TROUBLESHOOTING 31 3. Hold a vibration-type tachometer against the starter frame. 4. To operate the starter motor, connect a wire between the positive battery terminal and the S terminal on the starter solenoid. 5. Note the starter rpm, current draw and battery voltage while the motor is running, then disconnect the wire to the S terminal on the solenoid. 6. Ifthe starter motor does not perform within the specifi- cations listed in Table 3, repair or replace the motor as de- scribed in Chapter Nine. 3. Charging system warning lamp flashes on and ofJ- This usually indicates that the charging system is working intermittently.
Check drive belt tension first, then check all electrical connections in the charging circuit. As a last resort, check the alternator. 4. Charging system warning lamp comes on and stays on-This usually indicates that no charging is taking place. First check drive belt tension, then the battery con- dition. Check all wiring connections in the charging sys- tem. If this does not locate the problem, check the alternator and voltage regulator as described in this chap- ter. 5. Battery requiresfrequent addition of water or lamp re- quires frequent replacement-The alternator is probably overcharging the battery. The voltage regulator is most likely at fault. 6.
Excessive noise from the alternator-Check for loose mounting brackets and bolts. The problem may also be worn bearings or, in some cases, lack of lubrication. If an alternator whines, a shorted diode may be the problem. CHARGING SYSTEM The charging system consists of the alternator, voltage regulator, battery, key switch, instrument panel warning light, connecting wiring and fuse. A belt driven by the engine crankshaft pulley turns the alternator, which produces electrical energy to charge the battery. As engine speed varies, the voltage output of the alternator varies. The regulator maintains the voltage to the electrical system within safe limits.
The warning light on the instrument panel signals if charging is not taking place. All models use a Hitachi alternator with an internal transistorized voltage regulator attached to the rear alter- nator housing. Alternator output is 35 amps (model LR135-05) or 55 amps (model LRI55-20). Figure 5 shows components of the charging circuit. Charging system troubles are generally caused by a de- fective alternator, voltage regulator, battery or an inopera- tive charge lamp. They may also be caused by something as simple as incorrect drive belt tension. The following are symptoms of problems that may be encountered. I.
Battery discharges frequently-This can be caused by a drive belt that is slightly loose. Grasp the alternator pul- ley with both hands and try to tum it. If the pulley can be turned without moving the belt, the drive belt is too loose. As a rule, keep the belt tight enough so that it can be de- flected only about 1/2 in. under moderate thumb pressure applied between the pulleys. The battery may also be at fault; test the battery condition as described in Chapter Nine. 2. Charging system warning lamp does not light when key switch is turned ON-This may indicate a defective key switch, battery, voltage regulator or warning lamp. Try to start the engine.
If it doesn't start, check the key switch and battery. Ifthe engine starts, remove and test the warning lamp bulb. If the problem persists, the alternator brushes may not be making contact. Perform the System Circuitry Test in this chapter. CHARGING SYSTEM TESTS The alternator is equipped with an internal transistor- ized regulator. The transistorized regulator contains exci- tation and sensing circuits. The regulator controls output voltage by switching the alternator rotor current on and off. A rectifier consisting of a set of diodes converts alter- nating current to direct current. Alternator Regulated Voltage Test This test checks the regulated voltage output of the al- ternator.
All wires connected to the alternator for normal operation must be connected. I. Check the alternator drive belt tension. See Chapter Three. 2. Check the battery terminals and cables for corrosion and/or loose connections. Disconnect the negative battery cable, then the positive battery cable. Clean the cable clamps and battery terminals, if necessary, then reconnect the cables. 3. Check all wiring connections between the alternator and engine to make sure they are clean and tight. 4. Connect the positive lead of a voltmeter to the BAT ter- minal of the alternator. Connect the negative voltmeter lead to the E terminal of the alternator. See Figure 6. 5.
Move the engine wire harness back and forth while ob- serving the voltmeter scale. The meter should indicate a steady battery voltage reading (approximately 12 volts).