Fiat 1995 Brava, Service Manual

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Engine
Bravo-Brava
iSt^v
Fuel system
10.
Starting
With the ignition key in MAR position, the E C U activates the electric pump for a few moments and ob-
tains data from the various sensors.
According to information from coolant temperature sensor, the E C U commands throttle valve opening
via direct current motor.The control unit recognises the start-up phase when the rpm value reading
from sensor (3) exceeds 30/min.
At very low temperatures, base pulse constants increase: the injector stays open longer and a richer mix-
ture is formed.
At very high temperatures, pulse constants are reduced to move closer to a stoichiometric ratio.
The control unit also contains an anti-flood function controlled by an internal timer that gradually re-
duces mixture enrichment when the engine fails to start for some reason.
During the stage following start-up, base pulse constants (ti) selected by the control unitareenriched
by a function that varies according to coolant temperature and is cancelled with time.
This constant does not remain the same throughout the activation period but is reduced gradually (by a
timer in the control unit)
During engine warm-up a further untimed coolant temperature-dependent enrichment takes place in
addition to the enrichment that occurs after starting:
This enrichment falls gradually in inverse proportion to engine temperature.
P4A04AJ01
4 Publication no. 506.670