Fiat 1998 Marea Weekend, Service Manual

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Marea- Marea Weekend ft
99 update
16v
Engine
Fuel system
10.
Operation in acceleration conditions
During this stage, the control unit increases the quantity of fuel supplied.
The "basic" injection time is multiplied by a coefficient which depends on the temperature of the engine
and the opening speed of the accelerator butterfly (average vaule 1.2).
If the sharp variation in the injection time is calculated when the injector is already closed, the control unit
reopens the injector (extra pulse) to compensate the mixture strength as quickly as possible: the subse-
quent injection are, however, already increased according to the previously mentioned coefficients.
A: normal injection time
B: extra-pulse
C: injection time including enrichment
OFF: engine at stationary speed
ON: engine in transition
Operation in deceleration conditions
During this stage a negative transition strategy is implemented to decrease the quantity of fuel supplied:
the "basic" injection time is multiplied by a coefficient which depends on the temperature of the engine
and the engine speed and load conditions in the moment immediately preceding the start of the decelera-
tion.
Operation in cut-off conditions
The cut-off strategy is implemented when the control unit recognizes that the butterfly is in the idle posi-
tion (signal from the butterfly potentiometer) and the engine speed is above 1600 rpm (with the engine
warm).
The supply to the engine is re-enabled when the butterfly is recognized not to be in the closed position or
when the engine speed goes below 1200 rpm (with the engine warm).
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