PETROL INJECTION
Fault finding - System operation
17B
17B - 11
PETROL INJECTION
Fault finding - System operation
17B
17B - 11V9 MR-372-J84-17B050$094.mif
S3000 Injection
Program No.: AD
Vdiag No.: 4C / 54
Adaptive idling speed correction:
Under normal warm operating conditions, the idling speed opening cycle ratio value PR091 Idling speed regulation
theoretical OCR varies between a high value and a low value to obtain the nominal idling speed.
After operating dispersion (running in, engine fouling, etc.), the opening cycle ratio value may be close to the high or
low values.
The adaptive correction PR090 Idling speed regulation programming value on the idling speed opening cycle
ratio compensates for the gradual variations in the engine's air requirement, by bringing the idling speed opening
cycle ratio back to an average nominal value.
This adjustment only takes effect if the coolant temperature is above 75 °C, 1 minute after starting the engine and
during the idle speed regulation phase.
Idling speed setpoint calculation:
The idling speed setpoint is given by parameter PR010 Idle speed regulation valve setpoint.
The idling speed regulation setpoint depends on the coolant temperature, the depollution programming, the climate
control requirements, the position of the gearbox selector, any power assisted steering action, the passenger
compartment heating resistors, the oil temperature (engine protection) and the electricity balance calculated by the
injection software (the engine speed is increased by 160 rpm maximum if the battery voltage remains below 12.7 V).
Richness management
For optimal operation of the catalytic converter, the richness must be maintained around 1.
Richness regulation is controlled by the upstream sensor. The sensor gives voltage according to the difference
between the partial oxygen pressures contained in the exhaust and a cavity filled with a reference mixture
(atmosphere).
As the partial oxygen pressure in the exhaust is representative of the richness, the voltage supplied to the computer
represents a Rich - Lean signal.
Adaptive richness correction:
In loop mode, the richness regulation corrects the injection duration in order to obtain a mixture which is as close as
possible to a richness of 1. The richness correction value PR138 Richness correction is close to 50 %, with limits
of 0 and 100 %.
The richness adaptive corrections PR143 Self-adapting richness gain and PR144 Self-adapting richness offset
are used to offset the injection mapping to centre richness regulation on 50 %.
Adaptive corrections take 50 % as an average value after computer initialisation (clearing the programming) and have
the following limit values:
