Dodge Colt/Challenger/Conquest/Vista 1971-1989 Repair Guide

Electronically Controlled Fuel Injection (ECI) System



The ECI system consists of an electric control unit (ECU), two fuel injectors, an air flow sensor and other components.

The amount of fuel metered by the two injectors is determined by an electrical signal supplied by the ECU. The ECU monitors various engine and vehicle parameters, needed to calculate fuel delivery time (the frequency and duration of injection) of the injectors.

The fuel delivery time is modified by the ECU according to such operating conditions as cranking, cold starting, altitude, acceleration, deceleration and so on. The fuel is drawn from the fuel tank and forced by the electric fuel pump to the pressure line through a fuel filter. At the end of the fuel line, a fuel pressure regulator controls the fuel pressure at a preset value. Excess fuel is returned to the fuel tank by a return line.

The fuel injectors are installed in a mixer assembly and inject fuel upstream of the throttle valve. When a solenoid coil on the injector is energized, a needle valve opens injecting fuel, for the length of time determined by the ECU to match the operating conditions at hand. Each injector features a swirl nozzle that atomizes the fuel at a higher combustion efficiency.