Fuel Metering System

Fuel Injection Control System:

FUEL DELIVERY
The basic function of the fuel metering system is to control fuel delivery to the engine. Fuel is delivered to the engine by individual fuel injectors mounted in the intake manifold near each cylinder.

COMPUTER CONTROL
The main control sensor is the Heated Oxygen Sensor (HO2S), which is located in the exhaust manifold. The HO2S provides the ECM with exhaust stream oxygen content information. The ECM modifies the air/fuel mixture by changing the injector pulse width signal sent to the injectors. By constantly measuring the exhaust oxygen content and adjusting the injector pulse width, the air fuel ratio is kept very close to the optimal 14.7:1. This is the range at which the three-way catalytic converter operates most effectively and at which the vehicle's emissions are kept to a minimum. The constant tailoring of the air/fuel ratio based upon the HO2S feedback is referred to as "Closed Loop" operation.