What are fuel injectors and what faults can they cause? [2022]

11 Min Read
What are fuel injectors

Diesel engines rely on injection nozzles, also known as injectors, to guarantee that the correct quantity of fuel will always be delivered to the combustion chamber.

The engine’s smooth operation depends on these relatively small but highly stressed components, which are subjected to thousands of stress cycles per minute.

What are fuel injectors

Even though they are made of the best materials, these components nonetheless deteriorate over time.

Learn how to identify broken injection nozzles and fix them by reading the information in this text.

Pressure is required for direct injectors

Diesel engines are a type of internal combustion engine known as a “self-ignition” engine.

For the fuel to be burned, this indicates that they do not require a spark ignition in the form of a spark plug.

The upward movement of the piston generates a sufficient amount of compression pressure. This pressure is enough to cause the desired diesel-air mixture’s explosion.

However, it is essential to inject the correct quantity of diesel fuel into the combustion chamber at the precise moment it should be done to achieve the best possible results.

The diesel will not burn entirely if the droplets are too large. If they are too small, it will cause the engine to overheat and not function properly.

Injection nozzles, typically built as a pump-nozzle unit, are responsible for introducing the fuel into the combustion chamber at high pressure. This guarantees the reliable production of the intended scenario.

The accepted standard is between 300 and 400 bar. Nevertheless, Volvo offers a model that can function at a pressure of 1400 bar.

Direct injection can also be used in gasoline and diesel engines, which means that the two types of machines are not mutually exclusive. In addition to that, they use injectors.

Design and placement of the injectors

The injector consists of a pump and a nozzle, as indicated by the bracketed text. The combustion chamber can be seen through the protrusion of the nozzle. It is made up of a hollow pin with a hole of 0.2 millimeters in width.

The pump that injects the fuel into the combustion chamber at the required pressure is installed at the back of the same component.

Because of this, every injector has its very own pump. Its primary component is a hydraulic piston that is returned to its original position using a spring.

In gasoline-powered cars, the injectors in diesel engines are located where the spark plugs are in the upper part of the cylinder head.

What are fuel injectors

Defects on the injector

The injector is a mechanical component that is regularly put through a significant amount of strain. It is affected by and also contains mighty forces.

In addition, it is put through a significant amount of thermal stress. Coking in the nozzle or internally to the nozzle is the primary reason for defects.

Coking is the residue that is left over after fuel is burned incompletely. This results in plaque formation, which in turn makes the burn more severe and causes the plaque to grow in size.

Injector defects can cause the following symptoms:

– Bad engine start

– A high amount of fuel used per mile traveled

– Exhaust smoke that is black during load operations

– Engine jerks

A faulty injector is not only financially burdensome but also inconvenient.

It can potentially cause significant damage to the engine if it is not fixed as soon as possible. As a result, any issues that arise with the injectors should not be ignored but treated immediately.

Injector Diagnostics

Checking the functionality of the injectors in the engine can be done in a way that is not only straightforward but also wholly risk-free.

Rubber hoses and the same number of large cups as the number of cylinders in the engine are all required.

Each hose has a cup at its conclusion, which allows them to be connected to the return outlets of the injectors.

Start the engine, and then wait between one and three minutes before turning it off. If the injectors have not been damaged, each cup will have the same amount of fuel accumulated.

Injectors that are not working properly are distinguished by delivering either a significantly increased or decreased quantity of fuel through the system’s return outlet.

A test kit that can provide this diagnosis can be purchased for nearly one hundred dollars. Because it was developed specifically for this function, this comes highly recommended.

How to fix the fault

Before you start: The cost of injectors can be pretty high. You should plan on spending between 250 and 380 dollars on a single injector if you want to replace it.

As a result of the fact that injectors must always be replaced as an entire assembly, you should budget anywhere from 1,000 to 1,800$ for the replacement parts.

On the other hand, the good news is that there are currently a significant number of specialized businesses that can refurbish injectors.

During the process, the injection nozzle is given a thorough cleaning to remove any adhesions, and all worn parts, such as gaskets and clips, are replaced.

After testing, the injector is delivered to the consumer in essentially unused condition.

Additionally, there is a significant benefit to making use of reconditioned components: When remanufactured injectors are installed, it is not necessary to re-program the engine control unit because this step is unnecessary.

To accomplish this goal, each injector must be reinstalled in the precise location in which it was initially installed.

Taking apart the injectors should not be too difficult if you understand how they are constructed.

They are not installed with screws like spark plugs but instead are “just” snapped in place most of the time.

They are secured in their positions by the fasteners attached to the ceiling above them.

Nevertheless, it looks very different when put into practice. A significant amount of disassembly is required before one can access the injectors.

Suppose they are visible and the clips that hold them in place are not secure. In that case, the inexperienced repairer is frequently in for an unpleasant surprise: Even with the most significant amount of effort, the injector cannot be dislodged from its position in the engine because it is very securely fastened there.

To accomplish this goal, respectable manufacturers have developed special solvents that cause the caking responsible for the injector’s rigidity.

Nevertheless, even when a solvent is used, extracting an injector can be cumbersome and time-consuming.

The essential things to remember in this situation are to maintain a level of patience and to avoid doing any additional harm to the vehicle’s engine.

Make sure to check every injector

Because all injectors are put under stress almost simultaneously, the wear on them is also consistent.

Even if only one or two faulty injectors are found during the test, it is only a matter of time before all of the injectors fail.

Therefore, having the service company check all of the injectors is the most cost-effective course of action that can be taken.

You won’t be able to buy a new replacement component for an injector until the specialist certifies that the part can no longer be restored to its original condition.

You can save a significant amount of money and receive an engine that functions flawlessly.

Work that is both useful and complementary

The engine is essentially turned off when the injectors are taken out of the car.

As a result, this presents an excellent opportunity to carry out additional maintenance and repairs.

Regarding diesel engines, it is recommended that the EGR valve and intake manifold be cleaned as well. In addition, these deteriorate over time.

Additionally, the exhaust particulate filter could be taken out and cleaned by a trained professional.

When the refurbished injectors are installed, it is also possible to replace any current paper filters in the vehicle.

These filters include the pollen filter, the cabin air filter, and the engine air filter. Altering the diesel filter is another step to guarantee that the reconditioned injectors are supplied with clean fuel.

Finally, the last thing that needs to be done is to change the oil to keep the engine running smoothly and cleanly for the next thirty thousand miles so that you can begin the next thirty thousand miles worry-free.

Share this Article
Leave a comment