Modern cars drives It is characterized by a certain scheme of work. Inside the chamber of this system burns fuel-air mixture. This means that when refueling a car with gasoline or diesel, the driver provides only one necessary element for the movement of the vehicle.

The fuel is mixed with air. gasoline or diesel. The fuel evaporates in front of the valves. In the cylinders, the mixture of fuel and air is burned by an electric spark. If issued, this means that the system has detected a deviation. It's a rich mixture. But you can independently see the engine malfunctions caused by such a problem. How to fix it, every car owner should know.

General concept

Understanding what is too rich mixture (VAZ, Skoda, BMW, Chevrolet, etc.), a few words should be said about the fuel itself. It consists of gasoline (diesel) and air correlated in a certain proportion. Liquid fuel is supplied to the engine cylinders. This ratio largely depends on its quantity.

A rich mixture is one that contains more gasoline and less air. Since there is not enough oxygen inside the combustion chamber, the process of engine operation loses power. Afterburning of gasoline occurs because of this already in the muffler. Some auto mechanics call this state of the fuel high-calorie.

These violations are reflected on the outside. A characteristic black soot, soot appears on them. There may be several reasons for this state of the engine system. They must be found and eliminated.

When the mixture gets rich

Deviations in the preparation of the mixture appear as a result of certain failures of the vehicle's systems. The injector is responsible for the process of creating fuel. It prepares mixtures with a certain percentage of oxygen. It is this ability of the presented engine element that allows the engine to operate in different modes.

If necessary, the driver can, thanks to such a device, increase speed, cope with the rise, overtake, etc.

It is determined by a mathematical formula. The ratio of 14.7 kg of oxygen per 1 kg of liquid fuel is considered normal. If in this formula, for some reason, the amount of oxygen increases, such a composition is called poor. If the amount of fuel in the mixture rises, the mixture acquires the status of rich.

The owner of the car can independently adjust the level of oxygen supply to the fuel mixture. Mistakes made in this process lead to breakdowns and improper operation of the vehicle.

Signs of deviation

Rich mixture - VAZ, UAZ, BMW, Audi and other existing car brands - can be manifested by a wide range of deviations in the operation of the car. If such violations occur, it is urgent to find out the cause of this condition of the engine.

In vehicles in which an autoscanner is installed, when the deviations presented occur, an indicator lights up with the corresponding error code (P0172). The muffler in this case may emit loud pops. This is due to the combustion of air in the exhaust pipe. This is one of the first signs of violations.

At the same time, one can notice the appearance in exhaust gases black, grey. This is also due to the inappropriate way the fuel burns out. Exhaust is not cleaned. The pipe contains a lot atmospheric oxygen. Therefore, the exhaust gas acquires a characteristic dirty tint.

Driving a car

Too rich mixture also manifests itself when driving a vehicle. Almost any driver will immediately notice this. The car becomes less dynamic. Engine power drops sharply. Since the combustion process in the motor chamber is slower, the mechanism is not able to work at full strength.

In some cases, the car may not even go. But this is with very serious deviations in the ratio of fuel and air in the combustion chamber.

When driving a car, the owner may notice that fuel consumption has increased. it's the same feature engine malfunctions due to operation with a rich mixture. This violation is explained simply. The engine in such conditions does not work efficiently. The fuel mixture is consumed incorrectly. To prevent low speed combustion, the engine begins to inject more liquid fuel into the chamber.

Main reasons

There are several main reasons that cause deviations in the ratio of air and gasoline. The most basic of them can be deviations in the engine control system, as well as malfunctions of the air damper drive. An injector malfunction can also explain why rich mixture. Carburetor if set incorrectly, it can also cause deviations. Another factor in the formation of a rich mixture is clogging. air filter.

Often the cause of violations in the fuel system is the wrong actions of the car owner. In order to reduce gas mileage or increase engine power, the driver may not properly adjust the system. As a result, he gets problems with the engine and the need for extraordinary maintenance or even repairs.

Fuel deviations

Since the process of forming a combustible mixture consists of two main components (gasoline and air), violations are possible from the supply side of each of them. Excess fuel is determined much less frequently than lack of air. But typical fuel supply violations should be considered in more detail.

Too rich a mixture, the causes of which are related to the fuel system, can be caused by high pressure in the line. This deviation is caused by a malfunction of the fuel pump or regulation system. To check this version, use a special fuel gauge.

Deviations in the composition of the mixture can be caused by the adsorber. Due to a malfunction of the vapor recovery system, a large amount of gasoline is admitted through it.

Also may be faulty when closed may be unable to hold fuel. This causes it to enter the chamber even when the nozzles are closed.

Air supply problems

"Rich mixture" error, which is determined by the vehicle diagnostic system, is much more often caused by insufficient oxygen supply to the combustion chamber. There are several reasons for this violation.

First of all, the air filter may be elementarily dirty. For some reasons ( difficult conditions operation, driving on dirty roads), this element of the oxygen purification system may become unusable even earlier than the period specified by the manufacturer. Therefore, it is necessary to visually evaluate the cleaner. If it is dirty, covered with oil, it must be replaced urgently. Otherwise, the motor will quickly fail.

In some cases, the cause of inadequate air supply to the combustion chamber may be a breakdown of its flow sensor. This will help to identify the system readings of the scanner. Sometimes a malfunction of the air pressure sensor in the manifold system is determined.

Automatic diagnostic system

If the vehicle diagnostic system indicates that a "Mixture too rich" error certain actions need to be taken. To do this, you need to understand the principles of the scanner.

Air is supplied to the fuel when diagnosing the MAP sensor and the lambda probe. Maybe it is caused by deviations of these particular systems. However, in addition to them, problems may be associated with deviations in thermal gaps (engine with LPG), with mechanical damage sealing materials, insufficient compression or deviation during timing operation.

To understand why automatic diagnostics indicates such an error, the vehicle owner can take several actions. First of all, you need to analyze the information that the scanner provides. Next, you can artificially simulate the conditions for the appearance of such a malfunction.

The next step may be to check the components and mechanisms, such as contacts, the absence of suction, as well as the operability of systems associated with the supply of fuel and oxygen to the combustion chamber.

Troubleshooting a system error

If the diagnostic system indicates that the vehicle is using a rich mixture, a number of actions must be taken. A faulty node is found during a sequential check of each system. To do this, the JOT, MAF sensors, as well as the lambda probe, are checked with a multimeter.

If no deviations are found in these systems, it is necessary to pay attention to candles, coils and wires. Next, the fuel pressure is measured using a pressure gauge, and the ignition marks are also checked.

Then check the seals and connections at the air inlet, as well as exhaust manifold. There shouldn't be any suction. After carrying out all the manipulations and eliminating the malfunction, the fuel supply adjustments are reset. In this case, long-term programs with respect to this setting return to their original value.

If the fuel tank is preparing mixture too rich, the first thing experienced auto mechanics recommend doing is resetting the advanced settings for the injector. If the owner made self settings fuel control system, he could make serious mistakes. A rich fuel mixture will lead to inevitable engine failure very soon.

If the cause of deviations is related to the nozzle system, this can be determined visually. With such a malfunction, traces of fuel combustion appear on the outside of the injector.

Burning and soot can also be found on one side of the sealing copper ring. Such deviations are caused incorrect installation injector. If a sealing ring is not in its place, similar malfunctions are also possible.

Rare breakdowns

Experts say that 90% of all errors are related to injector adjustment. Eliminating it is easy. The main thing is to pay attention in time to the incorrect operation of the car engine.

The most rare, exotic are considered to be malfunctions of the engine control unit, as well as bad condition contacts. Sometimes there are cases of oxygen sensor poisoning. An experienced specialist is able to identify such deviations. In this case, not every car owner can solve the problem on their own.

Having considered what a rich mixture is, one can understand the danger of such a situation. In the event of an emergency, it is best to contact service center. Service stations have essential tool which can be used to diagnose. This will save the car's engine.

A power supply system (in other words, fuel) is provided. There is an opinion that diesel cars are more picky about fuel quality. It really is. Yes, and the repair of such a system is many times more expensive. Today we will consider what the diesel engine fuel system is, its device and the main malfunctions.

Device

Conditionally this system can be divided into two circuits: high and low pressure. The latter prepares the fuel and sends it to the "next level", to the second circuit. The high pressure system performs the function of the final injection of fuel into the combustion chamber of the engine.

The low pressure circuit chain includes a number of structural components. These are a filter, a separator, a fuel drive, a heater, and also a pump. Fuel passes through each of the above parts. The pump creates pressure in the system, the heater in cold weather heats the "diesel fuel" to the desired temperature (since in winter it turns into paraffin slurry), and through the filter the fuel enters the second, no less important circuit in the system. It consists of the following parts:

• It connects with the filter.
• Nozzles. Recently, injectors with direct injection fuel. It is believed that they are designed for a more accurate dosage of fuel. The machine does not lose power, while the consumption drops.
• Fuel lines - lines through which the mixture enters the cylinders.

Below we will consider the main malfunctions of the diesel engine fuel system.

Difficult start

This happens especially often in cold weather. It is believed that it is almost impossible to start a diesel engine without preheating in winter. In order to somehow alleviate this situation, manufacturers have provided arctic fuel, which includes antifreeze additives. But a difficult start does not always indicate frozen fuel. If the car does not start well even “hot”, most likely the high-pressure pump, namely its injection elements, has failed. It is also worth checking the advance angle of the fuel supply to the engine. It is possible that the nozzles are worn out, due to which the mixture is poorly sprayed in the cylinder. In general, there are a lot of reasons for the difficult start of a diesel engine. Therefore, every detail is checked. Faulty may be incorrect operation of the pressure regulator, lack of fuel in front of the injection pump. Such malfunctions of the diesel engine fuel system (Volkswagen T4 is no exception) are accompanied by depressurization of the fuel lines, due to which air enters the pump, which is no longer able to generate the required pressure.

Power drop

Occurs due to wear or damage to the nozzles. Also, such malfunctions of the diesel engine fuel system occur due to insufficient fuel that enters the pump. Since a filter is installed in front of it, it is likely that it is simply clogged.

Big expense

These malfunctions of the power supply systems of diesel engines occur due to an incorrectly set injection advance angle. Also increased consumption fuel is the result of a malfunctioning fuel pump. Mixture injection pressure level too high. In addition, consumption increases due to low compression in the cylinders.

Black smoke from the exhaust

And if on KamAZ trucks this is considered to be a “factory disease”, which the owners simply do not pay attention to, then on foreign cars the smoke from the chimney is a reason to think seriously. These signs of a diesel engine malfunction indicate poor cylinder carburetion, which may be due to late fuel injection. You should also check the injectors and valve clearances. The “blackness” itself is formed due to soot and loose closure of the intake / exhaust valves of the engine.

White and gray smoke

The head gasket may have been blown in the engine. If this smoke disappears over time, the motor is simply overcooled. This is normal for northern latitudes.

hard work

A diesel engine is inherently noisier than a gasoline engine. However, if the vibrations have increased, most likely, early fuel injection has occurred. Determining the malfunction of a diesel engine is carried out by diagnosing injectors. The compression level in the cylinders is also checked. Its minimum level should be 23 kilograms per cubic centimeter. The range of indicators between the cylinders does not exceed 5-10 percent. The average diesel engine produces about 27-30 "kilograms". To determine, a special tool is used - a compression gauge.

Gaps in acceleration

Symptoms - too short stroke of the gas pedal. In this case, the accelerator linkage should be adjusted. Also check the air filter. It is possible that the high pressure is faulty, because of which it cannot generate the desired pressure in the system.

Swimming "idle"

In this case, check the sealing washers under the nozzles. Look at the fastening of the fuel wire between the filter and the pump. Tighten more if necessary. Also, with similar symptoms of a malfunction in the diesel engine fuel system, look at the pump base plate for damage. The crankshaft may be worn. "Idlers" swim from behind overpressure gases in the crankcase - check ventilation.

Engine stalled

If it stalls on the move, check the offset of the injection advance angle. This is a violation of the connection between the drive and the pump. It is also a dirty filter, which causes a lack of fuel and low supply pressure. As for the pump itself, it is possible to misalign the separator pistons or the rotor. It is worth noting that the injection pump is the most expensive part in the power system of a diesel car. Due to the complex design, the element is difficult to repair, so the cost of restoration is comparable to the price of a new element purchased at a disassembly.

Prevention

To exclude malfunctions of the diesel engine fuel system (because a diesel failure is expensive and long), do not be lazy to carry out preventive maintenance. First of all, you need to flush the system at intervals of 1-2 times a year. This operation includes dismantling the fuel tank and removing the accumulated "sludge" in the fuel filter. Practice shows that a lot of sediment forms at the bottom during operation, which, when driving on an empty tank, instantly clogs up in filters and lines.

Fuel type

This is especially true for the use of the car in the so-called transitional season. The air temperature has already dropped, and gas stations are selling the rest of the summer fuel. It loses its fluidity already at -5 degrees. Then it turns into paraffin, which clogs in the pump and filters. Be sure to specify at gas stations what type of fuel will be poured - summer or winter. If it so happened that the temperature has dropped sharply, and there is summer diesel fuel in the tank, warm the car as much as possible using preheater, or if it's a passenger car - connect a household heater to the garage. When starting a diesel engine, every degree matters.

Do not dilute fuel

Some craftsmen, if necessary, start a diesel engine in the winter, “bodyate” fuel with gasoline. This is absolutely impossible to do. In Russia, special arctic diesel additives have long been sold to prevent the formation of paraffin in the tank. In fact, these same additives are added to the usual summer fuel at gas stations - so it becomes suitable for operation in the winter. There is nothing illegal in this. But diluting it with gasoline is just suicide (meaning for the fuel system).

Warming up in winter

Warm up or not? The fuel system of a diesel engine, the device of which differs significantly from that of a gasoline engine, also needs to be this action. After starting the engine, let it idle for 3-5 minutes, after which drive the first 200 meters in a “sparing” mode for the car. A diesel engine, unlike a gasoline engine, is colder - it warms up much longer. Long work on the Idling is also not required, but you should not ignore the above recommendation.

gas station

Everyone scolds our gas stations for the poor quality of fuel, they say, there is no normal diesel fuel at Russian gas stations. This is fundamentally wrong. One simple rule: fill your car with expensive fuel at well-known gas stations. Everyone wants to save money by buying fuel 10-15 percent cheaper market value literally queuing up. However, after a couple of weeks, having got to repair the fuel station, they begin to blame not themselves, but gas stations. In fact, this is so, but no one forces them there by force. You always have a choice. Remember the main thing - a miser pays twice.

How to increase the resource of high pressure fuel pump?

As we said earlier, this is one of the most critical parts of the fuel system.

In order for the high pressure pump to last longer and malfunctions of the diesel engine fuel system bypass you, you need to:

• Do not leave the tank "half empty" overnight. This is how condensate forms on his machines, which then penetrates into the nozzles and the pump.
• Periodically drain the sludge through the drain plug.
• Do not drive on an empty tank and a constantly burning light bulb.

Conclusion

So, we found out the main malfunctions of the diesel engine. By following these simple rules, you will significantly extend the life of the system and reduce the risk of "getting repaired".

So, let's start listing the reasons.
1) Malfunction or deterioration of the fuel supply system. Both petrol and diesel engines, this item is always checked first if the engine does not pull and is gaining momentum poorly.
At gasoline engines often the fuel pump fails, so the first thing to do is check it, and here it doesn’t matter whether it is electric or mechanical, there are enough examples from life. Even here one, recently familiar with the trade wind with single injection, came, complained about the lack of traction, and where do you think the dog was buried? That's right, the fuel pump was slowly dying, as a result, there was not enough fuel, and the hungry engine was no longer so peppy. Also look at the fuel supply and distribution body itself, carburetor, single injection or injector, but this is already on the site for the fuel workers and not for me. Let them check, adjust, repair.
As for diesels, in most cases, when equipment with injectors dies, the problems described in the title appear. The death of injector nozzles and the death of high-pressure fuel pump plunger pairs lead to a large loss of engine power, to the point that it will completely stop starting.
If you are sure that the equipment with injectors is alive, but the engine stubbornly does not want to gain momentum as expected, you probably have a late ignition, that is, you need to conjure with the ignition timing, do it earlier.
Air leakage in the diesel fuel system is a real evil. It can suck both through dead sealing washers (copper or aluminum), and a small hole in any of the hoses of the fuel supply system. In general, the leak must be found and neutralized.
Fuel filters apply to both diesel and gasoline, if they have not been changed for a long time and are clogged, thrust from the engine can also not be expected.
2) Ignition system malfunction. Here it is worth determining whether your engine is troiting, if it is troiting then. If it doesn’t troit, then let’s start with a simple one, with a distributor. Firstly, it is worth spinning it on a running engine, trying to catch the moment (if there is such a thing, of course) when the engine will work more responsively. If it doesn't work out, look carefully at the wires and candles, and other electrical crap.
If you have an injection engine, start with the timing marks, because it is precisely from the correct installation of them that injection engine depends on the moment of spark supply and fuel injection. If the labels are in order, it is possible that one of the sensors has failed, of which injection motor darkness, starting with a mass air flow sensor, a crankshaft position sensor, a camshaft sensor, an idle speed sensor, ending with lambda probes and other electronic heresy, which you or the auto electrician you contact will have to check for performance.
If your engine began to pick up speed poorly after replacing the timing belt or chain, you may have made a mistake during installation, because here the tooth to the left, the tooth to the right plays a big role, an error of just one tooth can deprive you of the pleasure of pressing the pedal into the poly, instead of jerking from a place with slipping, you can get an uncertain displacement from a place with increased fuel consumption.
3)Air supply problems. Air leakage on the way to the cylinders after the mass air flow sensor is also fraught with a loss of power, because the computer calculates the composition of the fuel mixture based on the indications of the amount of air that the DMRV transmits to it, but if there is more air, then, as a result, a lean mixture and a weak thrust.
The air filter, it should be changed every six months, but there are smart people who do not change it for years. As a result, the air intake is difficult, black smoke, the engine is gaining momentum poorly and does not produce the required power. Replacing the filter solves the problem.
4) Exhaust problems. Before embarking on prose on this topic, I advise you to check the catalyst, if you still have it. If it is clogged, it's sad, there was a case on the Audi 100 C4, 2.3 engine, does not gain momentum, 4000 limit, they racked their brains for a long time, threw out the catalyst, the engine became like a beast.
I think it's not a secret for many that an engine without a muffler system produces 10-15% more power, so when tuning engines, they often put forward flow with an increased diameter exhaust pipes, but this is so, for the general development.
And now prose, a case from the recent past. The KAMAZ engine was brought for overhaul, the reason: there is no power and it is not gaining momentum. They opened the heads, and there the ass in general, apparently the engine ate oil well, and the oil burned out just in the exhaust manifold, in short, there was an unrealistically large amount of soot on the walls of the exhaust manifold, there was a hole with a diameter of 3-4 cm, it's like a person constipation, and without intervention from outside it is not treated.

In general, the engine can stop pulling for a variety of reasons - this is one of the most common malfunctions, which can have a huge variety of reasons, and below we will consider the most likely ones, describe their symptoms and explore this issue in detail. After all, one day it can happen to each of us that the engine will lose power, without being accompanied by any more symptoms. Probably the engine is not giving any obvious signs no illnesses, it seems to be almost perfectly fine and does not make any unusual noises and vibrations, but it just does not pull as well as it usually does. And the problem seems to be getting worse and worse every day, although you probably didn’t even notice when the engine started to pull worse for the first time.

If you are familiar with this situation, then let's look at the following reasons for reducing the engine's traction:

Poor quality fuel

First of all, you need to blame the fuel - remember where you last refueled - perhaps this is a new gas station or one with the fuel of which you had no experience of driving before. It is quite possible that this fuel simply turned out to be of very poor quality (it happens so much that you are just lucky if your engine just stops pulling - after all, for someone, the engine will probably stop starting at all until the owner completely replaces the fuel in the tank).

If you refuel at the gas station where you usually do, and nothing arouses suspicion, go to local communities on social networks, a car club in your region / district, or just a city portal - perhaps there was simply a bad delivery of fuel at the gas station.

However, most often, along with the loss of traction, the incompatibility of the engine with such low-quality fuel has other symptoms - for example, such as instability of engine speed, difficulty starting, and some others, depending on how bad the fuel turned out to be and on the car model.

But it is most likely that you can determine the poor quality of gasoline yourself by unscrewing the candles from the engine (this will require a special candle wrench) - in general, candles can often be used as the primary diagnostic method for certain malfunctions in the engine combustion chamber, since they are the ones that work most closely with this combustion chamber and at the same time are quick-detachable. If the fuel contains a large amount of metal-based additives, then the contacts of the candle and the "skirt" of the central diode will have a reddish coating (as if a red brick was crushed onto a candle).

Dirty air filter

Your air filter may also simply become dirty, in which case the elimination of power loss will cost you, perhaps, cheaper than all other options - just replace the air filter - you can either buy it yourself or replace it yourself.

The problem with a dirty air filter is that the fuel-air mixture that enters the combustion chamber of your engine cylinders enters there without enough air, and therefore the fuel does not burn completely, because it needs enough oxygen. It turns out a situation similar to a runny nose in a person - he seems to eat enough and leads a healthy lifestyle, but at certain points in his life (during illness with this runny nose), clogged nasal passages do not allow him to breathe normally.

Dirty or old spark plugs

Spark plugs can very well be dirty or excessively worn, in which case, if the engine is not pulling because of them, this is also a relatively inexpensive troubleshooting option - just clean the spark plugs or replace them. However, it should be borne in mind that both periodic fouling and wear of spark plugs is an abnormal process, and the reason for this lies, most likely, somewhere deeper, or in the spark plugs themselves.

Dirty fuel filter

The fuel filter, like the air filter, can cause loss of engine power. And the physics of the process here is similar to the air filter - if in the case described above the fuel did not completely burn out due to lack of air, then in the case of a contaminated fuel filter, on the contrary, an insufficient amount of fuel is supplied. In this case, it's simple.

Mechanical problems with the engine

If all the above methods did not save, and the engine still pulls the car badly, then it is time to entrust the matter to professionals - go to a good car service and diagnose the operation of the engine - checking compression (compression ratio in combustion chambers), for example, can tell a lot about work engine, including the approach to the limit of its resource and the upcoming costly repairs.

Fuel system malfunction

It is also quite likely that the reason for the drop in engine torque is a violation of the normal operation of the fuel supply system to the cylinders, and there may also be a number of reasons that the engine is not gaining momentum, let's list the main ones:

• A defective (dirty) fuel pump due to, for example, low-quality fuel or suction of gasoline from the bottom of the tank, where most foreign particles of dirt have settled.
• Faulty injector or oxygen sensor.
• Leakage in hoses or fuel supply pipes where air is sucked in.

Catalyst or exhaust system clogged

The cause of a decrease in engine traction can also be contaminated catalytic converter or highway exhaust system. In both cases, replacing the corresponding contaminated component will help. It should be borne in mind that the catalyst, as a rule, is very expensive due to the content of noble metals in it in certain quantities.

We have listed the main and most probable causes possible loss engine power - you need to remember that there are a great many such reasons, and if you were unable to install them yourself, then you must definitely go to a car service workshop to entrust this matter to professionals.

Sergei Kornienko

A fairly common reason for an engine to stop on the move is the lack of fuel. We will give examples when there was no fuel not only in the fuel tank, but also in the intake manifold. The simplest case is that there is no fuel in the tank. This situation most often occurs among young drivers. Mom and dad give their student son a car, sometimes even quite expensive. But the maintenance of the car, as you know, needs money and not small, at least you need to refuel the car. And the money is allocated to the son. But in a young head, the question immediately arises, isn’t it better to buy beer with this money and take a walk with friends? Since the answer is obvious, the car runs with a half-empty tank and sooner or later it will stall along the way. The second option: the young driver does not drink beer and fills up his car with the allocated money. But dad (or mom) allocates money based on normal operation cars, not considering that the heir can ride around the clock, it would be with someone. Gas is running out again. The following should be noted here: when there is little fuel in the tank, fuel pump forced to “grab” air along with the remaining fuel. When pumping such a mixture, all pumps, even diaphragm pumps on carburetor engines, wear out very quickly and eventually fail. In addition, when the fuel level is low, the pumps collect any dirt from the bottom of the tank, which increases the likelihood of filter clogging. In other words, for young drivers, the fuel system of the car, as follows from practice, is doomed to failures. (FIG. 9)

Rice. 9. Diagram of most electric fuel pumps.

1. Check valve. When it wears out, all the gasoline from the fuel rail flows back into the fuel rail within a few hours. fuel tank and the car doesn't start well.
2. Safety valve. Relieves the pressure of gasoline if for some reason it has become elevated.
3. Rear motor bearing.
4. Electric motor brush. Wears out much less than the collector. And when a hole appeared in the collector due to this wear, the brush warps and can jam in its brush holder. The motor will naturally stop.
5. Electric motor rotor.
6. Magnets glued to the case. When this magnet falls off, the electric motor either reduces its power or stops altogether.
7. Rear bearing.
8. Pump impeller. When checking the pump, if you reverse the polarity, this wheel may come loose and the motor will seize. However, if you reverse the polarity and lightly tap on the case, the wheel will spin back and the motor will work as if nothing had happened.
9. Receiving filter mesh.

However, it should be noted that electric fuel pumps are very rare (in our memory for 10 years, there is only one case per " Suzuki Escudo ”) fail on the move, so that the engine immediately stalls. They usually start to make noise and reduce performance and pressure, but the engine continues to run, although its power may be reduced. For engines with direct fuel injection, a reduction in power with a noisy electric pump will be necessary - it has already been checked more than once. regular car with gasoline injection, with a noisy pump, it will still work somehow, but at the next start, its engine will not start, since the fuel pump electric motor will be jammed (Fig. 9). Jamming occurs because the collector of this electric motor is worn out “to the holes” and its brushes no longer reach the collector contacts. And all due to the fact that the pump had to pump dirt from the bottom of the fuel tank, while grabbing air.

Diesel injection pumps also do not like dirt, air, as well as winter fuel. But if the injection pump with mechanical control bad fuel is somehow tolerated (“growl”, but tolerated), then high-pressure fuel pump with electronic control such a "cocktail" is not tolerated. On diesels Toyota ”, which have the letter “E” at the end of their name (“efish”, as car mechanics say), in this case the control valve plunger is jammed. Sometimes, before this, the engines lose their power, start poorly and absolutely, even when overloaded, do not smoke. Diesel car engines Nissan, Isuzu, Mitsubishi "with electronically controlled injection pumps, at first they will twitch and stall periodically, then one fine day they will also simply not start.

So, lack of fuel. A young man comes to the workshop and says: “Give me three (!) liters of gasoline, I’ve stalled on the contrary.” They explained to him that no one would give him gasoline here, handed him a canister (fortunately, after changing oils and coolants, there are a lot of them left in any workshop) and sent to the nearest gas station. The young man with the canister left. An hour later, another young man appeared and said: "Directly in front of your workshop, our car has stalled, start it." No one wants to quit work and go outside (besides, it is not known what tool to take with them), but the boring tone and perseverance of the petitioner do their job. We are coming. On the slope stands a pretty decent " Camry » 1996, and next to it is our first visitor (a beggar of gasoline). We ask if they found gasoline. “Yes,” they answer, “they have already filled it in.” A whole three liters. And it's in empty tank, the area of ​​​​the bottom of which is about 1.5 m 2, besides, the car was placed on a slope. They explained to the young people that when the car stalls due to lack of fuel, at least 10 liters must be poured into it. Otherwise, the fuel receiver located inside the tank in a special trough will remain dry. When the car moves, gasoline splashes inside the tank and, even if it is low, splashes into this trough, from where it is sucked in by the pump. In this case, even three liters of fuel in the tank, splashing, will get to the fuel receiver and allow the car to drive another couple of tens of kilometers. Three liters of gasoline poured into an empty tank standing car is nothing.

Another case. dragged " Subaru Legacy ” – stalled. We ask if there is fuel in the tank. They answer: "Yes, the light is not on yet." In fuel injected engines, you can quickly find out if there is fuel in the tank or not by pulling off the rubber return pipe and turning on the starter. At the same time as the starter is turned on, the electric motor of the fuel pump will also work (it can even be heard in the back of the car). Literally in a second or two, the fuel pump will raise the pressure in the fuel rail, forcing it to work pressure reducing valve, and a jet of gasoline will squirt out of the return line. For most machines, you can remove the return line even without a tool. We do all this - there is no gasoline. We go to a gas station (a client with a cell phone, therefore, is solvent), we bring 20 liters of gasoline, fill it up - the car starts. Having removed the instrument panel, we find that the emergency fuel level warning light has burned out. We change the light bulb - the car is ready. But three or four such "repairs" - and the client will have to change the fuel pump to his " Subaru ". After all, before stalling, the fuel pump is forced to pump gasoline along with air, and this, as mentioned above, wears it out very much.

Let's say you have fuel in your car's tank, but it still seems to you that the car won't start or stalls on the road due to lack of fuel. Although in the latter case, the car first reduces power, trying to press the gas pedal harder causes the car to twitch and then stop altogether, but at idle the engine still runs pretty well. Diesel engines also twitch when they run out of fuel. In addition, the value of their revolutions cannot reach the red zone on the tachometer and gradually decreases, being limited to 3000, 2000 or 1500 rpm. Below is no longer available. More about diesel vehicles we'll talk at the end of this section, but now back to gasoline.

Why does the car stall and not start? Perhaps this story will help find the cause. A pickup truck came to us for repairs Nissan Datsun » with petrol carburetor engine Z 20. At idle, the engine runs flawlessly, but if you press the gas pedal while driving, the car starts to twitch and, if you do not release the gas, it stalls. After 4 seconds, you can start it again and continue the “movement”.

The first thought about the reason causing this behavior of the car is that the receiving mesh in the carburetor is clogged. Absolutely all carburetors have a filter mesh in front of the needle valve. She is - The Last Frontier defense against dirt. Most often it is clogged with villi from the filter. fine cleaning(after all, it is paper, and if it is cheap, then, as a rule, it is of poor quality, from the filtering surface of which the pile constantly “flies off”).

But the owner of the car, an experienced car enthusiast, declares that he cleaned the mesh in the carburetor, as well as the receiving mesh in the gas tank, replaced the fine filter, went over the carburetor, checked and blew all the fuel lines. The pump of this car, although the engine is carbureted, like in cars with fuel injection, is electric, it is located in the gas tank and works. It seems that there is nothing to repair, and the car clearly does not have enough fuel. Here we noticed that the level of gasoline in the float chamber is 5-7 mm below the middle of the window. The meniscus of gasoline is visible at the very bottom of the window. They removed the float in order to bend its tongue and set the level in the middle, but it turned out that there was nowhere to bend the tongue: it was already pressed close to the body of the float.

Since the fuel level in the float chamber, as you know, also depends on the fuel pressure, for carburetor engines, after each change of the mechanical pump, this level must be adjusted. So, maybe in our case, problems with pressure? We connected a pressure gauge to the fuel hose - the pressure created by the electric fuel pump turned out to be only 0.15 kg / cm 2, and for the operation of carburetors, as you know, gasoline pressure is needed from 0.25 to 0.35 kg / cm 2 (for most models 0 .26-0.30 kg / cm 2).

They removed the gas tank, took out the pump, put it in order. The pressure rose to 0.27 kg/cm 2 and the fuel level in the sight glass rose slightly above the middle. We tried to ride - it turned out that nothing had changed. As long as you don’t press on the gas pedal, everything is fine, but as soon as you press it a little more than half, the car immediately starts to twitch and, if you don’t release the gas pedal, it stalls. There is no fuel level in the window anymore. We are trying to start the engine - there is no level, the car will not start. We pause for 3-4 seconds, turn on the starter - the fuel level appears, the engine starts, you can go. Until the next press on the gas pedal.

And then one of us comes up with a rather stupid idea to remove and check the fuel filter. Stupid because the filter was new. This was claimed by the owner of the car, and it was visible in the filter (beautiful and shiny). Removed the filter, began to blow through it in the direction of gasoline. By the force with which you can purge the fuel filter with your mouth, we usually conclude that it is working. For this, of course, some experience is needed, but this will come with time. If it takes too much to purge the filter great effort– the filter needs to be replaced.

In our case, when purging the filter, it turned out that something was moving in it. It turned out that as a result of poor-quality performance, the rigidity of the filter element was reduced. With a low flow of gasoline, this element kept its shape, and gasoline somehow, but passed through it. But as soon as the flow of gasoline increased, the filter element crumpled. And its plastic bottom blocked the outlet. The engine is stalled. Immediately, the pressure on both sides began to equalize, and after 3-4 seconds the filter element straightened out, gasoline could again enter the float chamber, and the engine would start.

So, if the carburetor engine stalls when you press the gas pedal, you should sequentially check:

· fuel fine filter;

· needle valve filter mesh;

· integrity of fuel lines;

· fuel pump pressure;

· the cleanliness of the float chamber and the fuel level in it;

· receiving mesh in the gas tank.

It should be noted that at faulty system ignition, the engine, when you press the gas pedal, also strives to stall - a so-called "gas failure" occurs. This phenomenon is caused by the fact that it is very difficult for an ignition spark to break through the spark gap when it is filled with a rich fuel mixture, which is formed when the gas pedal is pressed sharply. But at the same time, the fuel mixture is ignited unevenly. In some cylinders, the spark was able to break through the spark gap and ignite the mixture, in others it was not ... All spark plugs cannot be exactly the same, some spark plug will always fail first. The engine in this situation, when accelerating, simply troit. We call this phenomenon "fractional start". And it usually has nothing to do with fuel shortages. (FIG. 10)

Rice. 10. You can evaluate the spark plug as follows.

• The color of the lower insulator should be sand and the same shade for all candles of this engine.
• No traces of electrical breakdown should be visible on the upper and lower insulators.
• On the upper insulator at the place of seaming, no traces of exhaust gas breakthrough should be visible.
• The thickness of the side electrode must be the same along the entire length.
• The gap must meet the technical requirements.

If all of these tests are positive, then you can hope (only hope!) that the spark plug is working. A complete check of the spark plug can only be done on a special stand.

Cases are known when the flow of gasoline into the float chamber was limited due to the deformation of the fuel tank: the owner of the microtruck jacked up his car by placing the jack under the bottom of the gas tank. As a result, the bottom bent inward and pressed close to the fuel receiver tube. There was no receiving filter mesh on this car model, so the defect was discovered when they tried to blow through all the gas lines. The gas line to the fuel tank was blown through the mouth, removing the gas tank cap to hear the gurgling, but there was none.

If the car's engine stalls and you think it's due to lack of fuel, try topping up intake manifold about one tablespoon of gasoline (through the removed air tube or removed air filter). If you are right in your suspicions, then the engine will immediately start. This is true for all gasoline engines: both carburetor and injection. With fuel injected engines, we usually remove the air filter, pour gasoline directly on it, immediately put it back in place and then try to start the car. For carburetor engines, it is easier to supply gasoline directly to the inlet diffuser of the primary chamber (pouring onto air damper). It should be noted that when starting the engine with insufficient fuel supply, i.e. when running on lean mixture, there may be a flash of fuel in the intake manifold. And if there is something to burn, a small fire is possible. Therefore, pour gasoline into the intake manifold, assemble the air ducts normally and only then start the engine. In this case, even with loud pops in the intake manifold, there will be no fire. Especially well with such a "fire-fighting" method of starting, engines with central injection (single-point, TBI ). Therefore, just in case, when doing any repairs to the fuel system, keep a carbon dioxide fire extinguisher nearby.

When running out of gas (reduced flow through the injectors), fuel-injected engines first reduce power, then begin to twitch (especially when going uphill or when accelerating), and finally stall. It should be noted that if the oxygen sensor (s) in such engines are serviceable, then the control unit tries to compensate insufficient pressure in the fuel rail. On the signal of the sensor (sensors), the control unit sees that the oxygen content in the exhaust gases is too high, and immediately decides that it is too poor fuel mixture needs to be corrected. To do this, the computer increases (as far as possible) the width of all control pulses going to the fuel injectors. Therefore, the lack of gasoline in injection engines at first manifests itself differently than in carburetor engines, but with a further decrease in fuel pressure, the control unit can no longer cope with the adjustment, the engine will still reduce power and the car will start to twitch during acceleration, intending to stall. The jerking of the engine (and the whole car, if it happens on the go) is often accompanied by "shooting" into the intake manifold. We have a rule: if in some mode of engine operation “shooting” appears (pops in the intake manifold), then after checking the high-voltage wires and the ignition order, it is imperative to check the fuel system. After all, it is known that in all gasoline engines, when the mixture is too lean in the intake manifold, a flash of fuel occurs.

And one more note. While the engine is cold or has not yet warmed up to operating temperature, it requires much more fuel to operate than a warm one operating normally. The increase in the amount of this fuel is provided by wider control pulses to the injectors. And if, due to some defect, the fuel supply is limited, then, first of all, this will manifest itself on a cold engine. (FIG. 11)

Fuel pump all-wheel drive passenger car. 1 - electric pump; 2 - receiving mesh with calico weave, it is very difficult to clean it with compressed air, since it has very small cells; 3 – rheostat for the fuel level sensor; 4 - ejector pump (fuel from the "return" with its jet also draws fuel from the other half of the fuel tank, as a result, only one electric fuel pump can be used, although the fuel tank has two recesses); 5 - float.

As an illustration, we offer you three examples of a fuel system malfunction. In the first two cases, the owners noticed a drop in power and contacted the workshop before the cars began to stall, but this would definitely happen in a couple of days.

First example. Comes in for repairs Nissan Cedric » with a lack of power. The owner of the car formulates the problem as follows: “Everything is fine with the engine, but the automatic transmission is acting up: you pick up speed of about 60 km / h, and after that it’s as if someone is holding the car from behind, and the automatic transmission does not turn on overdrive". After long inquiries (apparently, the idea of ​​​​a malfunction of the machine was firmly hammered into the head of the owner of the car), it was possible to find out that the malfunction manifests itself only when driving uphill. We are doing a parking test. All is well, the engine, as expected, throws the tachometer needle at 2200 rpm. There really doesn't seem to be any issues with the engine. But the malfunction still exists, so we decided to drive his car with the owner. The car pulls off sharply and, quickly selecting the tachometer in first gear, immediately turns on the second one. In second gear, the intensity of acceleration almost does not decrease, and when the tachometer needle approaches 6000 rpm, third gear is engaged. At this time, a slight rise begins on the road, and the car “gets dumb” right before our eyes: its speed decreases, the machine switches to second gear, but there is no dynamics here either.

We slowly return to the workshop, turn off the engine and, having connected a tee with a pressure gauge to the fuel line (between the filter and the fuel rail), slightly covering the hood, we again leave for the road. The pressure gauge is brought to windshield, and its arrow is clearly visible to the passenger (mechanic). The car again vigorously starts to accelerate, on the pressure gauge about 3 kg / cm 2 (gas pedal in the floor), that is, everything is fine. Suddenly - the machine only had time to switch to second gear - the arrow crept down. The gas pedal is in the floor, the car is still accelerating, and on the pressure gauge it is already 2.5 - 2.2 - 2.1 kg / cm 2, the third gear is engaged, already 2 kg / cm 2, then 1.9 - the car is no longer “driving”. The second gear is switched on, the pressure is 1.8 kg / cm 2, the engine is none. We return. When we slightly release the gas pedal, the pressure increases. We return back to the workshop, turn on the “parking”, and the pressure gauge is already 2.6 kg / cm 2. A sharp press on the gas pedal - again 3.1 kg / cm 2, and the engine is running normally. We remove the pressure gauge, remove the fuel filter, we try to blow it with our mouth - to no avail. Clogged completely, although the car was somehow driving. We tell the owner that a new fuel filter is needed. To this he replies: "There is new filter, took it from a neighbor, ”and holds out plastic filter from carbureted car. I had to explain to him that the filter for carburetor machines also cleans the fuel well, but it is designed for a pressure not higher than 0.5 kg / cm 2 (for most Japanese carburetors fuel pressure at the inlet, as already mentioned, does not exceed 0.26-0.36 kg / cm 2). If such a filter is installed on a car with injection, then it can immediately burst. Or in an hour, for example.

After replacing the fuel filter, the defect disappeared, and the automatic transmission began to shift well. From this case, you can conclude that no automatic transmission will be able to work correctly with insufficient engine power, and no decent workshop will take an “automatic” for repair until it is convinced that the engine is at least approximately developing its passport power.

Second case. Automobile " Honda Accord » (petrol engine with injection and mechanical box gears) twitches on the rise. The impressions from the test drive are as follows. From a place, the car started off with turning the wheels and briskly, without problems, moved along a flat road, but it was worth low gear with the pedal in the floor, direct the car uphill and hold the gas pedal a little (the engine cannot instantly spin up on the rise), as powerful jerks followed one after another, and something clapped under the hood. The owner of the car, as soon as it began to twitch, immediately turned on an overdrive, since the box was mechanical, and the engine power allowed it to be done, and continued to move. There were no more fish.

Back at the workshop after the test drive, the first thing we did was connect a pressure gauge to the fuel system and start the engine. The manometer needle showed about 2.6 kg/cm 2 . Then they removed the vacuum tube from the pressure reducing valve and muffled it so that this pressure reducing valve would not “lubricate” the car with its actions.mud. The fuel pressure immediately rose to about the required 3.2 kg/cm 2 . Then we did the following: with the gas pedal we raised the engine speed to 5000 rpm and began to “play” the pedal briefly and sharply, so that the engine speed changed sharply from 5000 to 6000 rpm. Literally after a few seconds of such “gassing”, the pressure gauge needle dropped to 3.0 kg / cm 2, and then began to twitch. The pressure gauge is in the hands, its tube is rubber, and the arrow constantly twitches from 3.0 to 2.5 kg / cm 2. This alone is enough to suggest that the fuel filter (mesh) in the fuel pump inlet is clogged. With a working fuel system, the pressure gauge needle, if its body does not touch the engine or car body, should not twitch. If it twitches, then the damper device may not work. For Japanese cars this is unlikely as the air cavity damper is already built into the fuel filter housing. Sometimes, when installing a new non-standard (or fake) fuel filter, in which there is no air cavity, vibration from the operation of the fuel pump is transmitted to the body, but more often such vibration is observed when installing fuel system elements without regular insulating rubber gaskets. Therefore, it is more likely that the reason for the twitching of the pressure gauge needle was the stalling of the flow of gasoline that occurs when the intake mesh of the fuel tank is clogged. (fig12)

Rice. 12. Fastening the receiving mesh (filter) to the fuel pump. To remove the filter, you can simply pull off the mesh frame from the fuel pump with pliers. But the lock washer in this case is likely to fly away and be lost. Therefore, we first remove the washer with a small screwdriver, and then the frame of the receiving mesh itself.

By that time, we already knew that in Japanese cars there are two types of fuel-receiving strainers. One of them, an older design, uses a conventional nylon mesh, and such a filter can be easily cleaned by removing and blowing it with compressed air. Moreover, on the way, such a filter can be cleaned without removing it, just turn off the engine and shake the back of the car with your hands. The fuel in the gas tank will splash and, at least partially, wash away the dirt from the grid, after which you can continue to move. In a word, if just such a mesh filter is installed on your car, you can independently carry out diagnostics: if the car went “more fun” after you poured gasoline at a gas station (with the engine turned off), it is possible with a high degree of probability to assume that in the fuel there is dirt in the tank. When refueling, the gasoline in the tank is continuously mixed, and the debris from the receiving mesh is washed off, but remains inside the tank and after some time will return to the fuel receiver mesh (Fig.11 - see previous article: /item.osg?idt=71&idn=1324). How less fuel will be in the tank, the faster this will happen, and, having come to life after refueling, the car will again reduce its power. But the fact that after refueling, the engine power increases for a while, directly indicates the need to check the fuel tank and the receiving grid.

However, such mesh filters are less and less used in Japanese cars, giving way to the so-called filters with calico weave. These receiving meshes clean gasoline much better, but it is almost impossible to restore (clean) them with compressed air. For the first time such filters appeared on the cars of the company " Honda » 80s of production, and even then we came to the conclusion that when clogged, such filters need to be replaced with new ones. It used to happen that a car with fuel injection and low fuel pressure in the line came, they blew the intake grid with it (fortunately, the fuel pump can often be removed without removing the gas tank through the top hatch), and a week later the car returned with the same symptoms: no power, twitches, shoots into the intake manifold.

After that, decisive action had to be taken. They opened the trunk of the car, took out all the rubbish from it, removed the rug - there is a hatch under it. They opened it. Under it is another one, now in the gas tank housing. We disconnected the pipes and the electrical connector and took out the fuel pump along with the receiving grid and the float for measuring the fuel level - all this is attached to the hatch cover using special fittings. In our case it was Honda Accord ", but many Japanese cars have similar hatches different firms, they are located in the body of the car above the gas tank, so they can be found either in the trunk or under the back seat of the car: remove the pillow - and here it is.

Having taken out the pump together with the mesh, they pushed it out of the rubber retainer and bent it to the side, then with a flat screwdriver removed the metal spring stopper (in the form of a washer) from the end of the pump and separated the receiving mesh together with the frame (Fig. 12). Of course, you need to buy a new mesh, we tell all customers so, but until you find it ... Therefore, we cut off the filter mesh from the frame with scissors and cut the place where the mesh is attached to the frame with a flat screwdriver or a knife. Sometimes something breaks at the same time, but this is not scary, these breakdowns can be fixed with a soldering iron: all the machines that we have met have a frame made of polyethylene. Now a new filter is made from a brass mesh using scissors and a soldering iron and fixed to the frame instead of the standard mesh with the same soldering iron. This is how we delivered our Accord ” (as, indeed, many other cars) from jerking on the rise. But, using a brass mesh as a filter element, we significantly reduce the degree of fuel purification: the cells in the brass mesh are too large. Since this negatively affects the durability of the fuel pump and injectors, we always advise customers that they should definitely order a new fuel strainer for their car.

Thus, when the intake screen or fuel filter is clogged, the engine may stall, but before that it will twitch on the rise, not developing power, not developing speed. At idle, it will somehow work for some time (quite a long time), but then it will “die” after all. Although the whole sequence of these events can happen very quickly. Once they dragged it in for repairs Land cruiser "some big boss, to whom" well-wishers "dipped a tampon like" Tampax ". Apparently, they wanted to check whether it would really be like in the movies. So then the car suffered only a few hours, and then finally stalled. When they removed and opened the fuel tank, it turned out that the small tampon had absorbed about a third of the fuel and swelled, turning into some kind of porridge. So advertising the effectiveness of this product does not deceive.

If the car is equipped not with a submersible, but with an outboard fuel pump (these are mostly cars of the 80s), then first of all it is necessary to check if the conical filter in front of the fuel pump is clogged. This strainer is easily accessible using a bent wire by removing the fuel supply hose to the outboard pump. (FIG. 13)

Rice. 13. If under the car, most likely near the fuel tank, you find an outboard fuel pump, then with a probability of about 100%, we can say that there is a filter mesh at the inlet of this pump. To see and clean it, it is necessary to remove the rubber tube (4) from the pump inlet pipe (3) and look inside the pipe. The pump outlet is screwed with a union nut (2) to a metal pipe (1) because there is too much pressure. But there are no nets.

The last case that I would like to mention is related to the failure of the fuel pump. At the car" Toyota Crown » with 1 G engine - EU ran out of fuel. The guys rolled the car to the gas station with their hands and filled the tank. They began to start - the car will not start. It has already been mentioned above that draining the fuel tank is extremely harmful to the fuel pump and, in particular, to the electric pump of the injection engine. We repeat once again that gasoline, which contains air bubbles, leads to very rapid wear of both the pump itself and its manifold. As a result, the pressure developed by the pump decreases, and at the same time the probability of jamming of the armature of its electric motor increases. The stop of the electric motor occurs due to the fact that the brushes of the electric motor are wedged in the notch formed due to wear on the collector and electrical contact is lost. This is the most common cause of failure of Japanese fuel pumps. It is almost impossible to restore the anchor of the fuel pump motor. It's easier to buy another pump. It should be noted that in most cases the fuel pumps jammed after the engine was stopped. While the injection engine is running and therefore running electric fuel pump, the likelihood of the fuel pump jamming is very small. In at least 12 years, there was only one case where this rule was not observed.

So the car won't start. The guys turned out to be technically literate and immediately assumed that there was no fuel supply. To make sure of this, we opened the air filter cover, poured a couple of tablespoons of gasoline directly onto the filter element, after which the air filter cover was closed. They began to start the engine. The dead engine immediately "grabbed" and started, but after working for a few seconds and "eating" all the gasoline poured onto the air filter, it immediately stalled. When the operation was repeated, the situation repeated itself: the engine produces all the gasoline - and stalls. After that, deciding that something had happened to the fuel pump, the owners towed the car to us.

If you encounter a similar situation, remember the method described in one of the car magazines that allows you to drive to the garage on your own if the fuel pump fails. To do this, drain all the water from the glass washer reservoir and pour gasoline into it. Remove the tube from the washer nozzles and, having slightly opened, for example, the air filter cover, put the end of the tube into the air duct. By briefly turning on the washer and thus supplying fuel to the intake manifold, you can start the engine. As soon as it starts to slow down, turn on the washer again. So it is possible, although we have not tried it, to drive to the nearest workshop on our own. Just do not forget that if you apply more gasoline than necessary, the engine will also begin to slow down and may even stall from too rich a mixture.

When the car was rolled into the box, the first thing we did was remove the “return” pipe from the pressure reducing valve on the fuel rail (this can be done even without a tool) and slightly “pulled” the engine with the starter: gasoline did not appear from the pressure reducing valve nipple, which means it is not in the fuel rail either. There are cases when there was no gasoline in the "return" because the pressure reducing valve was jammed. In this situation, the engine started and ran, but it had an increased consumption of gasoline due to the fact that there was too much fuel pressure in the fuel rail. They loosened the check valve nut on the fuel rail (on this engine, gasoline is supplied through check valve), once again “pulled” the engine with a starter - there is no gasoline. Then they removed the back seat and found a hatch that included wires. With the help of a control light, we found the wires that power the electric motor of the fuel pump (usually they are thicker than the wires of the level sensors, but there are wires that are the same in diameter). To do this, the "crocodile" of the control bulb must be connected to the car body and then turn on the ignition. Now, with the sharp tip of the “control” probe, you need to determine the wires in which there is voltage. Most likely, these will be power and signal wires from the fuel level sensor. Voltage-free wires are “grounds” and fuel pump power. Now, using the same "controller", it is necessary to determine the wire on which the voltage appears when the starter is turned on. This will power the fuel pump motor. Without voltage, the “ground” wires will remain, of which the thickest is the “ground” for the electric motor. However, the "mass" can always be "taken" from the car body.

After checking the wires, we determined that when the starter is turned on, power is supplied to the gasoline pump, but gasoline to the fuel rail is not. Yes, and the noise from the operation of the fuel pump is not audible at all. It should be recalled here that if, while driving, you hear the sound of a running fuel pump, then this fuel pump will soon break down (i.e., jam). A good fuel pump runs almost silently.

So, we found out that the pump is powered, but it does not work. Hence the conclusion: the fuel pump is stuck. In this situation, you should do this: one person turns on and holds the starter, and the second at this time hits the pump with something heavy. This is easy to do if the pump is suspended: just lightly tap on its body with any key, and it will work. If the pump is submersible, as is the case with most Japanese cars, and, therefore, is located in the gas tank, it is very difficult to hit its body. In such cases, you can try to hit (and harder) on the gas tank. The blow should be strong, the pump jamming should be weak, the gas tank should not be plastic. It is quite possible that the vibration from the impact will reach the electric motor of the gasoline pump, and it will start to rotate, shuddering, because the wedging of submersible gasoline pumps from hitting the gas tank is a fairly common phenomenon. We were unlucky: a couple of hard blows with a hammer on the gas tank did not revive the engine. I had to use another method: we disconnected the fuel pump power harness connector and, through additional wires, supplied power from the battery to the fuel pump electric motor, first in one polarity, then in the other, and so on several times. With each voltage supply, the armature of the fuel pump electric motor, depending on the polarity of the supplied voltage, jerked first in one direction, then in the other, and on the second or third connection the motor suddenly started working. We just need to connect the connector in place and start the engine. We told the owner of the car the following: “The engine, as you asked, we started, but the fuel pump is faulty and needs to be changed. Today the engine started, maybe it will start tomorrow, it will work for a week or two, but at the most inopportune moment you will not be able to start it again due to the fuel pump electric motor jamming. But on the go, most likely, it will work properly.

From the foregoing, it follows that you can try to wedge a stuck submersible gasoline pump by hitting the gas tank or applying alternating voltage of different polarity to the electric motor of the pump, but in general, such pumps must be changed. (FIG. 14)

Rice. fourteen. Removing the electric fuel pump (3). As you can see, instead of this fuel pump, you can insert any other, even a different size. After all, you can always screw the fuel pump housing with wire and shorten the tube (1). Almost all pumps, regardless of size, have the same parameters. However, we had a case when a 4.5 liter Cruiser, according to the driver, after installing a pump from a 1.3 liter Corolla, became more “stupid”, but more economical. When installing a "non-native" pump, you can also replace the rubber hose (2) with another one of the appropriate length.

When replacing the fuel pump of gasoline engines, the following considerations should be followed.

The pump can be anything, from any car, even from a domestic one, the main thing is that it is designed to work with an injection engine. In the end, you can also fix it in the gas tank on a standard bracket with wire. We had a problem with the choice of a pump only once, and even then not with Japanese car. For 5 liter american jeep we installed a pump with a 1.5 liter " Toyota Corolla ". According to the owner, a decrease in power was noticed on the slopes, but the car became very economical.

12 volt power is supplied to all pumps all the time while the starter is on or while the command is coming from the unit EFI (engine control unit). For engines with a mechanical air flow sensor (vane type), the command to start the electric pump is formed by closing the contacts in the “counter” itself when its damper (blade) is deflected, which is deflected by the air flow generated during the rotation of the engine. In most engines, the fuel pump electric motor includes an engine control unit (block EFI ) when it receives pulses from the crankshaft speed sensor. The engine rotates - power is supplied to the electric motor of the fuel pump. The engine stops, power is supplied for a couple of seconds, and then disappears.

A serviceable fuel pump must create a pressure of at least 4.0 kg / cm 2. In practice, we do not put on a car a pump that "presses" less than 4.5 kg / cm 2. A pump that creates a pressure of 5-6 kg / cm 2 is considered good. We check the pumps (which are new only for the machine being repaired, since they come from dismantling) as follows (Fig. 14). Pour a quarter of a bucket of gasoline. With a rubber tube of a suitable diameter, we connect the nozzle of the pump under test with a pressure gauge having a limit of 10 kg / cm 2 (deaf). We connect two wires about 1.5 meters long to the pump outputs. We lower the pump into the bucket. Gasoline must cover the pump housing by at least a third. For 2-3 seconds we connect the wires to the battery and look at the pressure gauge. We change the polarity, turn on the pump again and look at the pressure gauge. If the polarity is wrong, there will be no fuel pressure or it will be insignificant (1-2 kg / cm 2). With the correct polarity, the pressure will be more than 2 kg / cm 2. If you have an excellent pump, do not wait until the pressure gauge needle stops after turning on. If it showed more than 5 kg / cm 2, immediately stop checking and be glad that you got such a good fuel pump. After all, what you wanted to know - whether the pump is working or not - you found out that the pump is pressing, and testing the reliability of the connections, sparking with wires at the battery terminals, when there are a lot of gasoline vapors around, is completely useless.

There are three types of electric petrol pumps. The first is designed for carburetor engines, the pressure it creates does not exceed 1 kg / cm 2. Usually these pumps are diaphragm pumps, but centrifugal (vortex type) are also found. It should be remembered that when replacing a gasoline pump in a carburetor engine, the supply pressure changes (though not much) and, therefore, the fuel level in the float chamber changes. Therefore, after replacing the fuel pump, you need to check the fuel level in the float chamber. The second type of gasoline pumps is electric, for engines with electronic fuel injection. Them maximum pressure does not exceed 6 kg/cm 2 . Gasoline pressure in the fuel rail, i.e. injection pressure is determined not by the pump itself, but by a special pressure reducing valve, usually located on the same rail. All gasoline, no matter how much the fuel pump supplies, it dumps back into the tank, leaving pressure in the fuel rail from 2.3 to 3.1 kg / cm 2, depending on the brand of engine. The main thing is that the fuel pump presses more than 3.1 kg / cm 2 (when measuring the pressure in the fuel rail) and there is enough fuel for the injectors at its maximum flow rate. On engines with direct injection of gasoline, pumps of this particular (second) type are installed. The third type is electric pumps for mechanical injection. This injection was used on old Mercedes, Volvo, BMW, etc., on known to us Japanese cars this type of injection was not met. Pumps of this type must push about 9 kg / cm 2, since operating pressure in the engine about 5-6 kg/cm2. These pumps, of course, can be used on Japanese cars, the pressure reducing valve will dump all excess gasoline back into the tank, but they are usually (used) very noisy, expensive (well, after all, Mercedes!) And short-lived.

Before installing the pump, you should figure out where it has a positive terminal, and where it has a negative one. This can be determined by checking the pump at the battery terminals, although usually the plus and minus signs are engraved near each terminal, but, especially if the pump is not standard, it is harmless to check whether these inscriptions correspond to reality. Mark on the pump housing where is “plus” and where is “minus”. When you fix the pump on a standard bracket, then connect the “minus” to the bracket body (for most “Japanese women” it is metal), and the “plus” to a thick wire insulated from the body. If the polarity is wrong, the pump will work, but will not be able to provide required pressure supplied gasoline. True, sometimes, with the wrong polarity, the nut securing the pump impeller is unscrewed and the pump jams. But it is worth supplying power in the correct polarity, the nut itself is screwed back and the pump works.

But the most difficult defect in the fuel system to diagnose, perhaps, was the following. They drag the car in tow with gasoline engine. What model it was has already been forgotten, and it doesn’t matter, the main thing is that it was with multi-point injection ( EFI ) and the fuel pump was in the tank. We start it - it works somehow. It shakes, shoots at the intake manifold, when you try to press the gas pedal, it stalls. There is a lack of fuel. We connect the pressure gauge to the fuel rail - really 1.5 kg / cm 2, which is much less than the norm. With the help of pliers, we pinch the return line, turn on the starter - nothing changes on the pressure gauge. All the same 1.5 kg / cm 2 We disconnect the return line, turn on the starter - no fuel flies from the return line. This means that the matter is not in the pressure reducing valve (the return line was attached directly to the pressure reducing valve and if this valve was jammed in the open position, all gasoline would be dumped back into the fuel tank, and there would be no required pressure in the fuel rail; such cases, although very rare, but meet). We remove the fuel filter - make sure that it is not clogged and almost new. We remove the fuel pump and make sure that the receiving mesh is clean. We lower the fuel pump into a bucket full of gasoline and, by connecting a pressure gauge, we make sure that it is in good condition - a pressure of 5.5 kg / cm 2 is more than enough. It remains to blow the fuel line. Blown away. Clean. In other words, they checked everything and it's all right. We assembled the entire fuel system in place, we are trying to start the engine - the picture is the same. Symptoms of lack of fuel and pressure in the fuel rail are almost non-existent. Everything was taken apart and checked again. Everything is fine. Then they fixed the fuel pump on its fittings, but did not lower the pump into the tank, but lowered it into a bucket. The bucket was placed on the side of the engine and a hose was thrown from the fuel rail to the fuel pump fitting. So we excluded the fuel filter and the gas line from work. Power was supplied to the pump, and the defect became clear to everyone. There was a hole in the short hose from the fuel pump itself to the fitting. And since there was a textile winding on top of this short hose, gasoline did not spray in a jet, but, as it were, flowed down the hose down to the fuel pump housing in a stream. And at first glance, this flow of gasoline was almost invisible. But because of him, there was no pressure in the fuel rail. Gasoline almost did not reach her. If, during the first check of the fuel pump, the pump with all the fittings was lowered into the bucket, i.e. and with a tube, this defect would most likely have been discovered sooner. (PIC15, PIC16)

Rice. fifteen. If the rubber hose (1) breaks, find the cause low pressure fuel in the fuel rail is very difficult. Moreover, replacing the fuel pump (2) does not give anything, and we do not purchase these pumps new, but from disassembly.

Rice. 16. Appearance a modern fuel pump with a receiving mesh, which has a cotton weave. It is extremely difficult to clean such a mesh qualitatively.

Concluding the conversation about fuel problems with gasoline cars I would like to make one more point. Many all-wheel drive (4 WD ) cars Japanese made the fuel tank is located above the cardan shaft (under the rear seat). In this case, the gas tank, as it were, consists of two parts - a tunnel is arranged in its bottom for cardan shaft. The fuel pump, together with the fuel receiver, is located in one half. In order to develop fuel from the other half, another pump is used, an ejector type. The operation of this pump is provided by a jet of fuel from the "return". From the fuel rail, excess fuel does not return directly to the trough around the electric fuel pump, but first goes to the ejector pump, where it captures some more fuel from the other half of the tank, and only then is fed into the trough. When the regular fuel pump is bad, the flow in the "return" turns out to be weak and the ejector pump almost does not work. As a result, gasoline is not completely produced from one half of the fuel tank. Of course, something flows when gasoline in the tank sloshes on the go, but all the same, the car in this case carries with it, though not a large, but unused fuel supply (FIG. 17).

Rice. 17. Typical fuel supply scheme for all-wheel drive sedans. The complexity of this scheme is that the fuel tank (4) has a recess for cardan shaft(6) and, therefore, there are two recesses at its bottom. Therefore, to use all the gasoline, two pumps are required. One electric and one ejector. For work ejector pump a jet of fuel from the overflow (return) line is used, to create which you need a good electric pump, serviceable fuel filters and a pressure reducing valve on the fuel rail. 1 - fuel return line ("return"); 2 – fuel supply line; 3 – fuel transfer line; 4 - fuel tank; 5 - receiving grid; 6 - recess in the tank under the cardan shaft; 7 - electric fuel pump; 8 - ejector fuel pump; 9 - filler neck; 10 - ventilation line.