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The Different Parts of Diesel Engine Fuel Systems

The systems for diesel vehicles boast specific designs that differ significantly from regular gas vehicles, and one of the most important systems is the diesel fuel system. The system uses an intricate set of components to produce the right amount of pressurized and atomized fuel in the engine’s cylinders at the right time for optimal function. Below, we explain the different parts of diesel engine fuel systems.

Fuel Tanks

Fuel tanks are designed to carry the fuel that will be injected into the diesel engine. These tanks must be able to store enough fuel to keep the diesel engine completely operational for extended periods of time. This is especially crucial for semi-trucks used to transport shipments over long distances. The tanks must remain closed to keep any foreign particles from making their way through the fuel into the engine. The tanks have a few necessary openings; for instance, tanks have vents to let air in, which replaces the fuel as your vehicle uses it. There are three other openings: one to fill the tank, one for discharging the fuel, and one for returning unused fuel to the tank.

Fuel Lines

Diesel vehicles typically have three different types of fuel lines. High pressure fuel lines are built to handle the high pressures created between the fuel injection pump and the injectors themselves. On the same hand, mid-pressure fuel lines can tolerate light to medium fuel pressure, and they should sit between the fuel tank and injection pump. The third type is a low pressure fuel line that can be placed in areas that experience little to no pressure.

Diesel Fuel Pumps

High-speed diesel fuel systems require diesel fuel transfer pumps to supply fuel to the injection system automatically. There are also injection pumps designed to compress the fuel before it gets injected.


The diesel fuel filters are also extremely important for the fuel system. One of the main things the system and engine need protection from is any foreign particles. These can easily clog the fuel system, so diesel fuel must be filtered several times to prevent these issues. Some diesel systems will have three progressive filters. This includes a filter screen near the fuel transfer pump and tank. There should also be a primary fuel filter and then a secondary filter. These will remove any dirt that could act as a contaminant. However, some do not have a secondary filter.

Fuel Injectors

Of the different parts of diesel engine fuel systems, this is one of the most essential components. A diesel engine’s function is reliant on the even distribution of atomized, pressurized fuel throughout the cylinder. The diesel fuel injectors are designed to produce an electrical charge in some solid materials in response to mechanical stress. As such, they have quality precision and can handle the heaviest pressure. These fuel systems make it possible for diesel engines to offer better fuel economy than gas engines.

Canadian Diesel Online is proud to carry performance parts for various makes. For example, if you must replace any of your Ford diesel vehicle’s fuel system components, you can turn to Canadian Diesel Online’s part selection. We offer Ford diesel parts from Canada that you may need for your specific repairs—and more.