Why does the car start badly after replacing the fuel filter. Why the fuel pump does not pump gasoline Does not start after replacing the fuel pump

One of the most important elements is the electric fuel pump, which is located in fuel tank car. The fuel pump pumps fuel into the system from, creating a certain pressure.

Automotive repair professionals identify the following common problems: fuel system that are connected to the fuel pump:

the fuel pump pumps poorly and does not create the necessary pressure;
the fuel pump does not pump when the ignition is turned on;

Given that the fuel pump is an electromechanical device, the most common fuel pump malfunctions are related to both mechanical and electrical parts. Next, we will consider what signs indicate a breakdown of the fuel pump and why the fuel pump stops pumping partially or completely.

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Signs of a bad fuel pump

The main symptoms of the failure of the fuel pump, as well as failures in its operation, are:

the car starts with difficulty, the engine is unstable, there are dips, jerks when you press the gas pedal, etc .;
the pump does not pump after the ignition is turned on, and the fuel pump does not pump, the engine does not start;

There have also been cases when the fuel pump stops pumping right on the move. The engine in such a situation begins to malfunction and stalls immediately after the remaining gasoline in the fuel line. The problem can occur both regularly and periodically.

The fuel pump does not pump: causes and diagnosis

Let's start with the fact that if the gas tank is full, charged, dry and there is a spark on them, the starter turns the engine normally, but the engine does not seize, then you should pay attention to the fuel pump. Frequent problem is that there is no power to the fuel pump after the ignition is turned on. In a similar way, the malfunction also manifests itself in motion, when the power to the fuel pump is lost and the engine suddenly stalls.

An equally important point is how much the fuel pump pumps. In other words, the pump may hum and buzz (power is supplied), but not create the desired pressure in the fuel line. The pressure in the fuel system with a working fuel pump must be more than 3 bar (depending on the specific car model). The indicated pressure is accumulated in the fuel rail and has an indicator of 300 kPa and above.

To check, it is necessary to measure the pressure in the fuel rail with a pressure gauge, taking into account the indicators that are the norm for a particular car model. On the example of injection VAZs, the pressure when the ignition is turned on is 3 atmospheres, at idle the indicator is 2.5 atmospheres, when the gas is pressed 2.5-3 atmospheres. This method will help to accurately determine:

malfunction of the fuel pressure regulator in the rail;
breakdown of the fuel pump or a noticeable decrease in its performance due to wear;
severe contamination of filters (fuel filter and / or fuel pump mesh);

In the second case, when you press the gas, the pressure does not increase, in the latter case, the pressure gauge needle rises, but very slowly or jerkily.

A decrease in the pressure indicator below the norm will lead to the fact that the engine may not start or start with difficulty, triple, twitch, work unstably and with failures. If this is the fault of the pump, and not fuel filter, then there is a high probability that the coarse mesh of the fuel pump is clogged. In this case, there is no need, since it will be enough to replace or even clean the mesh.

If there is a suspicion that there is no voltage to the fuel pump, there is a way to quickly check. It is enough to turn the ignition key and listen, since at the moment the key is turned, a slight hum of the fuel pump should be heard. If such a buzzing is not heard, then there is no power to the fuel pump, there are problems with the wiring, etc.

We add that this method of determining the operation of the pump by sound is not suitable for all cars. On some models (especially the premium class), the sound insulation is at a high level and the fuel pump turns on immediately after opening the driver's door, and not when the key is turned in the lock. In this case, it may seem that the fuel pump does not work when the ignition is turned on, while
the sound of the pump can simply not be heard.

Also in the general list possible causes, through which the fuel pump does not pump, are marked:

failure of the fuel pump fuse;
breakdown of the fuel pump relay;
problems with the "mass" of the fuel pump;
malfunction of the electric motor of the fuel pump;
oxidation or a hall of contacts and terminals of the fuel pump;
the fuel pump itself is faulty;

Wiring to fuel pump

On most cars, the wiring to the fuel pump consists of three wires: "plus", "minus", as well as a wire for indicating the amount of fuel in the gas tank. If the fuel pump is not pumping, then the cause may be a lack of power.

To check the power to the fuel pump, it is enough to take a 12-volt light bulb by supplying power to it from the external connector of the fuel pump. After turning the ignition, the control lamp should light up. If this does not happen, then the problem is in the external circuits. When the lamp comes on, it is necessary to check the internal contacts of the fuel pump.

To check the external wiring, alternately connect the positive and negative contacts that are removed from the fuel pump power connector to the pump ground. Contacts must also be connected to the fuel pump relay. If you place a negative contact on the ground, after which the ignition is turned on and the light comes on, then this means that this contact is faulty. In the event that the light bulb did not light up, then problems with the "plus" are obvious. If you place a contact on the relay and the light turns on, it is likely that the wire is damaged on the segment that connects the relay and the fuel pump itself.

Fuel pump electric motor

If checking the pressure in the fuel rail and external wiring to the fuel pump gives positive results, then the fuel pump motor should be checked. The specified electric motor is responsible for the circulation of gasoline inside the fuel pump.

During the check, it must be borne in mind that the terminals on the fuel pump themselves tend to oxidize, as a result of which power is not supplied and the pump does not pump. In this case, the motor is working, but the terminals need to be cleaned or soldered.

To believe the fuel pump motor, you will need to fix the wires of the control lamp to the cleaned and serviceable terminal of the electric motor, after which the ignition should be turned on. If the light comes on, it indicates that the fuel pump motor is not working.

Fuel pump ground contact

Problems with the mass of the fuel pump may be indicated by a fuel level sensor that does not work correctly. The mass may be poorly fixed, in this case the fuel pump does not pump fuel. The ground wire is usually under dashboard and walks through the salon. It is necessary to find the indicated wire, check and clean all the contacts, then securely fix the mass on the fuel pump.

The fuel pump relay is often mounted next to the fuel pump ground, that is, under the dashboard. A normally operating relay after turning on the ignition in a couple of seconds allows the pump to create pressure in the system and immediately turns off.

At the moment the ignition key is turned, the driver hears a characteristic click (the relay is turned on), then a similar click will indicate that the fuel pump relay is turned off. If such clicks are not heard, this indicates a malfunction of the relay or its contacts. The best solution is to replace the fuel pump relay with a new or known-good device. We add that the cost of spare parts is quite affordable.

Fuel pump fuse

During diagnostics, be sure to check the fuel pump fuse. The specified 15 A fuse is usually located in the fuse box in engine compartment and is marked FUEL PUMP, which in translation means fuel pump.

The fuel pump fuse must be pulled out and inspected. The integrity of the contact will indicate that the device is normal. A damaged contact will indicate that the fuel pump fuse has blown. In this case, you need to install a new fuse, which has a very low cost(as in the situation with the fuel pump relay).

Other causes of fuel pump malfunctions

Quite often, unprofessional installation of additional electrical equipment or security anti-theft systems leads to the fact that the power to the fuel pump is lost due to reversed contacts or other connection errors.

Also, one should not exclude the possibility that a failure occurred in the car alarm or security complex, after which the fuel pump power is blocked. In other words, .

Finally, we add that the gasoline pump in the gas tank is immersed in gasoline, in which it is actively cooled. The habit of driving with an empty tank can quickly disable the fuel pump electric motor, as it burns.

harmless problem

Changed the fuel filter, after which the car will not start? Check the dimensions of the new filter device. A slight deviation of up to 0.2 cm in height (not diameter) of the filter element can become a prerequisite for the appearance of the designated task. Why does the engine start poorly after replacing the fuel that the car does not start the pump and. The filtering device operates under the highest pressure, which is calculated by the dealer vehicle- the parameter affects the operation power unit. The use of an inappropriate filter element will lead to a change in pressure in the system, the car will stop starting. Why after replacing the fuel filter. Car won't start after changing fuel filter... You can get acquainted with the dimensions that the filter must meet and with the sequence of its replacement in the vehicle operation book.

It is possible to find out if a new filtering device is the cause of a poor start of the motor in this way:

Pump defective?

If you chose a fuel filter, according to the requirements of the car manufacturer, corresponding in size, installed it, and the car stopped starting - check the manual priming pump, it may be the cause of the air system. After replacing the fuel filter. To solve the problems associated with the specified unit, the following methods will allow:

It is bad to start after replacing the fuel filter w203 cdi 220 mercedes-benz

air that enters the system after several attempts to start car goes back on its own.

After replacement fuel filter- engine start up not normal!!

The engine started well. From the first time.

Bleed the pump several times, provided that the unit is in good condition. Won't start after fuel change Won't start after fuel change Car before me. At the same time, the car will start to work normally if the plug was not over the entire section of the pipe.
You can get rid of the formed air lock by blocking the drains of the filtering device and removing a little volume of fuel from the system using a pear (you can use your mouth). If, after these manipulations, the fuel flows into the return line, the system is airless. Are you having problems after after-sales service car? The article will describe possible problems after replacing the fuel filter, why the car does not start. Hello everyone…. And today we will burn down what to do if the car does not start after replacing the fuel filter? Otherwise, look for the cause of depressurization.
To obtain excess pressure, remove the hose located between the tank with the filter element and the pump, then supply air to the tank, then quickly reinstall the hose and start the engine. If the problem persists, replace the pump.

Airiness of the system, as well as malfunctions in operation pump manual pumping is not always the cause of failure.

Other reasons

Changed the fuel filter, after that the car does not start well? Pay attention to the quality of the new filtration device. The fuel filter is consumable requiring periodic replacement. After replacing the fuel filter, the car will not start. from quality and design features unit depends on its price. The car does not start well after replacing the fuel, the car does not start? pump. If you are offered to purchase a filtration element at a reduced price, most likely this is not an original product, but a fake. Using a low-quality device can damage the motor. For example, during fuel supply, the filter curtain will break, or its porosity is too large. These factors will lead to a deterioration in the filtering of harmful particles from the fuel, and will provoke a breakdown of the auto engine. After replacing the fuel thread below and the car will not start and the pump button. Consider diesel fuel filters are more expensive than the indicated devices for gasoline-powered vehicles. Diesel filter devices produce not only mechanical cleaning. Won't start after replacing fuel pump. After replacement Fuel Machine won't start Replace fuel pump c. They prevent water from entering the system, and at sub-zero temperatures they provide heating of the fuel (to avoid the formation of paraffin crystals).

Bleed the fuel system.

The fact is that the fuel filter can have a significant volume (sometimes 0.5 liters) and for a single start, the pump simply does not have time to pump the system. Accordingly, there is not enough fuel and the engine cannot start.

On injection and modern diesel vehicles it is necessary to open the lock 3-5 times to the “ignition on” position (do not turn the starter) and wait 5 seconds.

For clarity, watch this video:

On older diesel cars it is necessary to pump the system with the help of the so-called. pears. As a rule, those who drive such cars themselves know and are able to do all this, but if you are just mastering old diesel engines with a mechanical injection pump, this video will be useful to you:

On the carbureted cars (although they haven’t been produced for 10 years already), it’s still easier - just pump up fuel and hoses by pressing the petrol pump lever 10-20 times. If the lever does not move, simply crank the engine with the starter ½ turn.

Bleed the system and try to start. If the engine starts, everything is fine, if not, we begin to remember what we did and look for mistakes.

If the filter is external.

As a rule, in systems with an external fuel filter, there are two filters! Filter fine cleaning, as in the picture above and a coarse filter, it is on the fuel intake in the tank. If you haven't replaced it, replace it. The main problem, the engine does not start, after replacing the fuel filter lies in the hoses! Poor-quality hoses swell, and since they are held on the outside by a braid, they block the inner hole. As long as they are not moved, they still somehow work, but after changing the filter (when they are twisted and stretched), they can become unusable in a few minutes. (this is a typical problem with cheap hoses).

It is checked as follows - remove the supply hose from fuel rail and open the lock to the "ignition" position, do not turn on the starter and do not smoke! If a good stream of gasoline comes out of the hose, the reason is not to replace the filter, see what else you did. If the fuel barely runs, check the hoses (according to science, you need to take a pressure gauge and measure the pressure, but I personally don’t have a pressure gauge with an adapter for checking fuel pressure on the farm).

If the filter is composite.

A composite fuel filter with a pressure regulator, used on many "large" foreign cars,. An important feature of these filters is the presence of a built-in fuel pressure regulator. On average, 3% of cheap filters have a defective fuel pressure regulator and after replacing them, the engine does not start.

same problem may be in swollen hoses, but this is only if if the "collective farm" was previously engaged in the repair of the car.

The correctness of the filter replacement is checked in the same way - we remove the feed from the ramp and look at the pressure. (according to science, you need to take a pressure gauge and measure the pressure, but personally I don’t have a pressure gauge with an adapter for checking fuel pressure on the farm).

If the filter is installed in the fuel module in the tank.

Fuel modules cost 90% modern cars. The fuel module is an assembly of a pump, fuel filters, pressure regulator and fuel gauge. Such is the thing in itself.

This is the saddest case because, probably have to take it all apart again. By the way, it is when replacing the filter in the fuel module that most of the jambs come out.

Before disassembling, we check - we remove the feed from the ramp, open the lock and see if the fuel is running and how much it is. (according to science, you need to take a pressure gauge and measure the pressure, but personally I don’t have a pressure gauge with an adapter for checking fuel pressure on the farm).

If the fuel does not run, we remove the fuel module and check where we messed up, there are not many options, here they are:

Everything, everything typical problems because of which, after replacing the fuel filter, the car does not start, I cited. Hope the article was helpful.

Colleagues, that's all for me today. If your car does not start, despite everything, contact the service. By the way, for large cities, an excellent online service at the choice of an auto repair shop.

That's all I have today. If you have any questions, or if you want to supplement the article, write comments.

It happens that drivers have problems after replacing the fuel filter - the car does not start well. The recommendations below will be useful to people who have ruined a car, saving on components.

Bleeding the fuel system

Consider two main options:

On injection and modern diesel units just turn the key to the ignition position, wait a few seconds without turning the starter, then start the car.

If there is a filter with a large volume, the pump does not have time to pump it with fuel, as a result of which the fuel does not enter the engine. In order to prevent this problem, before turning the starter, repeat the procedure from the paragraph above several times, turning the ignition on and off with a delay of three to five seconds. This will allow the fuel pump to prime the system and allow the engine to start normally.

If your car is equipped with an old technology diesel engine, the system is pumped using a pear. Although if you use this type of engine, you are familiar with all its features. But suddenly you are just getting acquainted with such systems - this advice will come in handy.

External

Basically, on cars where it is applied this system, there are two filter elements. The first, coarse cleaning, is used to remove coarse mechanical impurities. The second, fine cleaning, from the smallest foreign bodies. Better to change them in pairs.

If after all the procedures the car does not start, you should pay attention to the hoses, they are often of poor quality, and when they swell, they are main reason inability to start the engine. Cheap hoses just go bad after being disturbed. The braid that holds them on the outside helps the inner hole to close.

To avoid this situation, it is enough to remove the supply hose from the rack and open the lock to the “ignition” position, the starter does not need to be turned on. If a powerful stream of gasoline flows from the hose, changing the filter has nothing to do with it. With a low fuel flow, it is necessary to check the hoses with a pressure gauge by measuring the pressure.

Composite

A characteristic feature of such elements is the fuel pressure regulator built into the mechanism. It is sometimes defective in cheap counterparts, which is why the car does not start. The same result is given by swollen hoses, the problem with which is described in the previous paragraph.

Installed in the fuel tank

In this case, most likely, you will have to disassemble everything, but first you need to check something. It is necessary to remove the feed from the rail, open the lock and make sure that fuel is running and in what quantities. If the fuel does not flow, there are several reasons for the problem:

torn or incorrectly fitted sealing ring;
the fuel hose is not completely put on the pump or filter;
the pressure regulator is not latched;
the electrical terminal is not put on the pump.

Other fuel system malfunctions

Faulty pump

If the new filter is original, has the correct dimensions, and the engine does not start after it is installed, then the hand pump may also be the cause, due to which the system was aired. There are several ways to solve this problem.

Bleed the pump three or more times. If it is serviceable, and the air lock is not located over the entire section of the pipe, everything should work.
In order for the plug to disappear, it is necessary to close the drains of the filtering device and drain a certain amount of fuel using a pear. The system will de-air if fuel flows back. Otherwise, the cause is depressurization.
To obtain excess pressure, it is necessary to remove the hose that is located between the pump and the filter element, supply air to the tank, put the hose back and start the engine. With the remaining problem, it would be advisable to think about changing nodes.

Other reasons

An improperly assembled filter is also the cause of start-up problems. It is necessary to verify the integrity and evenness of the seals.
If the injectors are connected incorrectly, you need to switch the wires.
You should also pay attention to candles. There is a possibility of incorrect installation. You can check this by rearranging the coils, simultaneously checking their integrity. In addition, black soot, the appearance of which is associated with incomplete combustion of fuel, may be the culprit, as well as incorrect work car fuel system.
Wrong location camshafts rare, but can be a source of problems.
It is possible to cause a malfunction with poor quality fuel. Do not neglect this.
Some fuel filters have plugs by default: they are small and made of transparent plastic, so they are hard to see. Starting the engine will be completely absent if they are not removed.