106991-1912 ZEXEL 9 400 612 290 BOSCH INJECTION-PUMP ASSEMBLY 9400612290 1069911912 1156031922

Fuel Pressure Input Circuit
Fuel pressure is monitored after the filter by the fuel pressure sensor which is located on the fuel filter housing. The 5 Volt DC operating voltage for this sensor is supplied by the ECM. The output of the fuel pressure sensor is a .5 to 4.5 Volts DC signal. The voltage is dependent upon fuel pressure and is interpreted by the ECM as fuel pressure. If fuel pressure is less than 445 kPa (65 psi) at rated rpm, the "check engine" light is turned on.Engine Electrical System
The electrical system can have three separate circuits: the charging circuit, the starting circuit and the low amperage circuit. Some of the electrical system components are used in more than one circuit. The battery (batteries), circuit breaker, ammeter, cables and wires from the battery are all common in each of the circuits.The charging circuit is in operation when the engine is running. An alternator makes electricity for the charging circuit. A voltage regulator in the circuit controls the electrical output to keep the battery at full charge.The starting circuit is in operation only when the start switch is activated.The low amperage circuit and the charging circuit are both connected through the ammeter. The starting circuit is not connected through the ammeter.Charging System Components
Alternator
The alternator is driven by 2 vee belts from the crankshaft pulley. This alternator is a three phase, self-rectifying charging unit, and the regulator is part of the alternator.This alternator design has no need for slip rings or brushes, and the only part that has movement is the rotor assembly. All conductors that carry current are stationary. The conductors are: the field winding, stator windings, six rectifying diodes, and the regulator circuit components.The rotor assembly has many magnetic poles like fingers with air space between each opposite pole. The poles have residual magnetism (like permanent magnets) that produce a small amount of magnet-like lines of force (magnetic field) between the poles. As the rotor assembly begins to turn between the field winding and the stator windings, a small amount of alternating current (AC) is produced in the stator windings from the small magnetic lines of force made by the residual magnetism of the poles. This AC current is changed to direct current (DC) when it passes through the diodes of the rectifier bridge. Most of this current goes to charge the battery and to supply the low amperage circuit, and the remainder is sent on to the field windings. The DC current flow through the field windings (wires around an iron core) now increases the strength of the magnetic lines of force. These stronger lines of force now increase the amount of AC current produced in the stator windings. The increased speed of the rotor assembly also increases the current and voltage output of the alternator.The voltage regulator is a solid state (transistor, stationary parts) electronic switch. It feels the voltage in the system and switches on and off many times a second to control the field