The Four Basic Components of Electronic Fuel Injection System

The Four Basic Components of Electronic Fuel Injection System

The four basic components of the electronic fuel injection system are the ECU, Injectors, and Throttle sensor. These are important parts of your vehicle’s EFI system. If you’re wondering how your car works, keep reading. You’ll learn how the various parts work together to produce your desired power and emissions. After reading this article, you’ll be well-equipped to repair any problems you might have.


A vehicle’s electronic fuel injection system has many different parts. Its sensors provide a variety of information about fuel injection conditions. This data can either be analytic or digital. Throttle position sensors and mass airflow sensors produce analog data. A computer then uses this information to alter the fuel and air mixture. In some vehicles, a fuel injection system may even adjust the throttle to increase or decrease power output. Sensors of electronic fuel injection system should be carefully inspected and replaced if necessary.

The sensors in the EFI system are a network of components that measure various parameters, including air mass entering and exiting the engine. Several other sensors, including air temperature, open angle sensors, and oxygen sensors, also contribute to the accuracy of the composition of the gasoline coming from the injector. All of these sensors send information to the ECU, which processes the data. Several of these components can be customized for specific models and operating conditions.


The ECU is one of three major components in the electronic fuel injection system. This device processes data and sends it to the injector, which opens or closes based on the length and magnitude of the voltage. Much like a computer processor, the ECU processes data by generating varying voltages. The values of each voltage have specific meanings. While conventional fuel systems don’t use batteries, the ECU does. It also needs a constant current to operate.

An engine’s fuel needs are determined by several factors, including displacement, rpm, load, and inherent engine efficiency. In order to calculate these factors, an ECU needs inputs that will represent these variables. Some of these inputs are listed below. Depending on the type of engine, the ECU may use more or fewer of these sensors. If the engine isn’t equipped with an ECU, it may rely on the vehicle’s other electrical components, such as a throttle pedal, which controls the amount of fuel the engine receives.


The Fuel Injection System (EFI) uses a three-dimensional map to guide the injection of gasoline into the engine. The program calls for a richer fuel mixture when the engine is under a heavy load and a leaner mixture when the engine is under a light load. The timing of these injectors depends on a variety of factors including vehicle speed and fuel octane.

A microchip is used to calculate the amount of fuel to deliver. Most electronic fuel injection systems use direct wiring from the power train to the injectors. The ECU is then able to ground a circuit that supplies voltage to the injectors. The injectors themselves are spring-loaded solenoid pintle valves, and when energized by the computer, a solenoid pulls the valve open. Fuel then sprays into the engine, and when the circuit is cut, the fuel stops flowing.

Throttle sensor

The microprocessor 40 of the ECU 16 controls many different functions of the engine through software instructions. The microprocessor applies a fuel grid map, matrix, and look-up table to determine when to open and close the throttle valve, and when to open and close the fuel injector 42. The throttle valve is then opened, allowing pressurized fuel to flow into the air passage 20 of the throttle body 18. The resulting mixture then flows into the piston cylinder 28 of the engine 12.

Typically, the throttle position sensor has a low resistance value of approximately 5.6 kO. This means that a faulty throttle sensor can create a dangerous situation. Therefore, it’s important to ensure that the sensor is working properly to avoid a costly repair. The TPS sensor has three wires, including a ground wire. The resistance value of this sensor varies depending on whether the car is in the idle position or is in deceleration.