How fuel system flushes improve engine reliability

A proactive and easy-to-use solution, like a comprehensive fuel system flush, is the only tool that allows fleet managers to take back control and ensure fuel system integrity, regardless of the quality of the diesel received. To achieve this necessary control over operational efficiency, Power Service has introduced Diesel Injector & DPF Flush, a new, comprehensive solution designed to be a core part of your preventive maintenance routine.

The chemistry of clogging: Why injectors fail

Injector issues boil down to two main types of deposits, both fueled by the inherent chemistry of diesel, its aging process, and contamination:

1. Internal diesel injector deposits (IDIDs)

These occur inside the injector body, typically on the critical moving parts like the control valve. They often are formed by contaminants such as trace amounts of minerals like sodium, calcium, zinc, or fatty acid methyl esters (FAME) that get past filtration. In the extreme heat and pressure of the HPCR system (often exceeding 30,000 psi), these trace elements polymerize and form deposits.

IDIDs physically impede the motion of internal components. They can cause injectors to stick open or closed. This leads to slow injection response times, rough idling, lost power, inconsistent fuel metering, and a loss of precise timing — all of which compromise the engine's ability to operate efficiently and can lead to premature wear and tear.

2. External injector tip deposits (nozzle coking)

These are visible deposits that build up on the nozzle and tip of the injector, where the fuel meets the combustion chamber. These are composed primarily of asphaltenes, paraffins, and un-combusted hydrocarbons. As the injector tip operates, residual unburned fuel on the hot surface "cokes" or hardens into varnish-like deposits.

Nozzle coking physically alters the shape of the fuel spray. Instead of a precisely atomized, fine cone, the spray pattern becomes distorted — leading to fuel droplets that are too large and unevenly distributed in the cylinder, causing incomplete combustion and excessive exhaust.

The cascading failure: From poor combustion to DPF overload

The primary function of the injector is to ensure complete combustion. When deposits distort the spray pattern, that primary function fails, initiating a costly domino effect that leads directly to DPF issues.

1st  incomplete combustion: When fuel droplets are too large due to a fouled nozzle, they cannot vaporize and mix with air effectively before the combustion event ends. This results in incomplete combustion and an immediate spike in the production of particulate matter or soot.

2nd DPF overloading: The DPF is designed to capture this soot. However, if the engine is producing 10%, 20%, or even 30% more soot than normal due to poor injection, the DPF reaches its capacity threshold much faster.

3rd regeneration frequency spike: This decrease in the miles between regenerations is where your costs can soar:

• Fuel consumption: Active regeneration involves injecting fuel post-combustion to raise the exhaust temperature to over 1100 degrees F to burn off the trapped soot. Increased frequency equals increased fuel consumption.
• Downtime: Frequent regeneration means the vehicle either is tied up sitting idle to complete the cycle or, worse, requires a manual, forced regeneration, leading to operational downtime.

4th fuel economy deterioration: Beyond the DPF-related costs, injector contamination and subsequent incomplete combustion directly sabotage fuel economy (MPG). Deposits, whether internal or external, compromise the efficiency and precise timing of the fuel delivery. When the fuel spray is distorted, a significant portion of the diesel fails to convert into useful kinetic energy, effectively wasting fuel. Furthermore, the Engine Control Module (ECM), detecting the compromised combustion quality, may attempt to compensate by advancing timing or increasing the quantity of fuel injected to meet performance demands, creating an immediate and continuous drop in the fleet's average fuel economy.