The petrol pump does not pump gasoline. Possible causes, ways to solve the problem

An automobile gasoline pump is a device intended for the uninterrupted supply of fuel to an installation in which a fuel mixture is formed. Even the slightest of its malfunctions leads to disruptions in the engine, and for more serious problems you simply do not start it.

In this article, we will consider situations where a gasoline pump does not pump fuel at all, or it pumps, but not in the amount that the power unit needs for normal operation. We will also try to understand the possible causes of this or that malfunction of the fuel supply device and discuss methods for their self-elimination based on the example of domestic carburetor VAZ-2109 and VAZ-2114.

What are petrol pumps?

Cars with gasoline engines, depending on the brand, model and modification, can be equipped with various in the design of gasoline pumps. But they all fall into two main categories: mechanical and electrical. Most carburetor engines are equipped with mechanical fuel feeders. If you take VAZ 2109 (carburetor), then from the factory it was equipped with a diaphragm pump manufactured by DAAZ. The main difference of this device is the simplicity of the design, which is easy to understand even for a beginner. In the carburetor "nine" the gasoline pump is located in the engine compartment of the car. It is easy to recognize by the characteristic hemispherical cap and the fuel pipe hoses.

The engines of the VAZ 2114 injector are equipped with electric gasoline pumps. At the heart of their design is also a membrane, but unlike the "mechanics", the fuel supply devices in cars with automatic fuel injection are not located under the hood, but directly in the tank.

Symptoms of a malfunction of the gasoline pump

Whichever engine your vehicle is equipped with, the signs that something is wrong with the fuel supply device are similar. To them it is possible to carry:

1. No engine response to attempts to start.
2. Violation of the stability of the power unit at idle.
3. Tearing.
4. Decrease in power.

The design of the petrol pump of carburetor VAZ 2109

To understand why the petrol pump VAZ 2109 (carburetor) does not pump , let's briefly consider its design. So, the fuel supply device of the "nine" consists of:

• Housing;
• Pusher with mechanical pumping lever;
• Diaphragm assembly;
• Covers with valves and hose fittings;
• The screen filter;
• The manual swap lever.

The operating principle of a mechanical gasoline pump

The gasoline pump is driven by a camshaft cam that moves the pusher horizontally, causing it to reciprocate. The pusher, in turn, acts on the lever of mechanical pumping, and it already raises and lowers the stem of the membrane.

Thus, a certain pressure is created inside the fuel pump , which is supported by the valves of the device cover. One of them passes the fuel inside, not letting it back, and the second pushes into the fuel line, going to the carburetor.

As you can see, the design is very simple, therefore, to determine the reason that the gasoline pump does not pump, it is enough to disassemble it and check the status of the main elements.

Pusher

Since the hull does not affect the operation of the gasoline pump, if it is not damaged, of course, we'll start with the pusher. This element is made of steel and can not just break. But worn - please, especially if it is not original, but bought as a separate spare part. It is worth its length to decrease by several millimeters, and the gasoline pump does not pump fuel.

Rather, it is shaking, but the amplitude of the motion of the diaphragm is significantly reduced. Hence the low fuel pressure in the system, and as a result, the engine malfunctions. The standard length of the pusher for pumps DAAZ - 84 mm. Measure its length, and if necessary, replace the worn out part.

Diaphragm

The most common defect in the diaphragm is its rupture. It also happens that it is deformed. Due to these damages, the diaphragm begins to pass fuel through itself, which also causes a drop in pressure in the system.

It is possible to detect such a malfunction by disassembling the fuel supply unit. If the diaphragm is responsible for the fact that the pump does not pump, you will immediately see it. This problem is solved by replacing it.

Cover with valves and fittings

Since you dismantled the gasoline pump, do not be too lazy to check the valves. One of them must let in the fuel, and the other - let out. Simply purge them and determine how clearly they work. If the valves do not cope with their tasks, replace the lid assembly.

Pump filter and manual pumping lever

The first thing you will see, having disassembled the device of giving of fuel - the mesh filter. It is made of thin perforated plastic. The fault is that the petrol pump does not pump, it can also be used if there is deformation or severe contamination.

In the first case, the filter should be replaced, in the second - flushed with a carburetor cleaning fluid.

The manual swing arm to the fact that the gasoline pump does not pump fuel when the camshaft rotates has nothing to do with it. The only thing that can break in it is the spring that throws it back to its original position.

The petrol pump does not pump: the injector

As already mentioned, pumps in carburetor and injector engines have a different design. In cars with forced fuel injection, all the processes associated with its supply to the combustion chambers are controlled by an electronic control unit, so there may be breakdowns of various kinds of electronic devices.

To the main reasons for which the petrol pump of the injector engine does not pump, you can refer:

• Malfunction of the electric drive of the device;
• Clogging the pump filter;
• Failure of the relay;
• Fuse blown.

How to understand that the cause of power outages is the petrol pump

Diagnosing problems with a petrol pump in a car with an injector engine is much easier than in a car with a carburetor motor. The fact is that when the ignition is switched on, the sound of the electric motor of the fuel module is clearly heard. It lasts a few seconds. This sound indicates that the gasoline pump turns, pumps fuel.

If this happens when the key is rotated, then the device itself is OK, and the cause needs to be looked elsewhere. Well, if you do not hear the characteristic sound of the pump when you turn on the ignition, you can be sure - the problem is in it, or in the elements of its power supply.

Start with a relay and a fuse

Given that the fuel supply module is in the tank of a car, and getting to it is not so simple, it is better to start the diagnosis with a relay and a fuse:

1. Remove the screws securing the cover of the mounting block to the left of the steering column.
2. Under it, find the fuse F3 (15 A) and relay R2. These are the elements that we need to check.
3. As for the fuse, it needs to be "tapped" by the tester. In case of unfitness, replace it.

Check the relay in a garage is quite difficult. But you can take a similar (from a nearby socket), known to be a serviceable relay, and put it instead of the one being diagnosed. Now turn on the ignition. Does the gas pump pump? The reason is found! Well, if nothing has changed, go ahead.

Electric drive and filter

The petrol pump in the injector VAZ 2114 is an element of the fuel module, which is located in the tank of the car. It also includes:

• Coarse filter;
• Fuel level sensor;
• Branch pipes for connection to the fuel line.

To get to the module, it is necessary to remove the lower part of the rear seat, disconnect the wiring harness and unscrew the 8 screws securing its cover. Remove the entire assembly. First, inspect the coarse filter. If it is clogged, replace it.

To test the motor, you must connect it directly to the battery terminals. In case of its normal operation, "ring" the wiring and check the contact of the ground wire on the module cover. If the electric motor does not show signs of life, the question "why does not pump the petrol pump" finally find its solution.

Trying to repair it yourself is impractical. Just buy a new motor and install instead of the old one. And yet, do not spend money on the purchase of the entire module, which now costs about 3 thousand rubles. Buy a separate electric motor and a new filter. All this will cost you three times cheaper.