Diesel fuel injectors: diagnostics and repair

A large number of motorists are faced with breakdowns and poor-quality functioning of parts of the power system of diesel power plants. This leads to loss of power, traction characteristics, work with interruptions. The cause of all this can be faulty diesel fuel injectors or their constituent parts.

The process of passing the injection

The power supply of the engine originates from the tank, from where the fuel is taken by the high pressure pump. After that, it moves through the piping system separately into each nozzle and the combustion chambers of the cylinders.

When the required pressure is reached, the plunger needle overcomes the spring force and rises, resulting in an injection. It is important that the frequency of work is maintained - the plunger must open and close in time. In the case of non-closing, the stability of the motor will be impossible due to the absence of spraying.

Ignition occurs due to the compression temperature - the fuel must be supplied to the cylinder in the form of very small hygroscopic particles. The needle part is not equipped with a sealant, therefore, through some of the backlashes, the mixture can enter the chamber of the arrangement of a spring mechanism with a pusher.

For the removal of fuel, a return channel is provided so that the plunger is not locked. There are nuts on the part used to control the injection pressure. The body with the elements of the mechanism is covered by a clamping washer.

Constituent elements

Fuel injectors for diesel engines consist of a hull, systems for the passage of diesel fuel, a plunger pair (a needle, a pusher, a spring), a fuel supply and discharge chamber, and a saddle of a plunger needle.

The channels are designed to deliver power from the pump. The spring must operate at a certain pressure, so that the needle is lifted in time, the formation of the spraying flare is carried out, and the combustion chamber of the engine cylinders is supplied. There are also no sealing gaskets - everything is guaranteed by the precision of manufacturing parts.

What can prevent normal spraying

The formation of the nominal spraying process depends on the healthy state of the spring, the pusher and the presence of various workings of the parts preventing the closure of the system. Under the influence of certain lateral forces, the plunger needle is pressed against the body, preventing full closure.

To protect against such effects, the structure is provided with a pusher, absorbing lateral loads, caused by the curvature of the spring. But it may not perform its functions as a result of the appearance of metal workings. Then you need to replace the pusher or spring mechanism. The need to change the case arises extremely rarely.

How to dismantle diesel fuel injectors

All work is carried out with an inoperative power plant in accordance with safety regulations.

Initially, you should inspect the site for dirt and other excess particles.

After this, you need to do a thorough cleaning of the landing site, wipe it with rags and blow it with compressed air, using a conventional vacuum cleaner with a blowing function or a compressor. It will require a set of locating wrench to turn the main and return piping.

Removal and replacement of fuel atomizers is carried out by a head or a pipe wrench. Use (for twisting this part) carob tools is highly undesirable - there is a risk of deformation of the faces. And this can lead to difficulties during removal or force to change the part of the case.

After unscrewing the nozzle, well clean the installation well and all the screw connections. The presence of weeding particles in the thread will adversely affect the density and state of the entire joint.

After cleaning, we put washers and sealing rings of fuel injectors made of copper. The planting area must be treated with graphite lubricant. A good connection state will allow the part to be twisted almost to the end, without exerting any effort. The key should be moderately compressed and proceed to the connection of fuel pipelines.

What problems can be caused by the sprayers

A significant part of car enthusiasts often puzzles over the problem of a long engine start.

In this case, there is an effect of initial work, but in a short period of time unstable functioning is demonstrated. The reason may be the unsatisfactory condition or the incorrect operation of the nebulizers.

There are cases when an uneven amount of diesel fuel is supplied to the cylinders and this increases its consumption. Either the supply is too small for the motor to operate normally. It is possible and the possibility of poor-quality spraying.

If you do not respond in time to such symptoms, you may need to replace the injectors. The serviceability of the power components determines the stable operation of the power plant.

How to replace the spray gun

To implement the solution of the problem of setting up new elements, their acquisition will be required. And in the presence of elements, it is required to dismantle diesel fuel injectors, following the recommendations for the correct implementation of these operations.

Next, you need to disassemble the parts, replace the spray unit and assemble in the reverse order. It is necessary to exclude the possibility of getting inside the device and the place of mating of dirt and mechanical abrasive particles. This can lead to a rapid failure of new parts or to their unsatisfactory functioning. All elements must be washed in containers with clean gasoline.

Please note that during all operations, it is necessary to cover the openings and outlets of fuel pipelines with protective caps.

Setting the engine without checking the performance of parts will not bring the desired result. A stand for testing the injectors will help determine and adjust the required parameters.

What is the algorithm for setting the injection parameters

When dismantling operations are carried out, resulting in the replacement of individual components or components, it will be necessary to determine and regulate performance. At home, it is extremely difficult to do such a complex of operations without proper logistics.

The equipment for checking the battery of the motor is very expensive, so you will need to visit a specialized workshop where there is a test stand for injectors. The wizards will diagnose and configure the following indicators:

• Rated working pressure of injection;
• Adjustment of the spray flare: before the plunger needle operates at the set pressure values, any leaks or jets of fuel are not allowed;
• Checking the spray cone, which must have clear boundaries and act in the direction from the hole without any displacement in any direction;
• Correctness of the work process.

The adjustment is carried out under conditions similar to those in which the nozzles are mounted on the motor. Verification takes place with real workloads.

In the conditions of the SRT, it is possible to perform ultrasonic cleaning of the elements of the power system.

What methods to flush the fuel supply parts

Diesel fuel injectors often suffer partial or total clogging. The problem is the composition of the fuel. It contains a variety of resins. There are such ways of removing weeds:

1. Do not remove the elements from the engine, by adding to the refueling tank special chemical additives. During operation, the contamination will be dissolved and removed from the system.
2. Cleaning with ultrasonic devices. The parts are located inside the working chamber of the device, and under the influence of low-frequency waves, various deposits are removed. This procedure does not take a lot of time and money, but it gives a good result.
3. Self-cleaning in tanks with clean diesel or gasoline. It can be held at home or in the garage, this will not cause any difficulties.
4. Cleansing of resinous deposits with the help of special tools on the stands.

If the defects are not detected in time and the service performed, the injectors may need to be replaced.

What is the cost of parts of the power system

The purchase of devices that supply fuel to the combustion chamber of diesel power plants is not a cheap business.

Depending on the brand, model of the car and the manufacturer, the fuel diesel prices for the nozzles are kept within the limits of 10 to 25 thousand rubles, and in some cases even higher. A major overhaul of such parts at the service stations will cost from 5 to 9 thousand rubles per set.

Sizes of nozzle power supply systems for motors

By design and principle of operation, the following types of nozzles are distinguished:

• Mechanical. These elements are installed on early car models and tractors. They have an understandable structure and simple algorithm for assortment-assembly operations;
• Electromechanical. Are present on foreign cars of middle age;
• Piezoelectric. The latest development, which is present on the recently produced vehicles brand manufacturers. They differ in complex construction and high cost.

The material for making nozzles has many varieties. The main raw materials are brass, titanium alloys, silicon carbide, as well as special alloys of strong stainless steels.

The service life of such elements depends on operating modes and harmful influences and can amount to several tens of years of intensive work. It will only be necessary to replace the parts.