It's no secret that the direct injection engine is far from new. Mitsubishi engineers became pioneers in this area. The first of the cars equipped with GDI engines were the Mitubishi Galant and Legnum sold in the Japanese domestic market. The engine was marked 4G93 and was installed on Mitsubishi Carisma, Colt, Galant, Lancer, Pajero iO, etc.

GDI engine device

Let's take a closer look at what is GDI or Gasoline Direct Injection, and in Russian - direct fuel injection, and let's figure out what it is. He came to replace the engines MPI, or Multi Point Injection(port injection), in which fuel is injected into each intake port and the mixture is formed before entering the cylinder. Meanwhile, GDI is an injection system in which the nozzles are located in the cylinder head, and fuel is injected not into the manifold, but directly into the engine's combustion chamber.

At the current stage of the automotive industry, direct injection is the most progressive type of power supply. gasoline engine.

Now many automakers produce cars with this system, but different automakers call it differently. Direct injection for Ford - EcoBoost, Mercedes - CGI, VAG concern - FSI and TSI, etc.

The fundamental differences between the operation of a GDI engine and the operation of engines with port injection are:

• fuel supply directly to the cylinders,
• the possibility of using super-poor mixtures.

The mixture is supplied under pressure, which is ensured by the use of injection pump, which develops high pressure in the fuel rail. Due to this, the nozzle opening time was reduced by 6 times (in comparison with conventional injection engines) to 0.5 ms at idle.

Direct injection reduces fuel consumption by up to 20% and reduces emissions, but engines with this system are less tolerant of the quality of the fuel used.

Mitsubishi(Mitsubishi) when creating the GDI engine, they absorbed the best of gasoline and diesel internal combustion engines. Thus, here, as in any other gasoline engine, there are spark plugs for each cylinder, but there are fuel pump high pressure (TNVD) and nozzles for each cylinder. Thanks to the injection pump, gasoline is injected through the nozzles into the cylinders at a pressure of about 5 MPa, and the nozzle performs two types of gasoline injection. Therefore, if you want to convert your car to gas, then you will need the appropriate equipment and special settings for the HBO control unit (due to the location of the nozzles, etc.).

GDI engine operating modes

GDI direct injection technology

The GDI engine is capable of operating in various modes (there are three of them), each of which depends on the load to be overcome. Consider these modes:

• Operating mode on extra-lean mixture. This mode is activated when the engine is lightly loaded. With it, fuel injection occurs at the end of the compression stroke. The air/fuel ratio in this case is 40/1.
• Operating mode on a stoichiometric mixture. This mode is activated when the engine is under moderate load (for example: acceleration). Fuel is supplied at the inlet, it is injected with a conical torch, filling the cylinder and cooling the air in it, which prevents detonation.
• Operating mode of the control system. When you press the “sneakers on the floor” from low speeds, fuel injection is carried out in stages, in two stages. A small amount of fuel is injected at the intake, cooling the air in the cylinder. An over-lean mixture (60/1) is formed in the cylinder, which is not characterized by detonation processes. And at the end of the compression stroke, the required amount of fuel is injected into the cylinder, which “enriches” the fuel-air mixture (12/1). At the same time, there is no time left for detonation.

As a result, the compression ratio increased to 12-13, and the engine functions normally on a lean mixture. Together with this, the engine power increased, fuel consumption and the level of harmful emissions into the atmosphere decreased.

And the newest GDI engines from KIA are equipped with a turbocharger, and they are called T-GDI. So the latest engines of the Kappa family reflect the global trend towards “downsizing”, which is expressed in a decrease in engine sizes along with an increase in their efficiency. For example, the 1.0 T-GDI engine from KIA has a power of 120 hp. and a torque of 171 Nm.

Features and disadvantages of GDI engines

Direct injection technology is very relevant, but it is not without its drawbacks.
So what's wrong with a GDI engine?

• Extremely whimsical to fuel, due to the use of a high pressure fuel pump (similar to diesel cars). Due to the use of high pressure fuel pumps, the engine reacts not only to solid particles (sand, etc.), but also to the content of sulfur, phosphorus, iron and their compounds. It should be noted that domestic fuel has a high sulfur content.
• Injector specifications. So, in GDI engines, the nozzles are placed directly on the cylinders. They must provide high pressure, but their working potential is low. It is also impossible to repair them, and therefore the nozzles change entirely, which brings the owners a lot of additional costs.
• The need for continuous monitoring of air quality. Therefore, it is necessary to constantly monitor the cleanliness of the air filter.
• On cars with the first generation GDI, the high pressure fuel pump (TNVD) had a short resource.
• Owners of “middle-aged” cars need to use an engine intake cleaner every 2-3 years. Basically, aerosol sprays are used for this (for example: SHUMMA).

Despite the listed disadvantages, many car owners claim that when refueling a car at proven gas stations 95-98 with gasoline (and not from Petka’s “trakhter”), timely replacement candles (original, which is extremely important) and oil, GDI engines do not cause problems even with a run of up to 200,000 km or more.

Advantages of GDI engines

So, benefits of GDI engine by reviews:

• Less average consumption fuel in comparison with engines equipped with distributed injection;
• Less toxic combustion waste;
• Greater torque and power;
• Increased service life of individual engine parts, as these engines have less carbon deposits.

The decision to buy a car with a GDI engine or not is a personal matter for everyone. But, having made a positive decision, it is worthwhile to “examine” the car in the most thorough way. If he is not killed, then you have even more food for thought, because it is extremely pleasant to drive “briskly”, but with less fuel consumption, and cause less harm. environment and your health.

An article about GDI engines - the principle of operation, features, differences from other types of motors. At the end of the article - interesting video about power units with direct fuel injection.

General information

First Mitsubishi cars with GDI motors began to be produced in 1996. Since then, the engine has undergone many changes and improvements, as the original version was far from perfect.

The peculiarity of the engine is that at low loads (uniform driving at speeds up to 120 km / h) it runs on a lean air-fuel mixture. When the load increases, there is an automatic transition to the classic injection system. This makes the car economical (up to 20% savings) and environmentally friendly.

Operating principle

A lean air mixture reduces fuel consumption, but ignition is often a problem. An overly saturated mixture of gasoline ignites easily, but excess fuel does not burn and is removed along with the processed gases, which leads to useless waste. Not to mention the fact that a layer of soot is intensively formed on the candles and valves.

The GDI system differs from the usual one in that fuel is injected not into the intake manifold, but directly into the combustion chamber, like in engines running on diesel fuel.

The principle of operation of the GDI engine:

1. Gasoline is fed into the combustion chamber under high pressure and swirling flow, thanks to the special structure of the nozzles.
2. The flow at high speed collides with the piston, after which part of it is, as it were, fixed on the body of the piston, and the other part continues to move, creating friction and acquiring the appropriate shape.
3. After that, the flow bends and moves away from the piston, increasing speed. Some particles move slowly and go in different directions, creating a flow separation.
4. As a result of this, two sections with a gasoline-air mixture are formed in the combustion chamber. In the center is a section of a stoichiometric (ordinary) flammable fuel mixture. A lean mixture area forms around it.
5. After that, ignition (with the help of a spark of spark plugs) of the area with a high content of gasoline occurs. Then the combustion process is transferred to the depleted areas.

The main differences between GDI and a conventional injection system

1. Injection is carried out under pressure from 50 atmospheres (in normal injection engine only 3 atm). This makes it possible to carry out finely dispersed directional spraying.
2. The throttle valve is located slightly further than conventional motors.
3. The fuel is fed directly into the cylinder and there the air-fuel mixture is formed. In conventional engines, fuel is fed into the intake manifold, where it mixes with the air mass.
4. The pistons have a spherical recess. With the help of this recess, the formation of a vortex and the resulting flame are controlled. The recess also makes it possible to control the formation of a combustible mixture by adjusting the amount of air mass and gasoline in the connection process.
5. There is a possibility of the formation of the most depleted combustible mixture in the cylinders. The optimal ratio of air to gasoline is 40:1 (as opposed to conventional injection with a ratio of 14.7:1), but the amount of air can range from 37 to 43 to 1.
6. The nozzles located in the cylinder head have a configuration that allows you to give the fuel flow the desired, as if twisted, shape. Thanks to this, the flow moves along a clearly defined trajectory.
7. GDI motors operate in two modes: STICH (ordinary, like other injection systems) and Compression on Lean (working at the maximum lean mixture). Switching between modes occurs automatically; when the load increases, the car switches to work with a rich fuel mixture. When the load decreases, it goes back to lean.
8. The design is equipped with a high pressure pump.

Features of injection pump

There are four types of injection pumps:

1 generation. Seven plunger fuel pumps

The first and most short-lived. Installed in Mitsubishi cars from 1996 to 1998. They do not have a pressure monitoring system and are extremely sensitive to the quality of gasoline. They cannot be repaired, and when worn (and this happens very quickly), a complete replacement is necessary.

2 generation. Three-section fuel pumps

They are a modification of the seven-plunger. Installed from 1998 to 2000. Here the manufacturer took into account past shortcomings and paid attention to their elimination. They have a regulator and a pressure sensor, in case of a sharp drop, they put the car into emergency mode. This allows the vehicle to continue driving long enough to reach the service station.

The model has become somewhat more "loyal" to the quality of gasoline and more durable.

3rd generation. Two-section injection pump

There is a pressure sensor, but the regulator is not built into the system. The drive is powered by a camshaft.

4th generation. "Tablet"

The latest and most advanced model. Relatively durable, less sensitive to fuel quality, compact and reliable. The main disadvantage is self-loosening fixing nuts. Their condition must be checked regularly, as their weakening leads to a malfunction of the system and deformation of the plates, which are quite difficult to align.

The design of high pressure fuel pumps depends on the specific model.

How important is fuel quality?

In addition to the features of the injection system itself, a thorough filtration system also affects the durability of the engine. It has 4 stages:

1. Cleaning takes place using a mesh filter in the gas tank pump.
2. It is cleaned with an ordinary filter. Depending on the brand of the car, its location may vary. The filter can be installed in the tank or under the bottom.
3. Filtration takes place with the help of a filter cup located in the injection pump fuel line.
4. The last stage of cleaning occurs at the moment when fuel is supplied from the "fuel rail" to the tank.

For example, the diaphragm valve and plungers are made with a high degree of precision, due to which the fuel mixture is injected at the required pressure. If gasoline is found to contain sand particles or other impurities, especially those with abrasive properties, the supply system will be affected by them and its operation will lose accuracy. Which will lead first to a decrease in the efficiency of the engine, and then to a breakdown of the high-pressure fuel pump.

First of all, when a problem occurs, engine power is reduced. After a while, he starts to refuse altogether. If you contact the repair shop at the first sign of a malfunction, the fuel pump can still be saved. Otherwise, it will have to be completely replaced, since it is pointless to restore badly damaged parts.

Another common GDI problem is floating speed. The reason can be both the impact of low-grade fuel and the natural wear of the high-pressure fuel pump elements.

In the process of these transitions, the machine begins to “float”. If such a deviation is detected, the car should be sent for diagnostics in order to find the exact cause of the problem.

Conclusion

GDI engines are powerful and economical, but the good is almost always the cause of the bad. In this case, it is excessive sensitivity to the slightest deviations in the injection system and fuel quality. To extend the life of the car, you should regularly replace the spark plugs (soot quickly forms on them), clean the intake manifold and nozzles.

It will not be superfluous to regularly inspect the injector and check the quality of the spray, eliminating the slightest problems at the stage of their occurrence. And, of course, it is necessary to constantly monitor the condition of the filters and change as needed.

Video about modern engines with injection:

The high pressure fuel pump (TNVD) is one of the most important components of a direct injection engine. Despite the fact that the injection pump is quite well protected (filter in the tank and at the injection pump inlet), it is nevertheless most susceptible to wear in harsh Russian operating conditions.
So far, three generations of injection pumps have been produced:
First generation, single-section seven-plunger pump. This is the most complex pump in design, where fuel pressure is created using a "drum" with 7 plungers. The precision of the parts in this pump is such that wear of even one hundredth of a millimeter leads to a serious deterioration in its performance. The resource of such a pump is small, and as a rule does not exceed 100 thousand km.

It is almost impossible to repair it, therefore, as a rule, it is replaced as an assembly with a second-generation pump. The 1st generation high-pressure fuel pumps were installed on cars for a relatively short time - from 1996 to mid-1997.
Second generation, three-section single-plunger pump. This is perhaps the most successful modification of the high-pressure fuel pump in terms of maintainability: three separate blocks ("sections") - a drive, a pump and a pressure regulator, each of which can, if necessary, be replaced without touching the rest. Fuel pressure is created using special plates, the condition of which directly affects the performance of the pump.

The third generation, the so-called "tablet". There are two modifications of this type of injection pump - with a pressure regulator located inside the injection pump, or placed in the "return" line. The high pressure block is almost identical to the 2nd generation injection pump.
The main malfunctions of high-pressure fuel pumps of the 2nd and 3rd generations arise due to untimely scheduled maintenance for replacement fuel filters fine and coarse cleaning. During normal operation, the average resource of this type of injection pump is about 200,000 km, without its repair. In this case, as a rule, the plunger pair in the pump is in good condition, mainly reed valves wear out.
Symptoms of a malfunction of the injection pump: unstable engine operation, poor traction; the engine is reluctantly picking up high revs(above 2000 rpm); when you press the gas pedal while driving, the car slows down sharply and may even stall. In this case, as a rule, on the instrument panel lights up light bulb Check Engine and diagnostic scanner gives a Fuel Pressure Fail error (code P0190). With all these signs, it makes sense to check the fuel pressure. If there is no diagnostic scanner, the pressure can be checked using a conventional digital multimeter. The signal can be removed with a voltmeter from the middle contact of the fuel pressure sensor located, depending on the design, on the injection pump or the fuel rail. In this case, the measurement must be carried out on a warm engine and D or R on. The pressure rating is for 4G15 - 2.9 volts (4.7 MPa), 4G93 - 3.0 volts (4.8 MPa), 4G64 - 3.4 volts (5.6 MPa), 4G74 - 4.0 volts (6.8 MPa), when the pressure drops below 2.6 volts, the ECU gives a command to increase the speed to stabilize the pressure. Even with a complete loss of high pressure and a malfunction of the injection pump (working only at the pressure created by the submersible pump in the tank), the ECU switches to an emergency program and increases the nozzle opening time by up to 3.2 m.sec. (MPI mode), instead of 0.51 m. sec.(GDI mode) on Idling, and does not allow the engine to develop speeds above 2000 rpm, which allows the engine to continue to work.

Mitsubishi can be called a pioneer in the mass introduction of direct fuel injection. Unlike Mersedes, which long before Mitsubishi were trying to implement direct injection in cars, simply applying the best practices from experience in the aircraft industry, Mitsubishi engineers created a system that would be convenient and suitable for everyday car use. Consider the GDI engine, the device and the principle of operation of the power system.

Basic concepts

In the article about, we found out that there are several types of fuel injection systems:

• single point injection (monoinjector);
• distributed injection on valves (full injector);
• distributed injection into cylinders (direct injection).

Gasoline Direct Injection, which means direct gasoline injection, immediately tells us what is happening in GDI engines internal mixing. In other words, fuel is injected directly into the cylinders. But what exactly are the advantages of direct injection:

The problem of the low efficiency of a gasoline engine, compared to a diesel engine, is within a small framework of adjusting the composition of TPVS. Theoretically and experimentally, it was found that 14.7 kg of air is needed for complete combustion of 1 kg of gasoline. This ratio is called stoichiometric. The engine can run on a lean mixture - about 16.5 kg of air / 1 kg of gasoline, but already at 19/1 TPVS from the spark plug will not ignite. But even a 16.5/1 mixture is considered too lean for normal operation, since TPVS burns slowly, which is fraught with power loss, overheating of the piston rings and combustion chamber walls, and therefore the working lean homogeneous mixture lies within 15-16/1. By preparing a rich mixture in the cylinders with a ratio of 12.1-12.3 / 1 and shifting the UOZ, we get an increase in power, while the environmental performance of the motor is significantly deteriorating.

Economy of GDI

The problem with conventional engines with multiport valve injection is that fuel is supplied exclusively on the intake stroke. The mixing of fuel with air begins to occur even in the intake manifold, as a result, when the piston moves to TDC, the mixture becomes close to homogeneous, that is, homogeneous. The advantage of GDI is that the engine can run very lean when the fuel to air ratio can reach 37-41/1. Several factors contribute to this:

• special intake manifold design;
• nozzles that allow not only to accurately dose the amount of fuel supplied, but also to adjust the shape of the torch;
• special shape pistons.

But what exactly is the peculiarity of the principle of operation that allows GDI motors to be so economical? The air flow, due to the special shape of the intake manifold, consisting of two channels, has a certain direction even at the intake stroke, and does not enter the cylinders randomly, as is the case with conventional engines. Getting into the cylinders and hitting the piston, it continues to twist, thereby contributing to turbulence. The fuel, which is supplied in the immediate vicinity of the piston to the TDC by a small torch, hits the piston and, picked up by the swirling air flow, moves in such a way that at the moment the spark is applied it is in close proximity to the spark plug electrodes. As a result, the normal ignition of the TPVS occurs near the candle, while in the surrounding cavity there is a mixture of clean air and exhaust gases supplied to the inlet by the EGR system. As you understand, it is not possible to implement such a method of gas exchange in a conventional engine.

Engine operating modes

GDI motors can work effectively in several modes:

• Ultra-LeanCombustionMode- super-poor mixture mode, the flow principle of which was discussed above. It is used when there is no heavy load on the engine. For example, with smooth acceleration or constant maintenance of not too high speed;
• SuperiorOutputMode- a mode in which fuel is supplied during the intake stroke, which allows obtaining a homogeneous stoichiometric mixture with a ratio close to 14.7/1. Used when the engine is under load.
• Two-stagemixing- rich mixture mode, in which the ratio of air to fuel is close to 12/1. It is used at sharp accelerations, heavy load on the engine. This mode is also called the open loop mode (Open loop), when the lambda probe is not interrogated. In this mode, fuel trim to regulate emissions of harmful substances is not carried out, since the main goal is to get the most out of the engine.

Responsible for switching modes the electronic unit engine control (ECU), which makes a choice based on the readings of sensor equipment (TPDZ, DPKV, DTOZH, lambda probe, etc.)

Two-stage mixing

The dual-stage injection mode is also a feature that allows the GDI engines to be extremely responsive. As mentioned above, the composition of the mixture in this mode reaches 12/1. For a conventional engine with distributor injection, such a fuel-to-air ratio is too rich, and therefore such a TFA will not ignite and burn efficiently, and emissions of harmful substances into the atmosphere will significantly worsen.

Open loop mode involves 2 stages of fuel injection:

• a small portion on the intake stroke. The main purpose is to cool the gases remaining in the cylinder and the walls of the combustion chamber themselves (the composition of the mixture is close to 60/1). Subsequently, this allows more air to enter the cylinders and create favorable conditions for igniting the main portion of gasoline;
• main portion at the end of the compression stroke. Thanks to the favorable conditions created by the pre-injection and the turbulence in the combustion chamber, the resulting mixture burns extremely efficiently.

There is a great desire to talk about exactly how Mitsubishi engineers “tamed” turbulence, about laminar and turbulent motion and the Re number introduced by O. Reynolds. All this would help to better understand exactly how layer-by-layer mixture formation is created in GDI motors, but, unfortunately, two articles are not enough for this.

injection pump

As in diesel engine, a high pressure fuel pump is used to create sufficient pressure in the fuel rail. Over the years of production, the motors were equipped with high-pressure fuel pumps of several generations:

nozzles

To ensure high-precision control of the composition of TPVS, the nozzles must have extremely high accuracy. The very principle of opening the plunger for fuel supply is similar to a conventional electromagnetic nozzle. Features of the GDI system injectors:

• the possibility of forming different types gasoline spray;
• maximum preservation of dosing accuracy regardless of temperature and pressure in the combustion chamber.

Particularly noteworthy is the swirl device located in the nozzle body. It is thanks to him that the fuel, flying out of the nozzle, is better picked up by the swirling air flow, which contributes to better mixing of the TPVS and redirecting the mixture to the spark plug.

Exploitation

The main troubles associated with the operation of direct injection engines from Mitsubishi in domestic open spaces:

• TNDV wear. The pump is an assembly with pretentious requirements for fitting parts, and the main problem is not the level of manufacture, but the quality of domestic fuel. Of course, even now you can run into bad fuel. But the days when the quality of gasoline was a real headache and the risk of financial loss for owners of cars with GDI engines, fortunately, have already passed;

blockage of air passages in the intake manifold. The formation of build-ups corrects the movement of air masses and the process of mixing fuel with air. This is what is called one of the reasons for the formation of black soot on spark plugs, which is so well known to owners of cars with GDI engines.

GDI

PUMP DESIGN

DIESEL injection pump "NOT LUCKY"

BALANCING

WEAR OF INJECTION DRUM

UNSTABLE OPERATION XX

PUMP WEAR

"Sand" in gasoline.

LOW PRESSURE IN THE SYSTEM

PRESSURE SENSOR (error #56)

Pressure sensor

Fuel pressure sensor

PRESSURE VALVE

PRESSURE REGULATOR

PRESSURE CHECK

Private pressure recovery method

DIMENSIONAL CHECK

REDUCER VALVE

REDUCER VALVE hexagon)

CORRECT ASSEMBLY OF THE PUMP

PUSHER-BLOWER

FILTER IN THE PUMP

OSCILLOGRAM OF WORK

A special case of pump repair

FUEL PUMP HIGH PRESSURE ENGINE GDI

At the moment, four types (options) of high-pressure fuel pumps of GDI systems are known:

Let's begin to consider the device of this system. Only without general phrases and concepts, but specifically.

Let's start our acquaintance with the so-called "single-section" high-pressure fuel pump installed on the 4G93 GDI engine, the working pressure in which is created using seven plungers:

"Three-section" injection pump and its device, operation, diagnostics and repair, we will consider in subsequent articles. It is this injection pump that has been installed recently (after 1998) on almost all cars with the GDI system due to the fact that it is more reliable, more durable and, in principle, better amenable to diagnosis and repair.

In short, the principle of operation of this GDI system is quite simple: an “ordinary” fuel pump “takes” fuel from the fuel tank and delivers it through the fuel line to the second pump - a high pressure pump, where the fuel is compressed further, and already at a pressure of about 40 -60 kg/cm2 goes to the injectors, which "inject" the fuel directly into the combustion chamber.

The “weakest link” in this system is this high pressure fuel pump (photo1), located on the left in the direction of travel (photo2):

photo 1 photo 2

Disassembling such a pump is quite simple:

This is an "ordinary" seven-plunger pump:

inside which is the so-called "floating drum":

Below you can see a general view of the pump disassembled for repair:

From left to right:

1. pressure washer

2. snap ring

3. floating drum

4. Plunger support ring

5. Plunger with cage

6. Plunger Thrust Washer

A little higher, we said that the GDI injection pump is the "weak link".

It is not difficult to guess for what reasons, because not only GDI owners, but also "ordinary" motorists began to understand that if some strange interruptions in work began in the car (in the engine), then the first thing you need to pay attention to is spark plug.

If they are "red" - who is to blame? Someone...

Only change, because such spark plugs are not subject to any "repair", as sometimes prescribed on the Internet.

FUEL

Yes, it is precisely this that is the main cause of the "disease" of direct fuel injection systems. As well as GDI and D-4.

In the following articles, we will tell and show with specific examples and photographs - HOW exactly and WHAT exactly our "high-quality and domestic" gasoline affects, for example, on:

photo 7 photo 8

PUMP DESIGN

It's only "the devil is terrible when he is painted", and the GDI injection pump device is quite simple.

If you understand and have some desire, for example ...

Look at the photo and see in disassembled condition high-pressure single-section seven-plunger pumpGDI:

From left to right:

1-magnetic drive: drive shaft and splined shaft with magnetic spacer between them

2-Plunger Support Plate

3-cage with plungers

4-seat plunger cage

5-pressure chamber pressure reducing valve

6-valve adjustable high pressure outlet with injectors-fuel pressure regulator

7-spring damper

8-drum with plunger pressure chambers

9-washer-separator of low and high pressure chambers with refrigerators for gasoline lubrication

10-case injection pump with solenoid valve reset and with a port for a pressure gauge

The order of assembly and disassembly of the injection pump is shown in the photo in numbers. We exclude only positions 5 and 6, because the valve data can be set immediately during assembly, before installing a drum with plungers (these valves and some of their features will be discussed in another article dedicated specifically to them).

After assembling the pump, you should fix it and start turning the shaft to make sure that everything is assembled correctly and rotates without "wedges".

This is the so-called simple "mechanical" check.

In order to conduct a "hydraulic" test, you should check the performance of the injection pump "for pressure" ... (which will be discussed in an additional article).

Yes, the injection pump device is "quite simple", however ...

Many complaints from GDI owners, many!

And the reason, as has been said many times "on the Internet" is only one - our native Russian fuel ...

From which not only the spark plugs "turn red" and with a decrease in temperature the car starts up disgustingly (if it starts up at all), but the "swallow" with GDI is wasting away and wasting away with every liter of Russian fuel poured into it ...

Let's look at the photo and "point the finger" at everything that wears out in the first place and what you need to pay attention to first of all:

Cage with plungers and drum with injection chambers

photo 1(complete)

if you look closely (take a closer look), you will immediately notice some "incomprehensible scuffs" on the drum body. What then happens inside?

photo 2(apart)

photo 3(drum with pressure chambers)

and here you can already clearly see - WHAT our Russian gasoline is ... the same reddishness, just rust on the plane of the drum. Naturally, she (rust), not only remains here, but also gets on the plunger itself and on everything "on which it rubs", - look at the photo below ...

Plunger

photo 4

and in this picture it is clearly visible, what "little troubles" our - native - gasoline can bring us.

The arrows show "some abrasions", due to which the plunger (plungers) stop building up pressure and the engine starts to "work somehow wrong ...", as the owners of the GDI say.

To restore the GDI injection pump, it would be nice to have "some" spare parts:

photo 5

Other "weak" points of the GDI high pressure fuel pump will be discussed in other articles.

And also about many other things.

DIESEL injection pump "NOT LUCKY"

High pressure diesel fuel pump "out of luck"...

Because it has only one plunger, and when it fails ("sits down", there is such a thing), then problems of a different nature begin.

The GDI high pressure fuel pump, which has such a name as "seven-plunger", is, presumably, devoid of such problems?

This is how to look and from which side.

A Mitsubishi car with a GDI 4G93 engine did not come for diagnostics, it "came". Barely, slowly, slowly, because the engine worked somehow.

But the most interesting thing is the prehistory of the repair route - where this car returned from.

Oddly enough, before this car was diagnosed in a dealership of this brand of cars.

And what's there?

Oddly enough, but according to the Client: "they couldn't do anything there."

Oddly enough, but they could not do the simplest and most banal - check the "high" pressure.

Okay, let's leave these arguments "overboard" of our story, although they lead to rather sad thoughts expressed by a "Moscow provincial" in a recent article on the "open spaces" of this Internet site, thoughts that confirm and convince: "Oh, there were people in our time!..".

Well, okay, what happened to this car and why he did not come, but "came on foot" to, as the Client said, "the workshop of my last hope."

"Idle instability".

With all that it implies.

When we checked the "high" pressure, it turned out that it was the minimum allowable for "more or less" stable operation of the engine, only 2.5 - 3.0 MPa.

Naturally, what kind of normal and correct work can we talk about in this case?

Let's pause.

And now look at photo 1: we deliberately stopped the workflow of checking the pressure in this very place, when the pressure gauge is not completely connected and rests on only one mount.

So - do - you can not!

And you, of course, understand why: the fuel (gasoline) pressure during engine operation is tens of kilograms per centimeter and, if God forbid, the fitting does not withstand and breaks, then ...

As usual, as it should be in this workshop: removed and disassembled the high pressure fuel pump. They looked and "looked closely" with the help of an instrumental check on the condition of the plungers and found that they were practically "dead".

Like the plunger, so is the "drum".

But the most interesting is yet to come...

The fact is that lately there have been too many repairs of these particular injection pumps with the replacement of individual parts, and it just so happened that for this injection pump it turned out to be almost impossible to find normal plungers suitable for the technical conditions ...

It's okay, because from any hopeless situation - there is a way out.

Only for this you need to have "a little" more gray matter and, most importantly, experience that comes with age.

The output was found as follows:

Picking the "right drum" is the first thing.

Second: pick up a few plungers that would "not let through" and a few - that would "crush".

Based on this, the "GDI-Solomon solution" was found -

4 plungers with dimensions 5.956

2 plungers with dimensions 5.975

1 plunger size 5.990

photo 2 photo 3

Also, look closely at photos 2 and 3.

If in photo 2 you can notice the differences between the plungers, then in photo 3 - what?

"A drum is like a drum," as they say.

Let's pause and find out. And let's lift the veil of the "mystery" of the mechanism for selecting and selecting plungers and a drum a little, because the main question here is: how to choose, by what parameters, what to look at, how to look.

Photo 2. It can be seen that the plunger data have differences in appearance. But not only in appearance, but also in its chemical composition, due to which the one at number 2 - low wear.

Photo 3. As they say: "A drum is like a drum"? Colour. It's closer to brown. And this also suggests that such a "drum" is also low wear.

Conclusion: it is necessary to select and install from such. Which is what was done.

The result of the work done can be seen here:

So the diesel pump is really "unlucky": it "dies" immediately if its plunger is out of order. but the "seven-plunger" GDI high-pressure pump can still "fight"!

FUEL PRESSURE RELIEF SYSTEM

Yes, let's talk again about pressure in the direct fuel injection system, on its maintenance and emergency reset in case of unforeseen situations ...

photo photo 2

In the above photos you see the emergency pressure relief valve, which is on the injection pump fourth generation stop installing.

From photo 3 it becomes clear that the device of this valve is quite simple, it consists of only two parts: a calibrated spring and a stem of a special configuration (photo 3).

The stem is inserted into the hole of the stacked plate valve (photo 1), and with the other side into the pusher-supercharger, where it rests against the piston (photo 2).

The principle of operation is just as simple: as soon as the pressure inside the high-pressure fuel pump in the high-pressure channels exceeds the reading of 90 kg.cm2, the valve rises under the influence of this increased pressure (remember, a calibrated spring) and then two actions occur simultaneously:

1. overpressure will "smoothly" flow into the low pressure chamber

2. the valve spring will be compressed and under its influence another spring will be “pinched”, which is located in the pusher-supercharger, and thus, while the pressure is decreasing, the piston of the pusher-supercharger will reduce its performance

As soon as the pressure drops to a value of 50 kg.cm2, the valve closes and everything starts working as usual.

This valve is no longer installed on newer GDI models. It is difficult to say for what reasons, but most likely due to the fact that the "reinsurance Japanese soul" originally installed this valve, because such a phenomenon as an increase in pressure to 90 kilograms almost never occurs.

The other valve is "operating at low pressure"

photo 4 photo 5 photo 6

photo 7 photo 8

It is installed at the "outlet" of low pressure to the "return" (photo 7).

The appearance of the valve and its dimensions are shown in photo 4-5-6, and photo 8 shows an already disassembled valve (in principle, it is non-separable, but if you try ...).

This valve is intended for one thing: "do not dump fuel into the return line below the set value."

The manual says that this "set value" is equal to 1 Mpa, but Practice refutes this frozen opinion (erroneous translation? unwillingness to understand because the NAME already works on repaired cars?) and claims that this valve works at a value of 0.1 Mpa.

All mentioned valves do not require any special cleaning and adjustment, because all this (calibration) is done forever even during assembly.

Of course, "a particularly burning technical soul" in the presence of Desire and Time can always try to change something and then see what happens.

One advice: before starting such work, carefully study Pascal's law ...

BALANCING

Such an expression as "balancing the injection pump" has not yet been mentioned in our articles, but now it's time to talk about it - what it is, why and how it is done by Dmitry Yuryevich, a specialist before diagnosing and repairing direct fuel injection systems, in an ANKAR car service.

When the Client expresses such descriptions of a malfunction as: “It pulls badly, there is no power” and the like, then the first thing to pay attention to is the ignition system and the high pressure fuel pump:

photo 1 photo 2

photo 3 photo 4

It doesn’t make much sense to work on diagnosing direct fuel injection systems with “simple” equipment, because “proprietary” devices not only facilitate diagnostics, but also allow you to do it more efficiently and quickly.

The above photographs just speak of this, well, tell me, how else can you more accurately understand the ongoing processes in the ignition system, if not with the help of the device shown in photo 2?

Or, photo 4 shows the display of the MUT2 dealer scanner, which allows you to "collect together" the necessary parameters and at the same time watch to make the most correct decision to determine the existing malfunction?

Expression " no pressure"- is a real "sentence" of the high-pressure fuel pump, but in order to be completely convinced of this, it is necessary to carry out additional checks so that later the "sentence" is not subject to appeal.

The most accurate check is "instrumental", when the high-pressure fuel pump, based on the readings of the scanner and additional checks, is disassembled, inspected and measured.

The reason for the "sentence" of the described high-pressure fuel pump was this:

photo 5 photo 6

Photos 5 and 6 - plunger cage washers.

In photos 5 and 6, the arrows show the surfaces that are subject to wear. For a better view, click on the following photo:

It is clearly seen that on the puck number 1, the wear is very noticeable. On puck number 2, the output is, one might say, "standard".

So, what can all this talk about?

Based on his experience, Dmitry Yuryevich can assume that such worn surfaces are obtained due to imbalances plunger cage drum.

Although, if you look at it "just like that", then what can you see?

Almost nothing. But in order to really "see", one must have many years of experience, because only after it comes the second and complete definition: "See and Understand".

If you have even a little experience with the disassembly-assembly of engines, you should know that there is also such a thing as "balancing", where the piston is selected by weight.

So it is here (in principle, and with some "stretch"), but only the selection is not for pistons, but for plungers (photo 8).

Their selection takes place according to such a principle, which can be called "equilibrium" (photo 8):

For example, plungers numbered 1-2 should match plungers numbered 4-5. Etc.

It is impossible to put a plunger next to each other, for example, with the same dimensions 5.970.

The conclusion is this: plunger wear also occurs for such a reason as "drum imbalance".

That is why, before "sentencing" the injection pump, it is necessary to carry out many checks and measurements that are difficult to carry out right without the necessary equipment.

WEAR OF INJECTION DRUM

Many malfunctions of GDI engines arise, as already mentioned, due to low-quality fuel: frankly "dirty", or with "super" additives, or simply "inappropriate". Or the so-called "human factor".

The photos below show just such a malfunction, which just arose for these two reasons: the “factor” and the fuel.

Photo 1 shows two "drums" and, if you look closely, you can see that the one on the left is the one that seems to be "smoother" and "more pleasant to look at" than the one on the right.

Following the arrows in photo 1, we will see that the plane of the left "drum" is different, and quite strongly from the plane of the right "drum".

Photo 2 shows the same "reciprocal" parts directly adjacent to the "drum". The arrows in photo 2 (left position) show “scuffs” and scratches that arose due to the already mentioned “factors”.

Such a fuel pump will practically not work anymore. Because there will be no pressure, or it will be “on the verge of a foul”, as they say. “Metal does not speak”, it can only “tell” us what and how it happened. Let's try to consider the "case history" of such a malfunction?

Photo 3 shows a nearly life-size "erased drum" (constantly compare it with the same, but "smooth and fair" in photo 1 (left).

So, let's take a look:

Position "a" - this should be the entire surface

Position "b" - the first "stage of production"

Position "c" - the second "stage of production"

The arrows under No. 1 show the "width of the working" "c" - the largest and deepest.

As we know, in a high-pressure fuel pump, all its parts that come into contact with gasoline are “lubricated” with it. And they cool down.

photo 3 photo 4

Quality and more quality. Only this will “save” the planes (surfaces) processed with the highest accuracy from damage and, as a result, “save” the required pressure at the “exit” of the injection pump.

"Sand", one and very small, which may be in fuel tank and which, due to its small size, will be able to “crawl” through the meshes and cleaning elements of the fuel filtration and get into the “holy of holies” of the fuel pump (photo 4, position 1, the remaining “traces” from the “grain of sand”), first began to “work out” the position “ b" (photo 3).

When the driver “drowned the gas to the floor”, the “grain of sand” moved closer to the center and began to actively “work out” the circle “c” (photo 3), resulting in such a Deep working (arrows 1, photo 3).

It’s a little unclear what the expression and consequences of this, like “gas to the polik” have to do with it?

With what's going on here:

1. increase in revolutions (naturally) and the speed of rotation of the "drum".

2. the “friction rate” increases, which requires increased fuel cooling, which may not be enough due to low performance of the booster fuel pump in the fuel tank, “clogging” fuel filter in front of the injection pump, "clogging" of the fuel "filter" in the injection pump itself, which will lead to a decrease in the required amount of fuel not only for the "production" of pressure, but also for cooling and "lubrication" rubbing parts of the high pressure fuel pump.

So the "active development" of planes begins.

Of course, all this is a bit approximate and relative, because no one has yet "looked" inside the fuel pump during its wear and we can only speculate ...

UNSTABLE OPERATION XX

Quite often, the engine starts to run unstable at idle and, in principle, only with the help of a scanner that "understands" GDI, you can determine the "area" of the malfunction: "low pressure".

Without knowing the features of this fuel injection system or not having enough practice, you can look for a malfunction for quite a long time, going through or trying to fix exactly what seems most likely for this malfunction.

We will try to help in this matter and tell you about the most common malfunction, due to which the "unstable XX" occurs. Let's look at the photo:

photo 1 photo 2

photo 3 photo 4

In photo 1 you see a "seat", and in photo 2-3-4 you see the "lamellar valve" itself, which is the "first stage" of pumping fuel to create high pressure.

The plates are arranged exactly as they are to be assembled.

At first glance, even these plates shown in the photo are in perfect order.

However, if you look closely (it's good, of course, to have an ordinary magnifying glass on your desktop), you can notice "something":

photo 6 photo 7

This "something" is especially noticeable in photo 5.

Here are two identical plates. But if you look closely, you can visually determine that on the left plate (number 1) the light rim around the hole is much smaller than on the right plate (number 2).

It was found that " appearance"of such a production will be approximately like this:

As we can see, the "shelf" of working "a" is much smaller than the "shelf" of working "b".

This is how wear occurs around these bypass holes. As well as due to quite natural wear and tear, and due to low-quality (dirty) fuel.

And then the middle plate of the inlaid reed valve will “incorrectly” adjoin the hole, approximately as we tried to model in photo 6.

And on the basis of Pascal's law, and also taking into account that the liquid (gasoline) is subjected to heat, vibration, that it may not be completely homogeneous, and so on, it turns out that such a development at different holes may not be "centered" , and shifted both to the left and to the right.

And now you can write or remember:

If one hole "does not hold" ... no, here it is necessary to stop and make a reservation, because recently there have been too many "criticizing elements" that may well find fault with this expression: "... does not hold ... hole ... ", - and the" bodyaga "will be divorced according to" exact "expressions", according to "incorrect" expressions, the Internet will again be clogged with statements about "fundamental disagreement with the author" ... and so on and so forth ... although, if you do not try to pull the expression out of the whole context, then everything is quite clear, isn't it?

So, " if not holding one hole"(photo 7), then the engine will work on the twentieth, but its revolutions will be -" walk ".

If " does not hold "already two holes, then the XX revolutions will always "walk".

If " does not hold" three holes, then XX simply will not.

Well, there is no need to talk about the fourth. This will most likely not come to that.

Particular care must be taken when attempting to restore the middle spring plate.

You yourself understand that it is only necessary to bend it "embarrassingly", bend it and ... naturally, there will be no pressure.

All plates can be restored. Just don’t “rub” them all the way, it will be enough to “remove” black or rusty deposits with the help of lapping paste for valves and subsequently restore an even “landing” plane for the springy petals of the middle plate with the help of “skin-2000”.

PUMP WEAR

As our grandmothers used to say, remember?

"You don't have to save on your health ...", - and if we slightly alter this expression in relation to a car, then we can say this way:

"Don't skimp on fuel."

Among motorists there is a very, very common opinion that "ninety-second is much better than ninety-fifth." And numerous examples are given that, they say, on the ninety-second it starts up better, and the consumption is less, and so on, and so on ...

This question is very, very controversial. You can say a lot and for a long time.

But we'll just give an example of how "GDI relates to ninety-two".

A client on a Mitsubishi "Legnum" of 1996 with a 4G93 engine (right-hand drive) came with such complaints about his car: "Something began to accelerate badly ... uncertainly idling ...".

The car was purchased only half a year ago and at first there were no complaints about it. And then it all started ... but somehow imperceptibly, "smoothly", if I may say so.

The first step was to check the pressure of the high pressure fuel pump.

It turned out that at XX it "presses" only about 2.0 Mpa (about 20 kg/cm2).

The captured Data Stream confirmed the initial mechanical test: "low pressure developed by the pump".

At rpm - yes, the high-pressure fuel pump "pressed" about 5.0Mpa, but at the twentieth, alas.

What happened when disassembling the fuel pump and what causes of the malfunction were found:

photo 1 photo 2

Photo 1 and photo 2 show an adjustable pressure relief valve. In photo 2, the arrow indicates the place of maximum wear of the precision part.

photo 3 photo 4

Photo 3 and photo 4 show the "drum" and the washer - "shaper-distribute pressure".

In photo 3, arrow 1 shows the place of contact, where the wear of parts occurs.

Only one side wears out (photo 4, position 2) - on the "drum".

On this "drum" the change in size was about 0.7 mm.

photo 5 photo 6

Photo 5 shows the location of the "filter", and photo 6 shows the "filter" itself, only it stands "on the contrary", when installed it turns over.

So, the "filter" was heavily clogged ...

photo 7 photo 8

By clicking on photo 7 we will see an enlarged image of the plungers. And we will determine, only visually, that they are very "worn out".

And to be specific, let's look at photo 8.

Arrows "a" and "b" show the stroke distance of the plunger, which is about 6 millimeters. At point "a" the diameter was 5.975 mm, and at point "b" 5.970 mm (remember the "ideal" dimensions: 5.995 mm).

All these pictures are just to show "the effect of 92 Gasoline on the GDI High Pressure Fuel Pump".

Yes, it was this gasoline that so affected the high-pressure fuel pump in just half a year of operation.

If you refuel "ninety-second" all the time, then the resource of the high-pressure fuel pump will be from a year to a year and a half (approximately, because there are quite exceptional examples when GDI "went" at "ninety-second" and for a much longer time).

So, why did this particular gasoline under that name become a "talk in the tongues" in our article?

"Sand" in gasoline.

This is exactly what you can say and call these words the cause of the above malfunction. The word "sand" is very conditional, because it means "foreign impurities" to the fuel: mechanical impurities, water, corrosion products and everything that remains in the tanks on the walls - oil, fuel oil, diesel fuel and so on and so on.

All this is safely mixed during transportation, then merges into underground containers at gas stations and is also safely sold.

You can ask a completely fair question: "ninety-fifth - better?".

Yes, better.

Only to say "how much better" is difficult, because every opinion is subjective.

What conclusion can be drawn from all this?

Only one: refuel with non-92 gasoline, purchase a more expensive one, because only under this condition can you both extend and "maintain the health" of your car.

LOW PRESSURE IN THE SYSTEM

The name of the car was unusual: "ASPIRE", however, in Japan there are many unusual things. not just car names. Engine 4G93 GDI.

How did you work?

Yes, nothing, in principle, if I may say so, getting used to the fact that many GDIs work, unlike "regular" gasoline engines, a little differently.

Sometimes "hard", as if all the hydraulic compensators "lay down", sometimes softly and quietly - "like a cat".

This one worked - "average", so to speak.

Nothing unusual. Like the majority. Checking the scanner showed. that "inside" everything is in perfect order, there are no fault codes, only ...

Yes, of course, they paid the very first and closest attention to the pressure, looked at what the scanner shows, and then double-checked everything with the "mechanics" and ... spread their hands in front of the Client: "We'll have to look at the pump and sort it out."

The pressure was about 4Mpa, and therefore there was a feeling that the engine, although it was working, was still "somehow wrong."

Everything is right because Diagnostics is not only instrument readings, it is also the sensations of the Diagnostician himself that he "sees, hears and feels".

And when disassembling the injection pump, this is what turned out:

photo 1 photo 2

Of course, this is only a small fraction of what could be photographed and shown. And it is taken as an example to once again "assume" that a thoughtless passion for various kinds of additives that are "super" and so on, all this has never led to anything good. Especially - in GDI.

You know how often it happens: being tempted by multi-colored labels and inscriptions under them (Instantly removes water! Eternal life to your motor!), And then succumbing to the reasoning of the seller, who needs only one thing - to sell, and then "grass does not grow", a person buys and ... fills.

On this engine, the Client also filled in "some" additives. What exactly - he himself, probably, finds it difficult to remember.

Okay, all this can be eliminated, including:

GDI owners can’t get away from this, that’s why it’s necessary regularly carry out maintenance.

In addition, they "removed" the black carbon deposits in the tubules of the high-pressure fuel pump, cleaned it, or rather, "brought it" on the stove to the valve's working state. All together it took about two hours.

They put everything back together, started the engine and ... Well, here it is again "and".

Yes, the engine was running, but again "somehow wrong."

The instruments were all right, but the sensations were not.

There is such a thing as "give gas."

So, with "sharp gas" the engine developed speed "cleanly" (conditionally), but with "sharp moderate gas" the engine "spent".

Then already again paid attention to the ignition system.

In photo 5 you see two spark plugs with different soot colors.

There was only one “light” spark plug, but all the others were “as expected” - dark in color.

After replacing the nozzle on the cylinder where the candle was "light" - everything, even the "feelings" smiled with satisfaction: "The car can be given away."

And what does the city of Perm have to do with the title of the article, you ask?

Only despite the fact that this car was driven from there to Moscow only in order to carry out maintenance.

No comments?

PRESSURE SENSOR (error #56)

This is the tastiest DTC for Thinking Diagnostics, because it gives free rein to both the hands and the mind.

There is no specifics in this fault code ("Abnormal pressure ..."), everything is only in general, which is especially valuable and attractive (naturally) for most of the Diagnostics.

So, let's first see what "the manual tells us", on which we will rely.

But - only rely on and no more.

Don't be guided.

This DTC is completely pressure related. Or its definition "through" the pressure sensor, or its "specific loss", which also determines the pressure sensor.