Fuel Delivery and Air Induction: Description and Operation

Fuel System:

- The Electronic Fuel Injection (EFI) system is a multi-point, pulse fuel injection system. This system supplies the engine with the fuel mixture necessary for efficient combustion. An air induction and fuel injection system work in conjunction with an electronic engine control system that consists of various sensors, switches, and an Electronic Control Assembly (ECA). The ECA which interprets the data it receives from sensors and switches. Computing when and for how long the injectors are energized.

- Requirement of fuel is determined from data supplied to the ECA by the Vane Air Flow Meter that measures the amount of air being drawn into the engine. Other sensors and switches are used to measure air temperature, atmospheric pressure, coolant temperature, engine speed, and exhaust oxygen content. Various sensors and switches detect changes in the operating conditions and send signals to the ECA. Permitting proper control over the opening duration of the injectors to maintain optimum exhaust emission control and engine performance

- The amount of fuel supplied to the engine depends on the duration of time that the injectors stay open. Between idle and 4,500 rpm, fuel is supplied by simultaneously providing one injection per crankshaft rotation (two injections per cycle) to all cylinders. Therefore one injection period supplies half of the fuel necessary for ideal combustion. Between 4,500 and 6,000 rpm, the injectors could remain fully open due to injector lag, resulting in poor performance and fuel control. For this reason, when the engine speed exceeds 4,500 rpm, there is a change over to one injection per two crankshaft rotations (one injection per cycle). When the engine speed reaches 6,400 rpm or higher, fuel injection is shut off in order to prevent the engine from overspeeding.

- During high speed operation, when the vehicle speed reaches approximately 113 mph and/or the engine speed reaches 6,300 rpm, fuel is cut so that vehicle speed does not exceed the speed rating of the tires.

- The fuel delivery system supplies filtered, pressurized fuel to each injector. The system consists of a high pressure electrical fuel pump mounted in-tank, fuel filter, fuel pressure regulator, fuel injectors, fuel pump switch (located in the Vane Air Flow Meter), fuel pump relay, fuel tank, inertia switch and connecting lines.