Suzuki VLR1800, Service Manual

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1A-1 Engine General Information and Diagnosis:
Engine
Engine General Information and Diagnosis
General Description
Injection Timing Description
B822H11101001
Injection Time (Injection Volume)
The factors to determine the injection time include the basic fuel injection time, which is calculated on the basis of the
intake air pressure, engine speed and throttle opening angle, and various compensations. These compensations are
determined according to the signals from various sensors that detect the engine and driving conditions.
Compensation of Injection Time (Volume)
The following different signals are output from the respective sensors for compensation of the fuel injection time
(volume).
I718H1110268-03
Signal Descriptions
ENGINE COOLANT TEMPERATURE SENSOR
SIGNAL When engine coolant temperature is low, injection time (volume)
is increased.
INTAKE AIR TEMPERATURE SENSOR SIGNAL
When intake air temperature is low, injection time (volume) is
increased.
OXYGEN SENSOR SIGNAL
(For E-02, 19, 24, 33)
Air/fuel ratio is compensated to the theoretical ratio from density
of oxygen in exhaust gasses. The compensation occurs in such a
way that more fuel is supplied if detected air/fuel ratio is lean and
less fuel is supplied if it is rich.
BATTERY VOLTAGE SIGNAL
ECM operates on the battery voltage and at the same time, it
monitors the voltage signal for compensation of the fuel injection
time (volume). A longer injection time is needed to adjust injection
volume in the case of low voltage.
STARTING SIGNAL
When starting engine, additional fuel is injected during cranking
engine.
ACCELERATION SIGNAL/DECELERATION
SIGNAL
During acceleration, the fuel injection time (volume) is increased,
in accordance with the throttle opening speed and engine rpm.
During deceleration, the fuel injection time (volume) is decreased.