Most common reasons
There are three main factors that can lead to unstable operation of the fuel injection system:
- Low quality fuel is a common problem in all post-Soviet countries.
- A long service life can equally be attributed to both advantages and disadvantages.
- Unprofessional repair work.
It should be noted that unqualified repairs are the most dangerous factor that can affect the normal operation of the injector. In the absence of certain theoretical and practical knowledge, it is not recommended to try to repair or clean the injector yourself. It is best to entrust such work to professionals who are well aware of all the nuances and features of carrying out work of this kind.
Improper cleaning of the injector can cause harm
There can be a great many reasons for a malfunctioning injector, so in this article we will analyze only the most typical signs of an injector malfunction inherent in engines of various types, and give recommendations for eliminating them.
Main symptoms
Lack of fuel mixture in the injector. Often, the presence of this symptom does not indicate a malfunction of the injector itself, but a failure of the fuel pump, or its incorrect installation after repair work.
In some cases, the reason may be a clogged fuel mixture inlet into the fuel pump. The fuel pump has failed.
Significant increase in fuel consumption. A fairly common phenomenon that indicates a clogged injector. Due to the small diameter of the injector nozzle, even slight contamination can significantly disrupt the mixture formation process, reducing the percentage of engine efficiency. This is explained by the fact that a clogged nozzle no longer forms a cone-shaped cloud of gasoline, which means that a significant amount of fuel begins to burn out in the exhaust manifold. The consequence of these processes is a deterioration in the dynamic characteristics of the vehicle and an increasing load on various electronic equipment of the car: coil, spark plugs, wiring, etc.
Idle speed sensor needs to be replaced
Unstable idle speed of the fuel injection system. This symptom can be the result of many malfunctions. The most likely cause is a malfunction of the idle air control valve or a clogged internal surface of the throttle pipe.
Problems starting the engine. If the vehicle engine does not start while the sounds of the fuel pump are heard, it becomes necessary to check whether the injector has a spark. For these purposes, experts advise using a spark gap.
It is not recommended to resort to checking the spark for a break, because Such actions can damage the ignition module and controller.
Trouble due to cylinder failure
Troit injector. In most cases, the culprit of this symptom is the presence of one or more inoperative cylinders. The breakdown can be eliminated by identifying non-working cylinders and then repairing them or replacing them with new parts.
Overflow of fuel mixture in the injector. This symptom also requires detailed diagnostics, which is best started by checking the sensor responsible for the throttle position.
Professional washing of the injector
The above signs of injector malfunction indicate the need for repair and maintenance work. You should not diagnose and clean the injector yourself if you are not 100% confident in your knowledge and experience. Specialized service stations are equipped with high-tech equipment, which, in addition to cleaning the injector nozzle, carries out its comprehensive diagnostics, showing the mechanical wear of the needle, the actual performance of the injector, etc.
If professional washing of the injector does not solve the problem of injection of the fuel mixture, then a reasonable solution would be to replace the injectors with new ones.
Replacing injectors
Repair of injectors VAZ 2110–2112
Repairing injectors means cleaning the product and replacing the O-rings. Simple measures to restore the functionality of the injectors can significantly increase the car’s power and make cold starts easier. Injector repair is possible in the following cases:
- there are no visible deformations on the body;
- the nozzle has not yet exhausted its service life;
- the car owner wants to optimize the operation of the power unit.
In all other cases (cracks and deformations, long service life), it is recommended to replace the nozzles with new ones.
How to blow out and clean oil molds
On cars of the tenth family, injector cleaning may be necessary after 40–50 thousand kilometers. In this case, it is best to carry out the procedure yourself, since you can always observe for yourself the true condition of the motor and its elements, and also save a significant amount on service station services.
Many drivers prefer to use the simplest method of cleaning injectors - fuel additives. Special liquids, along with gasoline, are poured into the tank and pass through all elements of the fuel system, cleaning them. This measure is justified for new cars in which the degree of pollution is at a minimum level. But additives will not be able to properly clean injectors and other elements of the system.
Video: a simple way to clean injectors using a repair kit
Which indicates possible problems with the injector
Let us immediately note that there can be many reasons for unstable engine operation, ranging from a clogged fuel filter, a broken fuel pump, a failed spark plug or a faulty coil, to loss of compression, problems with the timing belt, etc. Along with this, one of the main signs of injector malfunction is difficulty starting the engine, especially when cold, as well as gasoline or diesel consumption (depending on the engine type), which increases noticeably. It is also necessary to note the unstable operation of the internal combustion engine in idle mode, similar to the so-called “triple” of the engine.
When driving, it is possible that one or several symptoms may occur quite frequently:
- presence of jerks, very slow reactions when pressing the gas pedal;
- obvious failures and loss of dynamics when trying to accelerate sharply;
- the car may jerk while driving, when releasing the gas, and also after changing the load mode on the engine;
It must be added that such a malfunction must be corrected immediately, since problems with the injector negatively affect not only the service life of the engine and transmission, but also overall traffic safety. In a vehicle with faulty injectors, the driver may experience serious difficulties when overtaking, on steep hills, etc.
Signs of injector failure
1. The operation of the engine starting elements slows down, which is especially pronounced in cold weather.
2. The occurrence of dips and some twitching of the car at the time of acceleration or change of transient modes.
3. Poor dynamics and reduction in engine power.
4. The amount of fuel consumed increases.
5. When idling, the car engine may run unevenly.
To avoid untimely car repairs, you should promptly check the performance of the injectors.
Self-check of injectors
Let's start with the fact that automobile injectors are divided into several types, of which two types have found widespread use at different times: mechanical injectors and electromagnetic (electromechanical) injectors.
Electromagnetic injectors are based on a special valve that opens and closes the injector to supply fuel under the influence of a control pulse from the engine ECU. Mechanical injectors open as a result of increased fuel pressure in the injector. Let us add that modern cars often have electromagnetic devices installed.
To check the injectors with your own hands without removing them from the car, you can use several methods. The simplest and most affordable way to quickly check injection nozzles without removing them from the car is to analyze the noise emitted by the engine during operation.
Repair
Before removing the injectors from the dismantled rack, it is advisable to check their functionality. To check you will need:
- four identical containers,
- tester,
- wires.
Functionality check
- Connect the gasoline supply and drain hoses and the power connector to the rail with injectors.
- Place the rack over the measuring cups.
Place the rack over the measuring cups
The shape of the cloud should be approximately the same for all nozzles
After the war, Germany received a ban on the development of injectors for aircraft engines. And engineers began adapting direct injection systems for passenger cars, discovering another important advantage compared to carburetors - efficiency.
Vladimir Berestenev
Replacement or flushing?
Some problems can be eliminated by cleaning and flushing. Others are “treated” only by replacement.
Table: problems with injectors
Malfunction | Remedy |
reduced performance | flushing, replacement if flushing fails |
leakage | flushing, replacement if flushing fails |
increased productivity | replacement |
valve sticking | replacement |
unstable valve sticking | flushing, replacement if flushing fails |
overestimated or underestimated winding resistance | replacement |
In these cases, flushing is not a panacea. This method should be used taking into account the mileage and quality of service during operation.
During operation, the injector nozzles inevitably become coked and clogged with resinous deposits. The picture is aggravated by low-quality fuel, which can introduce additional pollutants.
How to check the power supply to the injectors
This check is carried out if the injectors themselves are working, but any of the injectors do not work when the ignition is turned on.
- for diagnostics, the connector is disconnected from the injector, after which two wires need to be connected to the battery;
- the other ends of the wires are attached to the injector contacts;
- then you need to turn on the ignition and record the presence or absence of fuel leakage;
- if fuel flows, then this sign indicates problems in the electrical circuit;
Another diagnostic technique is to check the injector using a multimeter. This method allows you to measure the resistance on the injectors without removing them from the engine.
- Before starting work, you need to find out what impedance (resistance) the injectors installed on a particular vehicle have. The fact is that there are injection nozzles with both high and low resistance.
- The next step is to turn off the ignition and also reset the negative terminal from the battery.
- Next you will need to disconnect the electrical connector on the injector. To do this, you need to use a screwdriver with a thin tip, with which you need to unclip a special clip located on the block.
- After disconnecting the connector, switch the multimeter to the desired operating mode for measuring resistance (ohmmeter), connect the contacts of the multimeter to the corresponding contacts of the injector to measure impedance.
- The resistance between the outer and central contacts of a high-impedance injector should be between 11-12 and 15-17 ohms. If the car uses low resistance injectors, then the indicator should be from 2 to 5 Ohms.
Sequence of replacement work
To replace the injectors, follow these steps:
- Disconnect all wires from the battery.
- Next, separate all the mounting brackets holding the engine guard in place.
- Proceed to remove the air filter on which the hoses are attached. Disconnect the hose from the device responsible for reading the gasoline pressure, the block from the idle air regulator. Keep in mind that it is held in place by a clamp. Next, disconnect the block from the wires, folded in the form of bundles.
- Now you need to carefully unscrew the two bolts located in the ramp mount. There are flat washers under the bolt heads. Therefore, in order to avoid losses, the excavation must be done using tweezers. Now unscrew the mounting screw used to hold the tubes through which the fuel passes. Carefully remove the holder itself so that the spring washer does not get lost. Next, the fuel rail is carefully moved along the injectors until it completely exits the holes in the engine pipe. To avoid breaking them, carefully remove the ramp from under the receiver. The slightest carelessness when performing this work will lead to catastrophic consequences and costly repairs.
- Remove the injectors from the ramp using a slight rocking motion. To ensure that as little dirt as possible gets on the parts, the already removed injectors are covered with a cloth, and the place where they were in the car is hidden under any material. The main thing is that there are no large gaps.
Comprehensive diagnostics of the operation of injectors on the ramp
For such a check, the fuel rail will need to be removed from the engine along with the injectors attached to it. After this, you need to connect all electrical contacts to the ramp and injectors if they were disconnected before removal. It is also necessary to return the negative terminal of the battery to its place.
- The ramp must be placed in the engine compartment so that a measuring container with a scale can be placed under each of the injectors.
- It is necessary to connect the fuel supply pipes to the ramp and additionally check the reliability of their fastening.
- The next step is to turn on the ignition, after which you need to crank the engine a little with the starter. This operation is best performed with an assistant.
- While an assistant rotates the engine, check the efficiency of all injectors. The fuel supply must be the same on all injectors.
- The final step will be to turn off the ignition and check the fuel level in the containers. The specified level must be equal in each container.
In addition to self-checking, you can use the injector diagnostic service at a car service center. This operation is performed on a special testing stand. Testing an injector on a bench allows you to accurately determine not only the efficiency of fuel supply, but also the shape of the torch during fuel spraying.
Replacement or cleaning?
In order to understand what needs to be done with the nozzle, change it or simply clean it, it is better to diagnose them on a special stand. Under such conditions, you can test it in operation under different pressures, and also visually see how tightly it closes, and whether it is “snotty.”
If any of the injectors needs to be replaced, then you should buy a new one with exactly the same part number as the old one. Also, during installation of cleaned injectors, all O-rings should be replaced (2 pieces on each injector - approx.).
Installation is carried out strictly in the reverse order, similar to the removal procedure.
Video about cleaning injectors
Attention! When working with injectors, observe all fire safety measures, since gasoline vapors are highly flammable and pose a high fire hazard.