Negative Injection Correction – What Does It Mean and How Does It Manifest?

An integral part of any internal combustion engine is the fuel injection system, with injectors being its heart. They are responsible for delivering fuel to the combustion chamber and ensuring proper atomization. However, over time, irregularities in their operation can arise, leading to issues with engine performance. One such issue is negative injection correction, which I will discuss in more detail below.

What Is Injector Correction and Why Does It Occur?

As mentioned in the introduction, injectors are components that play a crucial role in the efficient operation of the engine. They control the amount of fuel that enters the combustion chamber – proper fuel dosing ensures smooth and trouble-free driving, while any irregularities can lead to issues like reduced engine performance or increased emissions. To maintain optimal engine conditions, the control unit continuously monitors various engine parameters (such as RPM, temperature, and pressure). Based on this data, it calculates and adjusts the appropriate fuel injection values – these adjustments are known as injection corrections. This optimization improves fuel efficiency, performance, economy, and emissions, assuming the corrections are within the correct range.

However, corrections can be "negative" or "positive" – both of which fall outside the norm and can negatively impact vehicle performance. Proper injector corrections are essential for the engine control unit to ensure smooth and optimal engine operation.

When Do We Talk About Negative Injection Correction and How Can You Identify It?

Negative (or reduced) injection correction refers to a situation where the amount of injected fuel is lower than the value set by the engine control unit (similarly, positive correction occurs when excess fuel is injected). In practice, this means that the engine is less efficient in burning fuel than it should be. How can you identify negative correction? The onboard computer may display an error code (P0171, P0172, P0174, or P0175). Additionally, certain symptoms can signal this issue, such as:

• Acceleration problems (evident through delayed response when pressing the accelerator pedal),
• Uneven engine operation, noticeable by vibrations and jerking during driving,
• Increased fuel consumption.

Causes of Negative Fuel Injection Correction

What could cause negative correction? It’s hard to pinpoint a single culprit, as several factors may be responsible, including:

• A clogged or blocked injector,
• A damaged or worn fuel pump,
• A blocked air filter,
• A restricted exhaust system,
• A damaged or worn-out oxygen sensor (lambda sensor).

How to Fix Negative Fuel Injection Correction?

Since there are many potential causes for this issue, the best solution is to visit a car service workshop for diagnostics using professional equipment. This will help identify the root cause, making it easier to take appropriate action. It may turn out that the problem can be resolved simply by cleaning the injectors, rather than full regeneration or replacement of parts.

At this point, I recommend a product available on the website tec2000.pl – TEC 2000 Diesel Injector Cleaner, a "liquid tool" designed to clean the tips and nozzles of injectors in diesel engines. The product is based on various cleaning and dissolving agents, as well as lubricants that extend the lifespan of diesel injectors.