Asynchronous Injection; During Acceleration Injection; Base Air/Fuel Ratio Compensation; Fuel Cut - Suzuki F6A Service Manual

Base Air/fuel ratio compensation

This Base Air/fuel ratio compensation is a long–term compensation. While the air fuel ratio feedback compensation
is a short–term one. As the engine is subject to change, deviation (as shown by 1 and 2 below) occurs in the air/fuel
ratio feedback compensation factor which is used to compensate the air/fuel ratio to its optimum value. However, the
range of the air/fuel ratio feedback compensation is limited and compensation beyond this limit is impossible. For
this reason, the ECM learns (or sets) the air/fuel ratio feedback compensation factor value so that its central value
becomes its optimum value (or sets the air/fuel learning compensation ratio as shown by (~) and (~) below) and also
uses it to adjust the fuel injection time. This compensation value is stored in the nonvolatile memory. In this way, it is
not erased even when the ignition switch is turned OFF and reflected in the next driving. It remains effective for
compensation of the injection time even when the feedback control is stopped. (The Base air/fuel ratio compensa-
tion factor is reset to "0" when the battery is disconnected.)

Fuel cut

There are two types: During deceleration fuel cut and high speed fuel cut
(1) During deceleration fuel cut
When the engine speed is high and the throttle valve is completely closed (when decelerating) the fuel injection
is stopped to prevent the catalyst from getting overheated.
Conditions for execution of during deceleration fuel cut:
The idle switch is ON, and
the engine speed exceeds the specified value (which varies depending on the cooling water temperature)
Conditions for recovery
the idle switch is OFF, or
the engine speed is below the specified value (which varies depending on the cooling water temperature).
(2) High speed fuel cut
To prevent the engine from over–running, the fuel is cut when the engine speed exceeds a certain level and
again supplied when it drops below that level.

Asynchronous injection

(1) During acceleration injection

When following conditions are met, an injection occurs immediately and asynchronously with the crank angle signal

When the idle switch is turned OFF.
Conditions for execution: Other than when the engine is started, and the idle switch is turned OFF.

When the throttle opening variation is large
The fuel is injected by such injection time that is in accordance with the throttle opening variation, the amount of the
basic injection and the cooling water temperature.
Condition for execution: Other than when the engine is started, fuel cut is not applied, and the idle switch is OFF.
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