Fuel injection device for 4A-FE and 3S-FE engines [Toyota Carina T170]

The fuel injection device consists of three main groups: the fuel section, the air supply section and the electronic control elements. The fuel injection devices on both engines are different. An electric fuel pump supplies fuel under pressure to the injection valves (injectors). The injectors inject a precisely dosed amount of fuel into the intake manifold based on signals from the electronic control unit. Fuel is injected from all injectors simultaneously. At low engine speeds, injection is performed once per revolution, at high engine speeds, (over 6000 rpm) — every one revolution. The air supply system ensures sufficient air supply under all conditions. The electronic control system with the help of a microprocessor controls the following functions:

• 1. Electronic fuel injection. The control unit receives signals from various sensors that transmit data on the operating mode, including pressure in the intake manifold, intake air temperature, coolant temperature, engine speed and engine acceleration or braking. This data is evaluated in the microprocessor to determine the exact injection moment for the formation of an optimal air-fuel mixture.
• 2. Electronic ignition timing control. The electronic control unit is programmed with data for the optimum ignition timing. With the help of the various sensors mentioned above, the spark is generated by the spark plugs at the right moment.
• 3. Diagnostic function. The control unit registers each failure or malfunction in the system and lights a warning lamp on the dashboard. At the same time, the microprocessor remembers the failure. Thanks to this, the failure is immediately determined at the service station.
• 4. Failure monitoring. In the event of a microprocessor failure, individual functions are performed by a backup circuit, allowing the vehicle to be driven to the nearest service station. In this case, a warning lamp on the instrument panel lights up.

Figure 138 shows a diagram of the injection system on a 2.0L engine, indicating the position and connections of individual components. The figure shows a system operating with a catalytic converter as it is installed on most vehicles. Similar components are used on a 1.6L engine operating with a catalytic converter.





The text is quoted from the source website: www.ToyotaMAN.ru