Too rich mixture: causes and remedies from professionals. The engine does not pick up speed Why is there not enough fuel

Sergey 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 half empty tank and sooner or later along the way it will stall. 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 out fuel rail flows back into 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 generated pressure, but the engine continues to run, although its power may decrease. For engines with direct injection fuel, 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 somehow endure (“growl”, but endure), 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 (there are a lot of them after changing oils and coolants in any workshop) and sent him 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 the pressure reducing valve to work on it, and a stream 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 push 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. On Idling 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 - 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 car owner seasoned 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. Full check spark plugs can only be made at 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 ignite 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 gasoline runs out (its flow through the injectors decreases), fuel-injected engines first reduce power, then begin to twitch (especially when driving 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. Based on the signal from the sensor(s), the control unit sees that the oxygen content in exhaust gases 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 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 high voltage wires and ignition order must be checked 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 not yet warmed up to operating temperature, it requires much more fuel to operate than a warm one operating in normal mode. 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 automatic transmission the gears are junk: 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 machine 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 a plastic filter from carbureted car. I had to explain to him that the filter is 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 replacement 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 not a single 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 flat road but it cost 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. In one of them, more old design, a conventional nylon mesh is used, 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 your hands back car. 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 they can be restored (cleaned) using compressed air almost impossible. 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 with the help of special fittings. In our case it was Honda Accord ", but many Japanese cars have similar hatches different firms, they are located in the car body above the gas tank, so they can be found either in the trunk or under back seat 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 tell 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 the metal pipeline (1), because there is too much great 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. As long as the injection engine is running and therefore the electric fuel pump is running, there is very little chance of the fuel pump getting stuck. 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 come across similar situation, remember described in one of automotive magazines a method that allows you to drive to the garage on your own in the event of a malfunction of the fuel pump. 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” tube 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 he had increased consumption gasoline because 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 help control light 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 fuel 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 connector of the fuel pump power harness and supplied power from the additional wires. battery to the electric motor of the fuel pump, 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. 14. 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 air flow generated during engine rotation. In most engines, the fuel pump electric motor includes an engine control unit (block EFI ) when it receives pulses from the speed sensor crankshaft. 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 the fuel pump at carburetor engine the supply pressure changes (though not much) and, consequently, 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 injection fuel. Their 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 on the battery terminals, although usually the plus and minus signs are engraved near each terminal, but, especially if the pump is not regular, 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 regular 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 multipoint 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. 15. If the rubber hose (1) breaks, it is very difficult to find the cause of low fuel pressure in the fuel rail. 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. To operate the 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.

For the engine to develop full power, the following conditions must be met:

1 - good engine compression;

2 - stable and plentiful supply of fuel;

3 - a large number of air.

If one of the above conditions is not met, then Engine efficiency will be low.

When traction is lost under load, this means that the engine control unit has switched to emergency mode. Emergency mode engine operation is provided for all modern machines. This mode is necessary so that the car does not quickly, but safely reach its destination.

To find the right reason I need to do computer diagnostics of the engine.

According to the results computer diagnostics we will understand in which direction to move and where to dig in order to find out the true cause of the malfunction.

If diesel the engine does not have enough fuel then check fuel equipment: .

If the diagnosis shows that diesel fuel enough, but the turbine is under-blowing and there are no errors in other systems, then it is advisable to measure the engine compression.

Lack of proper engine compression will result in the engine will not pull and develop full power. If there is no piston compression, but there is enough air and fuel, then a strong explosion will not happen anyway, thus there will be no good exhaust, and as we know, the exhaust spins the turbine, so the turbine will not inflate the required amount of air. Lack of air boost will cause the car to not pull.

The most common reason for lack of airflow- problems in the operation of the turbine and shutdown of the turbine itself.

Consider an engine with variable geometry turbines (the most common).

Turbine shutdown is usually due to one of two problems: one is related to air, the other is related to mechanical failure the turbine itself (impeller wear, axle play).

There are variable geometry turbines that are controlled by vacuum, and there are those that are controlled by an electronic actuator.

The machine has four sensors that fully affect the operation of the turbine.

1 - Boost pressure sensor. It will measure the air pressure in the intake manifold.

2 - Boost pressure regulator. This is a valve that controls the geometry, i.e. turns the turbine on and off.

3 - Temperature sensor intake air. Shows the temperature of the air entering the motor.

4 - Atmospheric pressure sensor. Measures the atmospheric pressure where the vehicle is moving (normal atmospheric pressure relative to sea level).

Most often it happens that the tightness of the air intake system is broken in the car. Thus, the turbine drives all the air out (the pipe is torn, the connection is poor at the joints, the intercooler (air cooling radiator) is cracked).

To identify such a problem, you need to check all intake system air for tightness.

Next most common problem: Faulty geometry in the turbine.

To check the geometry on the car, you need to remove the vacuum hose from the actuator on the turbine itself. Put another hose on it and try with your mouth or special device draw in air. After this procedure, the stem that controls the geometry must change its position. If it does not change its position, then there may be 2 reasons, either the membrane in the actuator is torn, or the geometry itself is jammed.

Failure of the boost pressure regulator and boost pressure sensordetected by the presence of errors in them in the results of computer diagnostics.

The boost pressure regulator can also be checked with a vacuum gauge.

Don't forget to check Vacuum pump And vacuum tubes throughout the machine for tightness. This is done as follows, disconnect the pipe in some place, put your hand on it, you should feel air being drawn in.

A turbine with an electronic actuator is checked only with the help of computer diagnostics!

Please note that "swirl" flaps (not available in all vehicles) can also affect the loss of traction.

We hope that this information will help you identify the reason why your car is not pulling or gaining full power, as well as gaining enough knowledge to communicate with car service specialists.

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 consider the following reasons reduction of motor thrust:

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 still just lucky if your engine just stops pulling - after all, someone probably has the engine won't start 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 raises suspicions, 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 to determine poor quality you can use gasoline yourself by unscrewing the candles from the engine (this will require a special candle key) - in general, candles can often be used as a primary diagnostic method certain malfunctions in the combustion chamber of the engine, since it is they who most closely cooperate 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 coating reddish color(as if a red brick was crushed onto a candle).

Dirty air filter

You may also simply have your air filter dirty, in which case eliminating the power loss will probably cost you less than all other options - just change the air filter- You can either buy it yourself or replace it yourself.

The problem with a dirty air filter is that fuel-air mixture, which enters the combustion chamber of your engine cylinders, enters there without a sufficient amount of air, and therefore the fuel does not burn out completely, because for its combustion it is necessary 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 is similar here air filter- if in the above case the fuel did not burn completely due to lack of air, then in the case of a contaminated fuel filter, on the contrary, fuel is supplied an insufficient amount. 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 - stop by good car service and diagnose the operation of the engine - a compression check (compression ratio in the combustion chambers), for example, can tell a lot about engine operation, including the approach to the limit of its resource and the upcoming costly repairs.

Fuel system malfunction

It is quite probable that such a reason for the drop in engine thrust, as a violation normal operation fuel supply systems to the cylinders, and here it can also be whole line the reasons that the motor 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.
• Malfunction 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 catalyst, as a rule, is very expensive due to the content of precious metals in it in certain quantities.

We have listed the main and most likely 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 definitely need to go to a car service workshop to entrust this matter to professionals.