Fiat Bravo Service Manual page 154

Bravo-Brava
Starting and post-starting
During start-up, engine phase cannot be identified and phased injection cannot therefore be imple-
mented.
An initial simultaneous injection is carried out during the first few engine revolutions (full group) be-
cause the considerable fluctuations in rotation speed do not permit injection time to be calculated cor-
rectly. Only subsequently does injection becomes phased.
The base pulse constant is increased by a certain factor throughout the period when the engine is
cranked by the starter motor.
Once start-up has taken place, the factor is gradually reduced to zero within a given time period, which
is in inverse proportion to engine temperature.
Cold operation
Under these conditions, the mixture becomes naturally leaner due to reduced evaporation and heavy fu-
el condensation on the intake manifold internal walls. The greater viscosity of the lubrication oil also
brings about an increase in the rolling resistance of internal engine components which also serves to ex-
acerbate matters.
The electronic control unit recognises this condition and corrects injection time on the basis of the
coolant temperature signal.
Copyright Fiat Auto
@ i
16v
k: enrichment factor
t : time
a : decrease proportional to engine
temperature
ON: engine cranked
OFF: engine running
P4A05CJ01
Engine
Fuel system
10.
P4A05CJ02
5