To consummate the purpose of the fuel injection, fuel needs to be transported to it from the fuel tank. This process is the low-pressure fuel system components' role. The fuel system's low-pressure side comprises several parts like fuel tanks, fuel supply pumps, and fuel filters. Moreover, many fuel systems involve heaters or/and coolers to enhance the control for temperature.

Your diesel truck's fuel system functions to clean, deliver, supply, and transfer fuel to the engine's cylinders. This whole process will facilitate combustion, eventually inducing power. On the other hand, fuel systems may vary depending on the type of engine you have, but controlling the amount and supply of fuel to the combustion chamber is the fuel system's universal function.

Fuel System

The fuel system must measure the appropriate amount of fuel and transport the fuel to the injector assembly with exact timing simultaneously. Once the fuel is transported, the atomization and spray pattern of the fuel are the required conditions for the complete combustion to take place. Atomization is the result of pressure in the injectors and their holes. Now, the angle, spacing, and number of holes in the injector's tip establish the spray pattern

Current diesel engines have fuel systems that have exceedingly high pressures, reaching over 20,000 to 30,000 psi range. High pressure is necessary to guarantee enhanced fuel economy and exhaust emission that follows the strict regulation imposed by the Environmental Protection Agency.

The precision, supply, and timing of fuel delivery are crucial factors in the overall efficiency of the diesel engine operation. Relatively, the high pressure in the system is connected to stringent tolerances in the fuel system components, which affect the system's efficiency. These are the contaminants that came from refining, storage, mixing, and transporting diesel fuel. Contamination prevention is crucial since this will also aid the engine in avoiding significant issues from arising. Fuel system contamination is due to biological factors as well. The most common contaminants you can find in your diesel fuel are water, microorganisms such as algae, and inorganic elements. You might also experience oil in a coolant diesel engine. This means that there is a problem with some of your gaskets or reservoirs' seals.

Even if you have the best quality of fuel or where it is purchased, if you don't know how to take preventive measures, these contaminants will cause more issues to your engine than you can imagine. It is necessary to have proper diesel engine maintenance to guarantee efficiency and high economic fuel system life. It is also recommended to have a diesel engine maintenance checklist to follow.

The major components of the fuel system that you must include in your diesel engine maintenance checklist are the fuel tank, the fuel transfer pump, the injection pump assembly and injectors, and the fuel system filtration products.

Proper practices for your diesel engine maintenance include effective filtration, keeping fuel transfer equipment out of the rain, and using fuel pump filters. Moreover, adequate storage procedures to diminish temperature fluctuations prevent or reduce the effect of contamination.

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Fuel Tank and Fuel Supply Pump

The fuel tank is a stockpile that carries the fuel supply and aid in maintaining its temperature at a below flash point level. The fuel tank is also the key to dissipating heat from the fuel transported back to the engine. The fuel tank must be leak-proof and corrosion-resistant. It must also have safety valves to avoid too much accumulation of pressure.

Procedures in maintaining your fuel tank include visually examining the tank exterior, inspecting rust, and observing the interior for signs of algae growth or corrosion. If there are contaminants present in your fuel tank already, you must drain and clean it. If there are algae, you can use biocide to eradicate them. Biocides are readily available in the market. After that, the tank should be drained, and clean fuel must be refilled into it.

Fuel Filter

The fuel filter is the key to have a trouble-free operation in your diesel fuel system. Fuel filter aids in diminishing damage and over soon deterioration, which is caused by the retained fine particles of contaminants present in the system. The fuel filter prevents these contaminants and water from entering the fuel injection system.

Some fuel filters with a two-stage filter system usually use a primary filter for the inlet and a secondary filter on the outlet of the fuel transfer pump. The primary filter removes the larger particles while the secondary filter functions to endure high pressures and wipe out smaller particles which can cause severe damage to the engine's system. A one-stage fuel filter functions to remove larger and smaller particles in one go using a single filter.

Accurate Filtration

Proper filtration uses fuel or water separator and/or fuel filter and switching them at exact time intervals. It will clear away the contaminants before it enters to the fuel system's components.

Water may get into the fuel system due to natural condensation and causes leaks to storage tanks. It might be in large droplets form or emulsified. You must drain the engine so it can acquire optimum performance and longevity. Separators for fuel or water serve as mater removal and filtration. This will combine water removal and filtration and remove contaminants simultaneously. The fuel filter restriction index gives the operator a signal on the life of the fuel filter.


Your diesel engine oil must do its job by adequately lubricating the engine. You can use fuel additives to dissipate contaminants, improve fuel lubricity, lessen extreme temperature effects, and clean components. These will enhance filter and component life. Some products offer a gauge that can signal when to change the primary or suction fuel filter. The effectivity of fuel filters differs due to temperature, filter size, and fuel quality factors. The fuel filter restriction indicator gives the operator an easy-to-read gauge that offers feedback on the remaining life of the fuel filter.

One of the preferred and most popular diesel fuel systems is FASS Fuel System. It is designed to eradicate air and vapor locked in diesel fuel. It offers the cleanest possible burning fuel, delivers purified fuel, and increases lubricity in the overall engine system.

Read More: Fuel Injectors: Best Ways to Clean Them

To know more about the proper maintenance of your diesel truck's fuel system assembly and other diesel engine services, please contact us, or visit Pure Diesel Power for more info.