Fiat 1998 Marea Weekend, Service Manual

Page: 278 / 846

Engine
Marea- Marea Weekend
ft
Fuel system 99 update
10.
Starting and post-starting
During starting, the engine timing cannot be recognized therefore the phased injection cannot be imple-
mented.
Whilst the engine is first running, an initial simultaneous injection is carried out (also because the consid-
erable fluctuations in the rotation speed do not allow the injection timing to be calculated correctly) and
later on the injection becomes the phased type.
The "basic" injection time is increased by a multiplication coefficient for the entire time the engine is
driven by the starter motor.
Once the engine is started up, the coefficient is gradually reduced until it disappears after a certain length
of time, the lower the temperature of the engine, the longer this time.
K: enrichment coefficient
t: time
a: engine temperature function
decrease
ON: engine driven (crank)
OFF: engine started (run)
4F007OJ01
Operation when cold
Under these circumstances the mixture is naturally weakened as a result of the reduced evaporation and
strong condensation of the fuel on the inner walls of the intake manifold: in addition, the increased vis-
cosity of the lubricant oil causes an increase in the passive resistance of the engine.
The "basic" injection time is corrected by a multiplication coefficient which depends on the temperature
and speed of the engine.
Operation in full load conditions
The strategy is enabled when the butterfly opening exceeds 70°.
The "basic" injection time is multiplied by a coefficient (function of the engine speed) equal to about 1.1.
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Print n° 506.763/15