Operation
STARTING AND CHARGING - V8
DESCRIPTION
Starting
The stalling system on the vehicle comprises a 12 V starter motor which drives the engine to start the combustion process. The starter converts electrical energy into mechanical power. The vehicle electrical system must be capable of supplying sufficient power to enable the engine to be cranked.
Range Rover features 'lazy starting'. This entails the driver not having to hold the ignition key in the 'crank position'. Starting of the engine is controlled automatically by the Engine Control Module (ECM), which provides power to the starter motor until engine speed is greater than 920 rpm (engine cold) or 680 rpm (engine warm).
Charging
The charging system comprises a battery and an alternator. The battery must be of a sufficient capacity to operate the starter motor and operate the various electrical systems in the vehicle. The alternator charges the battery when the engine is running and increases its output as demand on the battery increases.
CAUTION: The battery positive terminal uses a pyrotechnic attachment which detaches the battery cable in the event of a crash severe enough to trigger the airbags.
The alternator is located at the front LH side of the engine. The alternator has an output of 90/150 Amps and is manufactured by Bosch. A polyvee belt drives the alternator pulley, which in turn is driven from the engine crankshaft pulley.
The instrument pack incorporates a charge warning lamp which illuminates when there is no output or a low output from the alternator.
OPERATION
Power Distribution
Feed from the positive battery terminal (C0192) is supplied to fuse 25 and fuse 53 of the passenger compartment fuse box (C0632) on an R wire. Fuse 53 (C0583) is connected to the ignition switch (C0028) by an RU wire. When the ignition switch is turned to the 'ignition' position, current flows across the switch (C0028) to fuse 5 of the passenger compartment fuse box (C0585) on a G wire. Fuse 5 (C0587) provides an ignition feed to the alternator (C0053) on a GW wire.
Fuse 25 of the passenger compartment fuse box (C0583) is connected to the ignition switch (C0028) by an R wire. When the ignition switch is turned to the 'crank' position, current flows across the switch (C0028) to the Engine Control Module (ECM) (C0331) on a BY wire, and the ignition coil relay (C2089) on a G then GN wire.
Starting
Starter Motor
The starter motor solenoid (C0178) is provided a constant battery feed from the battery (C0192) on an R wire. If all parameters for starting have been met, the ECM (C0331) provides a feed to the automatic transmission interlock relay (C1455) on a YN wire. If the gear selector lever is in 'Park' or 'Neutral', the interlock relay (C1455) provides a feed to the starter solenoid (C0179) on a B then BY wire. The energised starter solenoid allows the battery feed to power the starter motor.
The starter motor (C0179) also provides an 'engine start' signal back to the ECM (C0606) on a BG wire.
Ignition Coils
The ignition coil relay (C2089) receives an 'engine crank' feed from the ignition switch (C0028) on a GN wire. The relay coil (C2089) is earthed on an N wire. The energised ignition coil relay (C2089) provides a feed to the following on G wires:
- Ignition coil 1 (C0156).
- Ignition coil 2 (C0052).
- Ignition coil 3 (C0276).
- Ignition coil 4 (C3770).
- Ignition coil 5 (C1771).
- Ignition coil 6 (C1772).
- Ignition coil 7 (C2087).
- Ignition coil 8 (C2088).
Fuel Pump
When the engine is started, the ECM (C0331) provides an earth path for the fuel pump relay coil (C2022) on a BP wire. The energised fuel pump relay (C2020) provides a feed to the fuel pump (C0114) on a WU wire. The fuel pump (C0114) is earthed on an N wire.
Charging
The battery (C0192) provides a permanent feed to the alternator (C0183) on an R wire. Fuse 5 of the passenger compartment fuse box (C0587) provides an ignition feed to the alternator (C0053) on a GW wire.
When the engine is cranked, the alternator (C0053) supplies the ECM (C0606) a Pulse Width Modulated (PWM) signal on a U wire. The ECM uses this PWM signal to calculate the electrical load on the alternator, and controls engine idle speed accordingly.
When the engine is started, the magnetized rotor within the stator windings generate 3 phase alternating current (ac) and voltage that rises rapidly with rotor speed. The field diodes in the rectifier pack convert the ac current into direct current (dc). Output current from the field diodes supplements the initial current flowing through the field windings. This causes an increase in the magnetic influence of the rotor, resulting in self-exitation of the alternator. The field current increases with rotor speed and thus increases the generated current and voltage until the alternator is fully excited. The alternator (C0183) charges the battery (C0192) by providing current on an R wire.