Fiat 1998 Marea Weekend, Service Manual

Page: 280 / 846

Engine
Fuel system
Marea- Marea Weekend ft
99 update
10.
Rotation speed limiter
This strategy limits the maximum speed which
can be reached by the engine, gradually ena-
bling the cut-off, as illustrated in the table.
Maximum speed: 7150 rpm
^ ^ \ ^ C y l i n d e r s
mode ^ ^ ^ ^
1 2 3 4
1 cylinder
0
2 cylinders 0 0
3 cylinders
0 0 0
4 cylinders
0 0 0 o
Fuel pump operation
The fuel pump is operated by the engine management control unit via a relay.
The, pump cuts out:
- if the engine speed goes below 50 rpm;
- after a certain length of time (about 5 seconds) if the ignition is switched ON and the engine is not
started up (timed go ahead);
- if the inertia switch has been operated.
Operation of the injectors
The operation of the injectors is the phased, sequential type. However, during starting the injectors are op-
erated once initially in parallel.
The phasing of the injector operation varies according to the engine speed.
MANAGEMENT OF THE FIAT CODE ANTI-THEFT FUNCTION
The system is equipped with an anti-theft function. This function is achieved thanks to the presence of a
specific (FIAT CODE) control unit capable of dialogue with the engine management control unit and an
electronic key with a special transmitter for sending a recognition code.
Each time the key is switched OFF, the FIAT CODE system completely deactivates the engine manage-
ment control unit.
When the key is turned to the ON position, the following operations take place, in order:
1. the engine management control unit (whose memory contains a secret code) sends the FIAT CODE
control unit a request to send the secret code for deactivating the immobilizer function;
2. the FIAT CODE control unit responds by only sending the secret code after having, in turn, received the
recognition code transmitted by the ignition key;
3. the recognition of the secret code allows the deactivation of the immobilizer function for the engine
management control unit and normal operation can be resumed.
MOT E
The presence of the FIAT CODE anti-theft system means that it is not advisable to use another en-
gine management control unit during fault diagnosis. In such a case, the FIA T CODE control unit
would transfer the (unrecognized) code to the test control unit which could then no longer be
used on any other vehicle.
10
Print n° 506.763/15