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Causes of breakdown and repair features of diesel engine injectors

Causes of breakdown and repair features of diesel engine injectors
Causes of breakdown and repair features of diesel engine injectors

The failure of diesel injectors is fraught with high costs for the purchase of new ones. However, Bosch specialists managed to find a less financially costly way to solve the problem - they taught car services how to repair nozzles.

Causes of injector failure

The main cause of injector failures is low-quality fuel. Diesel with a high content of sulfur or water clogs the channel of the needle and the atomizer: the spray angle changes, the needle stops.

diesel injector repair

The washer and spring wear out less often. If shims can still be added to the spring, then the washer must only be replaced. Very rarely the case becomes unusable - it is mechanically damaged.

Injector failure symptoms

The most paradoxical symptom is the sudden appearance of "agility" of the engine. This happens when the injectors deliver more fuel than they need. But this effect soon reverses - the car starts to smoke, fuel enters the lubrication lines and the oil level rises.

Afterlong-term parking, the car starts up worse and smokes. Idle becomes uneven.

Diesel injector repair

At service stations they diagnose the injector, identify malfunctions and, if possible, clean it and change worn parts.

Before starting the diagnostics, the nozzle is cleaned of corrosion and dirt in an ultrasonic bath. Then they inspect whether the body is damaged. For diagnostics, a plunger pump is used. It measures injection pressure and needle movement.

The leak test is carried out using a maximometer directly on the engine. The nozzle is connected to the pump fitting through this device. The mechanic turns the crankshaft with a starter. Diesel injection through the nozzle and the maximeter should start at the same time - this is a sign of normal pressure to start lifting the needle.

Then the fuel spray angle is measured on the stand.

To independently check the performance of the nozzle, you need to unscrew it and press the thread to the engine. Make a few revolutions with the starter. If the nozzle is working, it will start to spark, the correct cone of burning fuel will appear.

In garage conditions, repair of diesel engine injectors is almost impossible. The only thing a car enthusiast can do is to clean the nozzle body with a brush. The main thing is to be perfectly clean when removing this part to avoid getting dust or grains of sand into the threaded hole.

Don't use wrenches. They can not only erase the edges of the nut, but also crush it. Forthis procedure, caps are suitable: they evenly distribute the load on the nut.

Equipment for injector repair and diagnostics

Injector adjuster consists of:

  • fuel collector;
  • own injector;
  • mounts for test injector;
  • tank;
  • manometer;
  • distributor;
  • plunger pump.
injector repair equipment

This device records the fuel pressure at the beginning of injection and the speed of its fall. If the readings do not meet the standards, then the adjustment is carried out on the same mechanism - they clamp or loosen the nozzle spring with the adjusting screw.

In the event that manipulations do not bring results, the worn part is determined and replaced.

fuel injector repair

A malfunction in injectors with electronic injection control is more difficult to repair: it is not difficult to replace the mechanical part, and it is not always possible to find an electronic sensor. A destroyed atomizer can be replaced, but this procedure will not completely eliminate the problem: further operation of the nozzle will be unpredictable. Service station specialists in such cases recommend replacing it.

Injector pump. Repair Features

Reduced pressure or wear of the nozzle is determined during bench diagnostics, as well as when repairing common rail fuel injectors. The difference between pump injectors is that each of them is equipped with its own diesel supply pump.

pump nozzlediesel engine repair

The most common failure is the wear of the pressure valve responsible for metering the fuel supply. After its replacement, re-adjustment is carried out on the stand. If it is not possible to adjust the nozzle pressure, then change the plunger (needed to compress the fuel).

Criteria for assessing the quality of diesel injector repair:

  1. When fuel is supplied, normal pressure is created in the nozzle.
  2. Diesel does not flow out of the atomizer while the pump is closed.
  3. Spray pattern is correct.
  4. After the end of the main injection, the pressure decreases smoothly.

After repairing the diesel engine pump injector, it is necessary to ensure that its installation takes place at the correct angle to the GB. Incorrect positioning can lead to failure of both the head of the block and the device itself.

If the repair of diesel engine injectors has not yielded results or proved impossible, they have to be changed. Choose a new nozzle better than the brand that was installed by the manufacturer.

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