Fuel Delivery and Air Induction: Description and Operation

Fuel System:

TURBO MODELS
The Electronic Fuel Injection (EFI) system is a multi-point, pulse fuel injection system. This system utilizes exhaust gas energy to pressurize intake air. It then supplies more than the normal amount of air into the combustion chamber. Resulting in a more fully charged combustion chamber a higher output and higher torque can be obtained by a turbocharged engine than by a non-turbocharged engine. The turbocharged air induction system and fuel injection system work in conjunction with an electronic engine control system which consists of various sensors, switches and an electronic control assembly (ECA). All sensors and switches are connected to the ECA which interprets the data it receives and computes when and for how long the electrically operated injectors are energized.

The basic requirement of the engine is determined from the data supplied to the ECA by the Vane Air Flow Meter which measures the amount of air being drawn into the turbocharging system. Other sensors and switches are used to measure air temperature, atmospheric pressure, turbine boost, coolant temperature, engine speed, and exhaust oxygen content. The various sensors and switches detect any changes in the operating conditions and send signals to the ECA. This permits proper control over the opening duration of the injectors to maintain optimum exhaust emission control and engine performance

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, pulsation damper, fuel injectors, fuel pump switch (located in the Vane Air Flow Meter), fuel pump relay, fuel tank, inertia switch and connecting lines.

When the engine is in the cranking mode, fuel is supplied to all cylinders simultaneously by providing one injection per crankshaft rotation (two injections per cycle). Therefore one injection period supplies half of the fuel necessary for ideal combustion.

Between idle and 6,000 rpm fuel is supplied through a two-group injection by providing one injection per two crankshaft rotations (one injection per cycle). At the completion of the first crankshaft rotation, fuel is supplied to cylinders #1 and #3 by determination of the cylinder identification sensor's signal created by the distributor. After completion of the second crankshaft rotation, fuel is supplied to cylinders #2 and #4.

To prevent engine overspeeding and possible damage, the fuel supply is cut if the engine speed continues at over 6,000 rpm for approximately 5 seconds. If engine speed momentarily exceeds 6,300 rpm, fuel is cut until engine speed drops to below 5,800 rpm. To prevent turbo overboost, the fuel supply is cut off when the intake manifold pressure exceeds the ECA specified values.

Fuel System:

NON-TURBO MODELS
The Electronic Fuel Injection (EFI) system is a multi-point, pulse fuel injection system. This system supplies the engine with the air/fuel mixture necessary for efficient combustion. An air induction system and fuel injection system work in conjunction with an electronic engine control system which consists of various sensors, switches, and an electronic engine control assembly (ECA). All sensors and switches are connected to the ECA which interprets the data it receives and computes when and for how long the injectors are energized.

The basic requirement of the engine is determined from the data supplied to the ECA by the Vane Air Flow Meter which 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. The various sensors and switches detect any changes in the operating conditions and send signals to the ECA. This permits proper control over the opening duration of the injectors to maintain optimum exhaust emission control and engine performance

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.

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.