Beginner's Auto Maintenance & Repair

The Fuel System

Fuel System:

The Fuel System pumps fuel into the cylinders of the internal combustion engine. It mixes it with the perfect amount of air for combustion. There are two types: fuel injection and carburettors.

 

Illustration of a carburetor.
Illustration of a carburetor.

 

Before 1985 most vehicles used a carburettor.

A carburettor uses a venture (narrowed passage within the carburettor) to draw fuel from a float bowl based strictly on the volume of air flowing through the carburettor.

A carburettor is a primitive method of mixing air and fuel.

It is far less efficient than modern fuel injection.

That’s why all modern cars today are built with fuel injection.

How a Fuel Injection System Works:

How a Fuel Injection System Works: Fuel injection is a complex electrical circuit using multiple sensors as inputs to a PCM (powertrain control module, also called the computer). The PCM then interprets the inputs from these sensors and produces a PWM (pulse width modulated) signal.

A PWM signal is digital on/off signal. It will inform you how much fuel is injected into the engine. The PCM then receives feedback signals from oxygen sensors. An oxygen sensor is a sensor that checks the air-fuel ratio by monitoring exhaust gas at or near the exhaust manifolds. Using this information, the PCM can adjust fuel trim accordingly to keep the engine running clean, long and efficiently. Burning less fuel and cleaner emissions will lead to a long engine life.

 

llustration of a fuel injector.
llustration of a fuel injector.

Fuel Filter and Air Filter: They protect the fuel system and engine. The fuel system is susceptible to contamination and debris. A small amount of contamination can cause severe problems in any fuel system. Therefore, these filters are critical for protecting the fuel system and engine.

 

Fuel Filter and Air Filter:

They protect the fuel system and engine. The fuel system is susceptible to contamination and debris. A small amount of contamination can cause severe problems in any fuel system. Therefore, these filters are critical for protecting the fuel system and engine.

 

 

A fuel filter (white) next to the air filter compartment (circular black part)
A fuel filter (white) next to the air filter compartment (circular black part)

 

When you fill your vehicle with fuel from a gas station, the energy will have contaminants. Between the fuel tank and the engine, the fuel passes through a sock filter, preventing large contaminants. Then the fuel will pass through the filter, preventing small contaminants from passing.Anything that moves through the fuel filter will also pass through the fuel system. Look at your owner’s manual to find the manufacturer’s recommendation for the mileage in which the fuel filter should be changed.

An air filter protects the engine from dust and dirt entering the air intake system. Any land in the engine can cause engine wear and eventually lead to engine failure. Therefore, an air filter, like the fuel filter, is also critical to any internal combustion engine. The air filter is inspected with every oil change and changed as needed.

 

Various air filters.
Various air filters.

 

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