Seven steps to clean fuel

High pressure in fuel systems improves fuel atomization and helps reduce emissions, but it can also cause accelerated abrasive wear in the fuel system. Our experts explain three major factors that affect fuel system life and offer seven recommendations to help you ensure that your fuel supply is as clean as possible.


Generally, there are three major factors that affect fuel system life:

  • WATER. Water breaks down the protective film strength of fuel, leading to plunger scuffing and seizure failures. Low sulfur fuels have lower film strength and lower natural resistance to scuffing or seizure.
  • ABRASIVES. Small abrasive particles enter the fuel tank through unfiltered tank vents or come from the petroleum distillation process. These particles cause the injector cartridge to wear out, which results in internal leakage and reduced fuel delivery.
  • SUPPLY PRESSURE. A pressure of about 100 psi achieves complete filling and proper operation of injectors. Low supply pressure causes incomplete filling, which results in erratic fuel delivery and eventually cavitation damage to the injector.


These seven recommendations will help you ensure that your fuel supply is as clean as possible:

  • FUEL TANK DRAIN. Condensation from regular heating and cooling cycles creates water in fuel storage tanks. Debris enters vented fuel caps through normal tank breathing. Both water and debris are heavier than fuel and settle to the bottom. Fuel tank drains should be located at the lowest part of the fuel tank and drained daily.
  • TWO-MICRON TANK BREATHER FILTER. Up to two-thirds of the dust trapped in the two-micron secondary fuel filter comes through the vented fuel cap. A two-micron tank breather filter can significantly extend secondary fuel filter life.
  • WATER SEPARATOR. While modern fuel injectors are designed to tolerate small amounts of water in fuel, poor fuel storage practices and condensation can cause undissolved water to accumulate. A water separator reduces water content so fuel film strength is not weakened.
  • PRIMARY FUEL FILTER. A 10-micron primary filter removes large abrasive particles and prevents premature clogging of the secondary filter. A combination primary fuel water separator filter and secondary fuel filter helps keep water out of the system.
  • BYPASS FLOW. Circulating fuel not used by the injectors is called bypass flow. An insufficient amount of bypass flow results in high fuel temperatures. “Cooking” of the fuel yields tar-like particles that can cause the nozzle check to stick open, resulting in overfueling. Regular fuel filter replacement helps to prevent this problem.
  • FUEL SUPPLY PRESSURE. If fuel supply pressure gets too low, a vacuum bubble can form. This may cause injector damage when system pressure recovers and the bubble implodes, causing cavitation wear. A “headless plunger” design, used in most new injectors, eliminates cavitation problems.
  • SECONDARY FUEL FILTER. As pressures up to 30,000 psi occur in injectors, even small particles cause excessive abrasive wear. A high-quality two-micron fuel filter helps reduce wear.