Electronic Fuel Injection: Description

This Electronic Fuel Injection (EFI) system consists of 4 sub-systems: Fuel delivery, air induction, engine sensors, and the Electronic Control Unit (ECU). The fuel delivery system includes a chassis mounted electric fuel pump, an in-tank boost pump, frame mounted fuel filter, fuel rail, injectors, fuel pressure regulator and fuel supply and return lines.

The air induction system consists of throttle body, fast idle valve, idle air compensator and intake manifold. Engine sensors include, the Manifold Absolute Pressure (MAP) sensor, Throttle Position Switch (TPS), speed sensor, and the coolant and air temperature sensors.

This combination of sub-systems, working together, creates a 2-group timed port injection system. The 2 groups are based upon engine firing order. The first group consists of cylinders 1, 2, 7 and 8; the second group is made up of the center 4 cylinders 3, 4, 5 and 6. All 4 injectors in either group are actuated at the same time and the separate groups are actuated alternately.

Seville models include a solenoid operated idle air compensator to control idle speed when the A/C compressor is operating. Sevilles sold in California use a closed loop fuel injection system. This system uses an oxygen sensor, located in the right side exhaust manifold, to sense oxygen content in exhaust gases. Differently calibrated ECUs are used for each model and cannot be interchanged.