Causes of failure and repair of diesel engine nozzles

The failure of the diesel engine nozzles is fraught with high expenses for the purchase of new ones. However, Bosch specialists were able to find a less financially cost-effective solution to the problem - they taught service stations to repair injectors.

Causes of nozzle failure

The main cause of malfunctions in the injectors is poor quality fuel. Diesel with a high content of sulfur or water clogs the needle canal and nebulizer: the spray angle changes, the needle stops.

Less often wear washer and spring. If the adjusting gaskets can still be added to the spring, the washer must only be replaced. Very rarely the case deteriorates - it is damaged mechanically.

Symptoms of injector malfunction

The most paradoxical symptom is the sudden appearance of "speed" of the engine. This happens when the injectors supply more fuel than necessary. But this effect is soon replaced by the reverse - the car starts to smoke, fuel enters the lubricant line and the oil level rises.

After a long parking the car gets worse and smokes. Idling becomes uneven.

Repair of diesel engine nozzles

At the service stations, the nozzle is diagnosed, faults identified and, if possible, cleaned and replaced by worn out parts.

Before starting the diagnosis, the nozzle is cleaned from corrosion and dirt in an ultrasonic bath. Then, inspect the body for damage. For diagnostics, a plunger pump is used. With its help, the injection pressure and the mobility of the needle are measured.

Check for tightness is carried out with a maximum on the engine. The injector is connected to the pump connection through this device. The mechanic starter rotates the crankshaft. The injection of the diesel through the nozzle and the maximeter must begin at the same time - this is a sign of the normal starting pressure of the lifting of the needle.

Then the angle of spraying of the fuel at the stand is measured.

To independently check the efficiency of the injector, it is necessary to unscrew it and press it against the engine. Make a few turns of the starter. If the nozzle is OK, then it will start to spark, there will be a correct cone of burning fuel.

In garage conditions, repair of diesel engine injectors is almost impossible. The only thing that a motorist can do is clean the injector body with a brush. The main thing is to observe the ideal cleanliness when removing this part to avoid dust or grains of sand entering the threaded hole.

Do not use the car keys. They can not only erase the edges of the nut, but also crush it. For this procedure, they are suitable: they evenly distribute the load on the nut.

Equipment for repair of injectors and their diagnostics

The device for adjusting the injectors consists of:

• Fuel collector;
• Own injector;
• Fasteners for the tested injector;
• A tank;
• A manometer;
• The distributor;
• Plunger pump.

This device records the fuel pressure at the beginning of the injection and the rate of its fall. If the readings do not correspond to the norms, then on the same mechanism, adjustment is carried out - tighten or loosen the nozzle spring by an adjusting screw.

In the event that manipulations do not bring results, determine the worn out part and replace it.

Failure in injectors with electronic injection control is more difficult to repair: replacing the mechanical part is not difficult, and it is not always possible to find an electronic sensor. The destroyed atomizer can be replaced, but this procedure does not eliminate the problem completely: further work of the nozzle will be unpredictable. Specialists of SRT in such cases recommend to replace it.

Pump nozzle. Features of repair

Lowered pressure or wear of the nebulizer is determined during bench testing, as well as in the repair of Common Rail fuel injectors. The difference between pump injectors is that each of them is equipped with its own diesel feed pump.

The most common failure is the wear of the pressure valve, which is responsible for the metering of the fuel supply. After its replacement, a second adjustment is made at the stand. If it is not possible to adjust the pressure of the injector, then change the plunger (it is necessary to compress the fuel).

Criteria for assessing the quality of repair of diesel engine injectors:

1. When the fuel is injected into the injector, normal pressure is created.
2. The diesel does not flow out of the sprayer until the pump is closed.
3. The spraying torch has the correct shape.
4. After the end of the main injection, the pressure decreases smoothly.

After repairing the pump injectors of the diesel engine, make sure that its installation is at the right angle to the GB. Incorrect positioning can lead to failure of both the head of the unit and the device itself.

If the repair of the injectors of the diesel engine did not give results or was impossible, you have to change them. Select a new nozzle is better than the brand, which was installed by the manufacturer.