Fuel Injection - BOSCH AFC - JAPANESE Models: Description

The Bosch Air Flow Controlled (AFC) electronic fuel injection system uses sensors to detect engine conditions. System consists of airflow meter, various sensors and switches, air cleaner assembly, Electronic Control Unit (ECU), throttle chamber, air and pressure regulators, injectors and connecting wires and hoses. The ECU receives sensor signals to determine amount of fuel and length of time that fuel is to be injected into engine.

An airflow meter, mounted between the throttle chamber and air cleaner, measures amount of intake air. Fuel injector on time is based on amount of intake air required for one rotation of engine. System maintains a constant fuel pressure and accurately balances air/fuel mixture under all operating conditions.

An automatic altitude feature is used on all models. The intake air sensor transmits air flow information to the ECU while the distributor supplies engine RPM data. Toyota Supra models incorporate an oxygen sensor into the Bosch AFC fuel injection system. The system consists of an oxygen sensor mounted in the exhaust manifold, a modulating or frequency valve, a 3-way catalytic converter and a modified electronic control unit.