Protection against excess rpm

Protection against excess rpm

When engine rpm exceeds an upper threshold of 6900 rpm imposed by the manufacturer, engine operating conditions are critical.

When the ECU recognises that this threshold rpm level has been exceeded, it reduces injector control time.

When rpm drops to non-critical levels, control is restored.

Electric fuel pump drive

The fuel pump is governed by the ECU through a dual relay.
The pump stops when:

• engine rpm drops below 50 rpm;
• starting does not occur with key in «Marcia» position (timed enablement).
• if the inertia switch is activated.

Injector control

Injectors are controlled in sequential, phased manner. During start-up, however, all injectors are initially all controlled in parallel (full-group).

Injector control timing varies according to engine speed and intake air pressure in order to improve cylinder filling because this makes for better fuel economy, good handling and lower emission levels.

FIAT CODE IGNITION LOCK FUNCTION MANAGEMENT

The system features an anti-theft function. This is implemented through a special FIAT CODE control unit able to dialogue with the engine control unit, and an electronic key with a specific sender unit designed for sending an identification code.

Once the key has been turned to STOP, the FIAT CODE system de-activates the engine control unit completely.

When the key is turned to MAR, the following operations take place in sequence:

1. the engine control unit (whose memory contains a secret code) sends the FIAT CODE a request demanding that a secret code be sent to de-activate the function lock:
2. the FIAT CODE control unit responds by sending the secret code only after receiving a recognition code sent by the ignition key;
3. recognition of the secret code allows the engine control unit lock to be de-activated and normal operation to proceed.

NOTE When the FIAT CODE anti-theft system is present, it is extremely inadvisable to test the vehicle using another engine control unit. In this case, the FIAT CODE control unit would transfer the recognition code (unknown) to the test control unit, which would thus be rendered completely unserviceable on other vehicles.