How to repair diesel injectors. Installation and repair of diesel injectors

Sooner or later, everyone is faced with a significant increase in fuel consumption and a drop in engine power. There are times when the car refuses to move and the sprayers may need to be replaced.

The easiest way is to take the injectors to a diesel service center, but then you will have to pay some money. This will be the most correct method, but sometimes a broken car is not able to travel 200 km to the nearest service station. Therefore, the best solution would be to repair diesel injectors yourself. The article will help you avoid mistakes; it takes into account the main nuances and difficulties of repairs.

Remember that the usual replacement of a nozzle in an injector at the level: unscrew the nut, replace the nozzle, tighten the nut, can be fraught with great danger. As a result, even when using reliable nozzles, you will end up with a nozzle whose quality is several times worse than what it was before the replacement.

Injector repair technology

We will not discuss cases with low-quality or defective atomizers here. The main conclusion is that if after the repair you do not check the result obtained on a special stand or a simple device that can replace it, an amateur replacement is doubtful.

Repairing most diesel injectors involves replacing the nozzles, since these are the elements that most often fail. Sprayers often wear out the body and melt the tip. Also, the reasons for the need for repair may be the narrow diameter of the injector nozzle and one-sided wear of the needle.

First you need to check the injectors on the stand to make sure there are any malfunctions. If the repair is carried out in a garage, then the nozzle must be carefully secured in a vice and the nozzle must be dismantled.

The difficulty is that the injectors will have to be disassembled and reassembled several times. Also, the main point of the entire process of replacing the sprayer is to keep the parts and the entire working surface absolutely clean.

Repaired injectors must be checked on a special stand. This is the only way to make sure that the product is not pouring but spraying diesel fuel.

How is the replacement made?

Each car model and the engines used inside were developed in their own way, so they have a number of design differences from all analogues. If a diesel injector is completely out of order, it is necessary to completely replace it, using instead of the damaged product a model that is ideal for your car. After this, you can replace it in the following order:

the engine cover is removed, the injectors are freed from the tube intended for draining fuel and from the power supply;
disconnect the fuel pipes;
unscrew the bolt securing the injectors;
remove injectors and rings;
install a new product and reassemble in reverse order.

Sometimes diesel engine injectors stick to the surface, but they cannot be removed roughly. Instead, use special aerosols that soften the contact area. If you are not sure which model is best to choose for your car, take advice from experts.

Design and principle of operation of diesel injectors

(Fig. 1) shows the cross section of the nozzle. All of them (except the newest ones) have a similar structure and fuel supply processes.

Picture 1

Figure 2

The injection pump supplies fuel under pressure to the nozzle fitting, from where it enters cavity “A” of the nozzle through a system of channels. There is nowhere for the fuel to move further, since the path is blocked by the nozzle needle (1), which is pressed by a spring (9). The injection pump continues to supply fuel, the pump raises the pressure to the level at which the fuel is able to overcome the force of the spring, thereby lifting the nozzle needle above the seat (Fig. 1, b).

Diesel fuel enters the cylinder, the pressure drops, as a result of which the needle sits on the seat, locking the system. When the injection pump continues to supply fuel, the process repeats.

After the injection is completed, the system must close. If it does not close, then in the next stroke the fuel will be supplied not when the pressure in the system rises to the set value, but at any moment (or, more precisely, when the pump just starts supplying fuel).

As a result, the engine operates harshly with shocks, and the motor may refuse to accept the load. In addition, combustion products may enter an unlocked system. This may cause the sprayer to fail.

Intermediate pusher - the most common injector failure

When a lateral force occurs that presses the needle against the sprayer body, the intermediate pusher (10) fights it. It relieves the needle from the possible impact of a bent spring. The intermediate pusher is located in the spacer housing (3). But it happens that the cause of the lateral force is the development of the pusher itself.

When replacing nozzles, you should always be prepared for the fact that the new product will leak. If this happens, then repeated reassembly will be required to turn the spring over or replace it. Or you will have to replace the pusher, and in rare cases even the injector body.

Everything else about the injector is pretty simple. Since the needle in the nozzle is not sealed, some of the fuel seeps into the gap between the nozzle body and the needle and enters cavity “B”, where the spring (9) is located. If you do not remove fuel from there, then as soon as the cavity is filled, the atomizer needle will lose the ability to move, resulting in the injector being “locked.”

In order to remove leaked fuel there is a “return” channel (7). The adjusting washers (8) are responsible for adjusting the opening pressure of the spray needle. The entire structure is tightened with a nut (4). There are no gaskets inside the nozzle, so the tightness of the joints can only be ensured by clean processing and precision of the joining surfaces.

Replacing nozzles

So, here we come to the process of replacing nozzles. Throughout the presentation, I adhered to the idea that you have a stand or apparatus that can replace it, on which, after the work has been done, you can test the injectors.

When doing any work related to fuel equipment, the main rule must be observed: cleanliness. Please note that cleanliness must be observed not only during direct disassembly of the injector, but at all stages, starting with the removal of injectors from the engine.

What to do if the engine on a VAZ-2114 is malfunctioning

To understand the causes of malfunctions in the VAZ-2114 engine, you need to know its configuration. He has:

there are eight valves in the cylinder head;
1.6 liter internal combustion engine with 16 valves.

Experts advise that at the first signs of tripping, immediately check the functioning of the spark plugs. To do this, carry out the following steps:

One by one, pull off the high-voltage wires from the cylinders. Pay attention to changes in engine operation: if there are no changes, the cylinder does not work.

The next step is to check the spark in the ignition system. This procedure is also simple:

The first step is to remove the tip from the high-voltage wire.
While the car engine is running, bring the wire from the cylinder head (ground) to the “break” position.
Check for a spark between ground and wire:
If there is no spark or the spark is too weak, then the ignition system is faulty.

But the following situation also happens: the spark is powerful, but malfunctions are still heard in the engine. This means that the time has come for the next step of testing - to measure compression in the cylinders, preferably in all of them at once. If the cylinder is operating correctly, there should be no difference in the pressure gauge readings (minor deviations are allowed). If the cylinder is faulty, there will be no or very weak compression.

A malfunction in the cylinder may be due to one of the following reasons:

cylinder head gasket is broken;
exhaust valve burnt out;
piston rings burst;
The piston itself burned out.

If you are unable to independently identify the reason that the VAZ-2114 engine is malfunctioning, you definitely need to do computer diagnostics. This can be done in two ways:

On a special computer stand.
Using a portable scanner (for example, ASKAN).

An experienced motorist himself will be able to figure out the malfunctions of the VAZ-2114 engine, but if he does not have sufficient experience, then it is best to contact qualified specialists at a service center for servicing cars of this model.

Preparation for repair

It often happens that owners introduce debris into the threads and install the nozzle in place. Then, after a year or more, when you need to unscrew the injector, if you try hard to rip it off, a piece of the cylinder head may break off.

First of all, you need to thoroughly coat the upcoming surgical field, especially the head in the area of the channels and the nozzle body. This is very important, since sand and dirt can get into the channel when removing the injector, which can then damage the threads and damage the injector seal.

The second point is extremely important in order to achieve a good result and is that immediately after unscrewing the high-pressure tube from the nozzle, be sure to cover the nozzle fitting with a clean and tight cap. At the same time, you don’t need to console yourself with the thought that the nozzles will be replaced anyway, so you don’t have to worry too much about cleanliness. The smallest debris that ends up in the nozzle fitting during testing on the stand will drive the fuel inside, as a result, the spray needle may jam.

Then there are only two options for the development of events:

If you have not yet changed the atomizer, then you have deprived yourself of the opportunity to see why your old atomizers were bad.
Secondly, new nozzles will need to be cleaned (this procedure is not always successful).

Conclusion - the nozzle cavity must always be protected from dust and debris (and even tobacco from your pocket).

The price of a mistake

The Bosch QualityScan application for a smartphone will allow you, after scanning the QR code on a repaired injection pump or injector, to see all the details of the restoration of the unit, including a list of replaced parts.

Before sinning on the power system, it is necessary to conduct a full engine diagnostics. But with a diesel engine, this is not so simple (ZR, No. 9, 2017). Incorrect operation of the injectors or injection pump may be caused by malfunctions of other engine systems. They must be identified before removing the fuel components, otherwise you can make your life much more difficult.

Removing injectors on a high mileage engine is a whole story. They often turn sour in their wells. Even a professional runs the risk of imperceptibly deforming its body when removing the nozzle. And this will put an end to its correct operation and the possibility of repair. It will be very disappointing (and costly!) if an otherwise serviceable node dies for this reason.

Removing and installing the injection pump also requires experience, because you need to at least correctly set the marks on the timing mechanism. In addition, if you repair a faulty fuel component, but do not identify the true culprit of the problem, the problem will repeat itself - and this will mean new expenses for diagnostics and repairs.

Unscrewing parts

It is best to remove the high-pressure pipes in a package together with ties (if the engine design allows this). This way, during the assembly process, you won’t confuse how everything was originally. If it is not possible to remove the tubes in a bag, then mark the fitting of the first cylinder on the pump. Then mark the tubes themselves in the order in which they stood. As life shows, this can save a huge amount of time and nerves.

Location of protective caps

Removing the “returns” will not be difficult. True, on cars from Japanese manufacturers, before you begin to loosen the return nuts, you need to put protective caps on the fittings. In order to remove the ramp itself, the caps will have to be removed, but then do not forget to put them on immediately.

But most often, the injectors are screwed into the cylinder head housing. In order to unscrew them, do not try to use an open-end wrench. Even if you managed to do this without damaging the nozzle, not everyone succeeds in screwing it back in at the right moment without damage.

Head for unscrewing diesel injectors

Almost all injectors have a hexagon of “22”, “24” or “27”. In order to unscrew them, elongated socket heads are quite suitable. It is much more convenient to do this work with twelve-sided heads. If it is not possible to purchase elongated heads, you can get out of the situation in this way: cut off its hexagonal part from a regular head and weld it to a piece of pipe at one end, and weld the mating part for the knob at the other end.

There is no need to unscrew the nozzles right away, first you need to slightly shake it in the thread after tearing it off. This is done in order not to immediately damage the threads in the head or the head itself, since during previous intrusions dirt could have been introduced into the channel.

Do-it-yourself washing

First, let's consider the most acceptable option for the car enthusiast: washing the injectors without removing them from the car. To carry out this procedure you will need the following things:

Wynns flushing fluid;
empty plastic bottle with a capacity of 1.5 l;
rubber hose 1.5 m long;
2 nipples for car wheels;
automobile compressor;
injector filter, 1 piece;
steel hose clamps, 4 pieces.

Flushing sequence

Before you start washing, you will have to assemble a simple washing device that will work like an IV for the patient.

The rubber hose is cut into two parts. The end of the first hose mat is put on the ramp fitting. A filter from the injector is connected to the second end of this half. Injection filter for fine fuel purification, connects to the bottle
A pair of holes are drilled in the cork and bottom of the bottle into which wheel nipples are installed. The nipple is unscrewed from the nipple installed in the bottom, and then the end of the second half of the hose is connected to it. And the other end of this hose is connected to the outlet of the injection filter. Nipples for car wheels that will be installed in the holes of the bottle
The result is the design shown in the photo below. Homemade flushing system for Common Rail injectors, made from a bottle
Now you need to open the fuel tank of the car (this is done in order to completely relieve the pressure in the fuel system).
Fluid for flushing is poured into the bottle, then a car compressor hose is connected to the nipple in the neck and secured with a clamp. Flushing fluid for injectors from Wynns is the best choice for self-flushing
The compressor turns on. The pressure should not exceed 3 atmospheres.
The car starts and idles until all the flushing fluid is used up.
When the engine stops, allow it to cool for 30 minutes. After this, the remaining flushing liquid is poured into the bottle, and the whole process is repeated until the engine stops again.

Disassembling injectors

So, the injectors have been removed. Now we immediately begin to remove the sealing washers from the nozzle channels, or rather their remains and general debris. Removing washers often takes a long time.

Injector and glow plug

As a rule, normal washers should simply be removed with a hook, but sometimes you have to come up with homemade devices for this (for example, screw a tap into them and pull it).

Under no circumstances should you try to cut the washer in the channel with a chisel. You will definitely damage the end of the channel, and correcting such nicks will require removing the cylinder head. You should not try to solve the problem of a damaged end by installing tricky washers.

The engine will clean itself. In this case, you can check the condition of the glow plugs and their control system. With the injectors removed, the operation of the spark plugs is clearly visible.

Do not forget to plug the nozzle channels with oily rags, and the engine on top with polyethylene so that no water gets into the channels.

After cleaning the channels to completely remove debris from them, you must crank the engine with the starter for 10-20 seconds.

Inspection and diagnostics of injectors

First, the injector needs to be diagnosed. To do this, you will need a diagnostic stand or a special device. The timeliness of operation at a specific pressure, as well as the uniformity of the supply of diesel fuel, the shape of the spray of fuel and tight closure are considered the main points of evaluation.

Fuel must be supplied to the cylinder only at a given pressure. Any deviations are not acceptable. Fuel should not leak out ahead of time (otherwise the injector will overflow). After fuel is supplied to the cylinder, the pressure in the nozzle must remain in order to release excess diesel fuel into the return line.

Fuel should ideally be sprayed in the form of an even cone without deviations to the sides. Spraying should be done in the form of an aerosol and not in streams or drops.

Listen to how the injector fires. By comparing its sound with the sound of one that is guaranteed to work, you can quickly understand where the problem is.

How to check the performance of a diesel injector

Having removed the injectors, first of all you need to check their performance and make sure that the previously passed verdict was not erroneous. The main criteria for assessing the performance of nozzles:

when supplying fuel, the injector should open only under the specified pressure;
before the nozzle opens, leakage from the sprayer is unacceptable;
During fuel injection, jets and drops are not allowed;
the spray pattern should be smooth, there should be no deviations (Fig. 2);
After stopping fuel injection, pressure should remain in the injector for some time.

They also talk about the characteristic sound of an injector firing, but the sound should not be considered an objective parameter for evaluating an injector. This is a secondary indicator. If it turns out that replacing the nozzles is really necessary, then we put protective caps on the nozzles and begin to prepare the workplace.

Main types of injectors used in this system

The Common Rail system uses different types of parts of this type. They differ in both design and performance characteristics. We list the most popular models.

Piezoelectric

The vast majority of engines with Common Rail systems use piezoelectric injectors, since they are considered advanced and have many advantages.

The actuator mechanism of the piezoelectric injector is based on a compact piezoelectric element

As the name suggests, the actuator is based on a piezoelectric element. Using such an element provides a number of advantages:

an injector with a piezoelectric element switches 8 times faster compared to analogues made on the basis of electromagnetic valves;
the needle in it weighs 70% less;
such a part can inject fuel several times during one engine stroke;
the fuel injected into it is very accurately dosed.

Electromagnetic

Electromagnetic injectors are used primarily in gasoline engines. The needle in it is driven by a spring and an electromagnet, and during one engine stroke the part can produce only one fuel injection. The design of this device can be seen in the figure below.

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Common Rail electromagnetic injectors are used primarily in gasoline engines

It should be noted that in terms of fuel dosing accuracy, the electromagnetic one is significantly inferior to the piezoelectric one. This indicator directly depends on the type of control system. For example, if a car is equipped with a modern ECU, the accuracy of gasoline dosing increases by 10–12%. There is a certain error in the timing of electromagnetic injectors. For example, an injector needle can hold the nozzle channel open for 2–2.5 ms with an error of 6%. This figure is very far from ideal.

Repair of diesel injectors

Necessary tools and equipment:

two baths with clean diesel fuel;
necessary keys (usually two);
knife;
device for fixing the nozzles (if not, use a vice).

Anything unnecessary will interfere with your work. If the garage does not have a special device for fixing the injectors during repairs, you will have to disassemble it in a vice.

Injectors from Japanese cars, in which the return flow is through a ramp, should never be clamped in a vice. When clamped, the edges of the sealing surface under the “return” are crushed (Fig. 3). Such nozzles can be disassembled by placing them in a spanner, which is clamped in a vice (Fig. 4).

Figure 4

Figure 5

But injectors from German manufacturers must be disassembled in a vice without harming your health. There are 2 reasons why open-end wrenches should not be used to disassemble and repair an injector:

It's quite inconvenient.
The union nuts of the injector housings of some engines (for example: Mercedes OM601,602,603) almost always crack. When trying to assemble or disassemble them, the nuts are damaged by the open-end wrench. But these parts are quite expensive, and they are not so easy to buy.

Therefore, to disassemble the injectors, it is advisable to use the same elongated head as for removal from the engine.

Loosen the union nut, then screw it together by hand. Often it can curl up with the atomizer that is stuck to it. The sprayer, after the nut is removed, can be knocked out with a suitable rod, and the cavity of the nut can be cleaned with a brush for cleaning the battery terminals.

To perform this work, you need to move a couple of meters away from the clean area. The nut needs to be washed in the first bath - it will be used for initial rinsing. After the nut, put it to the side on a sheet of paper. Now we remove the intermediate housing, rinse it in a clean bath, drain the injector body, which is clamped in a vice, with fuel and put the intermediate housing in place, do not touch anything else.

We take a new sprayer, without disassembling it, and rinse it in clean fuel. After rinsing, you need to remove the intermediate housing or atomizer (as well as all parts of fuel equipment) from the bath so that the flowing fuel takes away with it all the dust particles from the mating surfaces (Fig. 5 and 6).

Figure 6

Figure 7

We put the sprayer in place and tighten the union nut. Now you need to check on the stand what happened. It happens quite often that when, before replacement, a nozzle from a worthy manufacturer was installed on the nozzle, we replaced it with an equally worthy one. If other parts of the nozzle are not too worn out, then it may turn out that after replacing the nozzle the nozzle will immediately work as it should, then no further adjustments will be required. If this miracle happens, you can immediately close the nozzle fitting with a cap and finally check the tightness of the union nut.

The fact is that if you do this procedure several times every day, then you involuntarily do not pull the union nut very hard - since it takes a minute to disassemble again. Unfortunately, it doesn’t always work out the first time: most often the pressure doesn’t match and the sprayer leaks. You shouldn’t hope that it’s leaking because we didn’t disassemble it and wash it out of conservation the first time. These hopes are only valid if the atomizers are preserved by immersion in a gelatinous mass, but this is rare.

Typically, all modern sprayers are preserved by the manufacturer themselves, moreover, in a special oil or in an inert environment. And I am sure that we cannot do anything cleaner than Bosch or Delphi cleans their parts before packaging. So, the reason for poor spray is most often the wear of the intermediate pusher (position 2, see Fig. 1, a) or a deformed spring. Sometimes reversing the spring in the housing can help, but usually replacing worn parts is necessary.

DIY Delphi injector repair

The biggest drawback of Delphi injectors is that they are afraid of dirt or debris. If there is severe contamination, they begin to dump fuel into the return line. The solution is to repair it, namely disassemble, clean or change the valve. More details

Thus, the procedure for replacing the atomizer will turn into a series of assembly, disassembly, and checks. You will have to repeat the same operations until you achieve the desired result. Finally, we have achieved the desired result; we are satisfied with the operation of the injectors and can be installed on the engine.

No need to hurry! We remember that the nozzles are sealed with special disposable washers, the task of which is not only to seal the nozzle channel, but also to remove heat from the nozzles, thereby preventing them from overheating and coking. If we don’t install new washers, we can easily destroy the new nozzles in the first half hour of engine operation.

On injectors from Japanese manufacturers, the washers sealing the return ramp are disposable. On engines of different designs, the return seal washers are very similar. They are almost indistinguishable from each other, but installing a foreign washer or a washer from a strange manufacturer always leads to return leakage. Therefore, when you select return seal washers, you need to find out the possibility of lateral displacement of the washer on the injector when tightening, and also make sure that the fuel discharge channels can be blocked or, conversely, not sealed.

Before you start screwing in the injectors, you need to make sure, by turning the crankshaft with the starter, that no water or other debris has entered the cylinders, and you can also look at the oil dipstick.

If everything is in order, then you can screw in the injectors; first, the threads on the body must be lubricated with graphite or copper grease, and tightened with a torque (6-7 kg.m.).

However, there is one detail: you always need to screw the nozzle into the channel only with your fingers, if the nozzle does not go, then you need to clean the threads, on some machines it is very easy to ruin the pre-chamber by screwing the nozzle in the wrong way, by the way, if the nozzle is screwed in tightly, then most likely it has gone it's not threaded.

Do-it-yourself flushing of the diesel fuel system

The appearance of the first symptoms of injector contamination requires the car owner not only to diagnose the malfunction, but also to carry out a set of measures to flush the fuel system.

The future expenses of the car owner depend on the timeliness of this work. Chronic contamination leads to breakdown of expensive parts and the need to replace them.

Self-cleaning of the fuel system of a diesel engine is most often done using special additives that are added to the fuel tank, mixed with fuel and provide high-quality cleaning of various “garbage”.

After using the additive, you can use the car as usual, being confident in the effective operation of the product.

The flushing composition is mixed with fuel, passes all the way through the diesel fuel system, is supplied to the injectors and cylinders, where it burns under pressure.

To get results, it is advisable to give preference to products from well-known brands.

Saving in this matter can lead to a lack of results or even greater contamination of the system.

Experts note that this method is ineffective, because it will not be possible to remove 100% of the contaminants.

But the additive copes with a certain percentage of “garbage”, eliminating the main signs of a malfunction - increased fuel consumption, decreased dynamics and a drop in engine power.

Good results are achieved by regular use of additives that perform a preventive function. As a result, the fuel system remains clean for a long time, and there is no need to flush it at a service station.

If the car owner has not maintained the system for a long time, it is unlikely that it will be possible to remove stubborn dirt. In such a situation, it is better to contact a service where cleaning is carried out using special equipment.

It should be noted that there are a number of other methods for cleaning diesel injectors. One of them is the dismantling of products for direct cleaning by simulating work.

This option is suitable for old-style engines, but in the case of new diesel engines it is dangerous. The main risk is the difficulty of dismantling the nozzle. Even if the latter can be removed, there remains a high risk of damage to the device.

As a result, you will have to buy a new part, the cost of which will cover the savings of replacing it yourself several times.

There is another cleaning option - using washing liquid.

Below we will consider the principle of performing the work using the example of a composition from the manufacturer Wynns.

Algorithm of actions:

Take a pair of gasoline-resistant hoses with a length of 70-80 cm. The diameter of one tube should be 0.8 cm, and the second - 1.0 cm.
Remove the original tubes from the injection pump and put the purchased products in their place. Place the second edges of the hoses in a container with the product poured into it.
Place a standard Zhiguli filter on the thicker tube that supplies fluid to the injection pump. Be careful when doing this - the hose must reach the bottom of the container to prevent air entrapment. In this case, the bottle itself must be secured under the hood.
Start the engine and leave it running for 15 minutes at idle. After this, press the accelerator pedal several times, wait another 3-4 minutes and turn off the engine.
Wait 15-20 minutes until the liquid has completely cooled and the deposits have left the surface.
Carry out the procedures discussed above until the rinsing composition runs out.

Monitor the mixture carefully. You cannot allow a diesel engine to stall due to lack of fluid. On many modern cars, fuel-cooled electronics are installed in the internal part of the fuel injection pump.

If there is a shortage of flushing fluid or fuel, it may suffer. To optimize flushing, you can make a special coil and lower it into a bucket to ensure high-quality cooling of the liquid.

After the composition has been developed, return the fuel pipes to their original places and start the engine. As soon as the diesel engine's operation returns to normal, turn it off.

The work of self-flushing the fuel system is completed, and the car is ready for use.

Be careful and remember the dangers of the working fluid. It helps to wash your hands, but after using it, it is advisable to rinse your skin with clean water and lubricate it with cream.

If the fuel injection pump of the car is very dirty, it is recommended to take two cans of liquid and then proceed according to the algorithm described above. Empty the contents of the can to the end so that the engine does not stall.

After this, turn off the diesel engine, and the next day perform the same manipulation, but using the second can.

Upon completion of the work, all that remains is to return everything to its place.

Assembly and testing of injectors

Reassembly shouldn't be a hassle, but that's only if you didn't get carried away and marked all the tubes and fittings when removing them. Just a few tips. Before installing the high-pressure pipe, you need to wash the outside and flush the inside with fuel. And yes, do not neglect to reinstall the clamps that collect the tubes into a bag. These clips are not intended for aesthetics. They prevent vibration. Tubes without clamps break very quickly (it’s like they’re being cut with a knife).

Well, that seems to be it, you can remove the air from the equipment and try to start the engine.

How to check injectors after repair

What is the best way to check the performance of the injectors? Undoubtedly, it is best to use a stand to test injectors. This stand can be a very complex electronic one, costing several thousand dollars, or very simple, one might even say primitive in the spirit of the fifties (Fig. 7) or homemade (Fig. 8).

Figure 8. Stand for testing diesel injectors

Figure 9. Homemade test bench

Any of them can be used with a lesser or greater degree of convenience. I think even in your smallest city there are diesel garages that have stands. We need to find it, because we know how to negotiate.

But it happens that your diesel is the only one in the area. Then we try to make the stand ourselves. You can make a homemade stand from a KAMAZ tractor pump or a ship pump; in extreme cases, you can adapt your car’s fuel injection pump for testing.

To do this, you need to make a tube - a tee, one end of which will be connected to one of the high-pressure fittings of the injection pump, the other end we will attach the nozzle, and on the third we will attach a pressure gauge of 200-300 atmospheres, of course more is possible, but this one will do at the end.

First, we crank the engine with the starter until the injector starts firing, and then, without leaving the ignition on, we crank it by hand. Of course it’s painful, but if there’s no other way out, it’ll do.

About the injector opening pressure

During the compression stroke, an air charge flows from the cylinder into the combustion chamber at enormous speed. In the combustion chamber, due to its shape, at this moment a directed vortex appears, and fuel is injected into this vortex.

There are different nozzles and different fuel injection pressures, depending on the compression ratio and the design of the combustion chamber; the shape and speed of the vortex are different. Designers establish recommended, permissible injection pressure values for each engine.

As a rule, the set values must be observed with an accuracy of 5-10 kg.cm2 within the set of nozzles. When reassembling the nozzle, the injection pressure must be set 10-15 kg.cm2 more than required, since in the very first minutes of the nozzle operation there will be some shrinkage of the moving parts and, accordingly, a decrease in the set pressure will occur.

It is necessary to note the property of rotary fuel pumps from LUCAS - these pumps have strict requirements for the accuracy of injection pressure adjustment within the set of injectors. In engines with such fuel pumps, searching for a faulty injector using the shutdown method is impossible. Since the engine will immediately stall due to the fact that the fuel supply to the remaining injectors will stop.

Basic faults

The most common injector malfunctions are as follows.

Injector knock

One of the most common malfunctions is injector knocking. The injector is constantly under load and becomes dirty - this is the source of sounds similar to high-frequency knocking (chirping).

The consequences of the appearance of such sounds are as follows.

reduction in engine power;
dips when pressing the accelerator pedal;
floating idle speed;
increased content of toxic substances in exhaust gases.

This problem can be corrected by washing or replacing the injectors.

Fuel leakage through injectors

This malfunction, typical of diesel engines, most often occurs due to wear of the injector washer. Less commonly, the cause of the leak is the connection between the fuel pipes and the injector.

The procedure for identifying and eliminating the source of a leak is as follows:

The nozzles and their connections with the tubes are wiped dry.
Areas of possible leakage are treated with ordinary chalk.
The starter cranks for 3–4 seconds without starting the engine.
Leak points will be clearly visible on white chalk.
If the housing leaks, the nozzle is replaced with a new one.
If a leak is found in the area between the head and the injector, the copper O-ring is replaced.

If the housing allows fuel to pass through, the injector is replaced with a new one.

No fuel supply

If there is no fuel flowing into the injectors, the cause should first be sought in the high pressure fuel pump. The injection pump belt should be checked for breakage or sagging.

Then you need to remove one of the hoses coming from the injection pump, place its end in a container and turn the starter. If fuel does not flow, the pump is faulty.

Sometimes fuel may not flow into the pump itself. In this case, the hose at the inlet to the injection pump is removed and checked in the same way. If fuel does not flow, the problem should be looked for in the gas tank pump.

Other faults

Among other malfunctions, it is worth highlighting the following.

The intermediate washer located between the spring and the nozzle wears out and becomes bent. The needle does not rise high enough, and the fuel flows unstably.
The spring wears out and loses its rigidity. The spring is changed, or several additional washers are installed in the nozzle.
Damage to the nozzle body itself.

How to regulate the opening pressure of a nozzle at home

In most cases, the opening pressure of modern injectors can be adjusted by selecting the thickness of the spacer washer between the body and the spring. Good workshops have sets of these washers that can solve adjustment problems.

But amateurs should know that there are washers of different diameters, they are designed for different injector bodies, and come in versions with or without a hole. Washers without a hole can be replaced with washers with a hole, but the reverse replacement is not allowed. It is also unacceptable to use washers of a “non-native” diameter.

Adjusting injector pressure at home

Adjusting the nozzle opening pressure

As a rule, injectors are designed in such a way that when the washer thickness increases by 0.1 mm, the injection pressure increases by 10 kg.cm2. Quite often, when repairing injectors, you see that during previous interventions, the injection pressure was regulated using razor blades cut into small pieces, which were placed under the spring. This adjustment method is unacceptable. Firstly, thereby you get a lining of an uncontrolled shape, an uncertainty in the spring support is created, non-uniform production occurs and the occurrence of lateral force is provoked. And secondly, a chipped piece of blade can do a lot of damage inside the nozzle.

Therefore, the only high-quality solution to the problem is the production of new washers of the calculated thickness. And only in those cases, if you do it on a lathe, grinding and heat treatment are absolutely impossible, you can regulate the pressure with washers made of steel foil, they need to be placed between the standard washer and the body. If your spring rests on a non-hardened lining, then after a short time there will be nothing left of it.

Typical problem with Japanese injectors

A distinctive feature of injectors from Japanese engine manufacturers is the discharge of the “return” into a special ramp through the end of the injector. If you disassemble it carelessly, the sealing end of the injector will become deformed. Due to deformation, a hermetically sealed “return” cannot be achieved. Some begin “experiments” with tightening the ramp nuts and placing sealing washers under the nuts.

The only way to solve this problem is to trim the sealing end of the injector on a lathe. But keep in mind that only one surface of the nozzle can be corrected by facing, so the shape of the groove at the end may be deformed so much that the sealing washer can no longer cover it. Just change this nozzle.

Stupid attempts to tighten leaking or leaking returns almost always lead to deformation of the return ramp flanges. It will not be possible to achieve a seal with these flanges; they will have to be rebuilt. This is quite simple and can be done by hand sanding the tiles by placing sandpaper on them.

Source: https://diesel.dcp.kiev.ua/RemInjector.html

Cleaning

As already mentioned, it is possible to extend the service life of Common Rail injectors and avoid making repairs ahead of schedule if you periodically clean them by adding a special product to the tank. Such cleaning should be carried out every 25-30 thousand kilometers of distance traveled. If this is not done, then the entire fuel system, including the high-pressure fuel pump, may become unusable.

Many people know that repairing the entire fuel system is very important, because without a working fuel system the car will not be able to drive. You can do this cleaning of Common Rail injectors yourself. The second cleaning stage does not require removing them from the machine. In this case, cleaning the Common Rail injectors is carried out by blowing air into them under pressure, which can clear clogged nozzles.

There are such blockages when even the second option does not help, in this case the last stage of cleaning the injectors will come to the rescue. The cleaning process in the third option is based on the fact that the device is immersed in a special chamber, where, under the influence of ultrasound, all particles that clog the nozzles are destroyed. The only disadvantage of this cleaning option is that in this case you will need to remove them from the car and take them to a service station where such work is carried out.

Don’t think that you can clean completely clogged nozzles yourself. If you clean it yourself, you can completely damage the atomizer, channels or body of the device. In this case, a complete replacement of nozzles or even injectors will be required, which will have a negative impact on the driver’s wallet.

Removing injectors from the engine for diagnostics

On modern injection systems, the element is an electromagnetic device that opens upon command from the ECU to allow some of the fuel to pass through. On most cars, the injectors are installed on the fuel rail (rail). The removal process may differ slightly depending on the type and design of the internal combustion engine, and different tools may also be needed. Often, to remove fuel injectors, you need to prepare:

Screwdriver Set;
several keys;
pliers or pliers;
carburetor cleaner;
rags or suitable rags;

Now let's take a closer look at the process and answer the question of how to remove injectors on a VAZ or any other fuel-injected car. First you need to reduce the pressure in the fuel system. Many car models have a pressure regulator on the fuel rail. This regulator is a valve that needs to be pressed. As a result, fuel will flow out of the ramp and the pressure will drop.

Next, you need to remove the fuel rail on which the injectors are attached. To dismantle it is necessary to disconnect the connectors with wires that are secured using a special clamp. The specified latch is a spring clip that must be pressed. Then you will need to use a screwdriver to move the clamp along the ramp. The injectors can now be removed.

Removal is carried out by slightly turning or rocking the device, after which you need to remove the O-rings with a flat screwdriver. The rings are usually located on the body and on the atomizer. Note that after removal, the rubber O-rings of the injectors must be replaced.

Additional recommendations

Having understood the washing technology, you can make sure that it is not so complicated if we are talking only about the technical component. Selecting the necessary materials, preparing tools and creating a special device for the job is quite simple. To do this, you only need to have desire, free time and the skills to use conventional tools that are present in the driver's kit.

Cleaning injectors without removal

But with the choice of a high-quality cleaning agent, things are much more difficult, because this is a responsible task. An incorrectly selected product can damage the injectors and make them unsuitable for further use. Such an error will entail not only temporary, but also additional financial costs. Therefore, it is important not to make mistakes when choosing.

Video - Cleaning injectors through the fuel tank

Bad gasoline and a significant age of the car are the two most common reasons why fuel injectors have to be flushed.

Fuel injectors are essentially solenoid valves that, when voltage is applied to them, open the path of fuel into the intake manifold. When there is no power, the shut-off needle lowers under the action of the return spring and closes the channel in the sprayer. Over time, deposits accumulate on the nozzle seat, causing the needle to lose mobility. As a result, the seal of the injectors is broken. A sign of such a malfunction is poor starting of the engine, even when warmed up: the fuel mixture turns out to be over-rich. In addition, contamination of the nozzle holes leads to disruption of the atomization and a decrease in the total amount of fuel supplied. Because of this, when you sharply press the gas, dips appear, the engine loses power, and begins to work unstably.