. This normally open switch prevents the starterrelay from being energized and the starter motor fromoperating unless the automatic transmission gear selector isin the Neutral or Park positions.When the starter relay coil is energized, the normally openrelay contacts close. The relay contacts connect the relaycommon feed terminal to the relay normally openterminal. The closed relay contacts energize the startersolenoid coil windings.The energized solenoid pull-in coil pulls in the solenoidplunger. The solenoid plunger pulls the shift lever in thestarter motor. This engages the starter overrunning clutchand pinion gear with the starter ring gear on the automatictransmission torque converter drive plate.4.0L POWER TECH IN-LINE 6 (STARTING SYSTEM) 247Starting SystemAs the solenoid plunger reaches the end of its travel, thesolenoid contact disc completes the high-amperage starterfeed circuit and energizes the solenoid plunger hold-in coil.Current now flows between the solenoid battery terminaland the starter motor, energizing the starter.Once the engine starts, the overrunning clutch protects thestarter motor from damage by allowing the starter piniongear to spin faster than the pinion shaft. When the driverreleases the ignition switch to the On position, the starterrelay coil is de-energized. This causes the relay contacts toopen. When the relay contacts open, the starter solenoidplunger hold-in coil is de-energized.When the solenoid plunger hold-in coil is de-energized, thesolenoid plunger return spring returns the plunger to itsrelaxed position. This causes the contact disc to open thestarter feed circuit, and the shift lever to disengage theoverrunning clutch and pinion gear from the starter ring gear.Following are general descriptions of the majorcomponents in the starting system.STARTER MOTOR(Refer to Figure 4-52.)The starter motor incorporates several features to create areliable, efficient, compact, lightweight and powerful unit.The electric motor of the starter features fourelectromagnetic field coils wound around four pole shoes,and four brushes contact the motor commutator. The startermotor is rated at 1.4 kilowatts (about 1.9 horsepower)output at 12 volts.The starter motor is serviced only as a unit with its startersolenoid and cannot be repaired. If either component isfaulty or damaged, the entire starter motor and startersolenoid unit must be replaced.OperationThe starter motor is equipped with a planetary gearreduction (intermediate transmission) system. Theplanetary gear reduction system consists of a gear that isintegral to the output end of the electric motor armatureshaft that is in continual engagement with a larger gear thatis splined to the input end of the starter pinion gear shaft.This feature makes it possible to reduce the dimensions ofthe starter. At the same time, it allows higher armaturerotational speed and delivers increased torque through thestarter pinion gear to the starter ring gear.