Electrical/electronic circuit

ELECTRICAL/ELECTRONIC CIRCUIT

This circuit electrically connects all the components of the system and is made up of the following components:

• wiring with fuses;
• HITACHI engine control unit;
• system and pump relay;
• sensors:
  butterfly position sensor,
  coolant temperature sensor,
  air flow meter,
  engine rpm sensor,
  engine timing sensor,
  Lambda sensor,
  vehicle speed sensor,
  detonation sensor;

• actuators:
  electric fuel pump,
  injectors,
  engine idle speed adjustment solenoid valve,
  charcoal filter solenoid valve,
  electric pump cut out inertia switch,
  ignition power module,
  ignition coils;
• devices connected to the cotnrol unit:
  radiator fan relays,
  climate control compressor relay (if fitted),
  Fiat CODE control unit.

Layout of system earth points

In order to increase the electro-magnetic compatibility and the operational reliability special care has been taken over the layout of the earth points, as shown in the diagram below:

1. control unit casing, connected to the vehicle bodyshell;
2. secondary coils connected under the cylinder head cover;
3. control unit internal earths (pins 6, 12, 107, 108, 116, 40, 48), Lambda sensor heater earth, relay earths, ignition power module earth connected to the engine cylinder block/crankcase.