Gasoline pump does not work: possible causes and solutions

2024 Author: Erin Ralphs | [email protected]. Last modified: 2024-02-19 11:41

By itself, gasoline (diesel oil) from a car tank cannot get into the engine, for this you need a pumping mechanism - a fuel pump. And if it fails, the consequences are easy to predict - the car will stop. There can be many possible reasons for this, and since they are typical for almost any car brand, it is better to talk about them using a specific example. Let's assume that the VAZ-2110 fuel pump is not working.

Types of fuel pumps

Serial production of "ten" began in 1995, that is, at a time when domestic cars were equipped with carburetor systems. In them, for pumping fuel, gasoline pumps (pumps) of a mechanical type were installed. Such a pump operates directly from the car engine.

For the correct operation of the carburetor, high pressure is not required, and therefore the pump has a relatively simple design, similar to water pumping systems. It is installed directly under the hood of the car, which certainly facilitates its maintenance or replacement.

With adventof the injectors, the design of the fuel pump was also modified, it became electric. The principle of its work has also changed. If the functioning of the mechanical pump requires the starter to start rotating the crankshaft, then the fuel pump is first powered in the injection system, which, using the built-in electric motor, creates the required pressure in the line, and only after that does the engine start.

This type of fuel pump is installed directly into the fuel tank.

Thus, there are two types of fuel pumps: mechanical and electrical.

Gasoline pump not working: signs of breakdown

Regardless of the design of the engine, if the fuel pump fails, the symptoms of its failure for both types appear the same, and they appear as follows:

1. If the spark plugs are good, the spark is good, the engine turns over, but there are no flashes in the cylinders.
2. Sporadic flashes occur in the engine cylinders, but the engine does not start.
3. Engine starts but revs fluctuate.
4. The engine starts, the idle speed is normal, but when you try to increase it or start moving, the engine stalls.
5. During the movement, the car twitches, when you try to increase the speed, dips in the engine are felt, the dynamics of the car decreases (does not pull).

It is worth noting that similar symptoms can also occur with other breakdowns, for example, with a heavily contaminated fine filter, a faulty MAF (air flow sensor) or cloggednozzles. Therefore, the fuel pump cannot be clearly blamed for these symptoms.

In injection cars, when the ignition is turned on, a buzzing is heard from under the rear seat, this turns on the electric motor that pumps fuel, if there is no sound, then the fuel pump is not working.

Mechanical fuel pump failed: what are the reasons?

There may be several reasons why the VAZ-2110 fuel pump does not work:

• The most common failure is diaphragm damage, since it pumps gasoline, which means it does the bulk of the work, therefore it is most susceptible to wear.
• Faulty fuel pump valves.
• Dirty internal fuel pump strainer.
• Faulty pump drive.

Electric fuel pump does not work, possible causes of failure

In the injection engine, the fuel pump is powered by the car's on-board electrical network, so its failure is not always associated with a breakdown of the pumping mechanism itself. The cause of the malfunction may also be: a failed fuse, relay or oxidation, burning of contacts on the wires that power the electric motor.

Another common reason why the VAZ-injector fuel pump does not work may be a strainer installed at its inlet. Despite the fact that it is intended for the initial, rough cleaning of the fuel, its mesh has a rather dense structure. And since the pump is in the tank, it practically touches its bottomand the sediment that accumulates there, which pollutes it.

Well, the worst thing is the breakdown of the motor responsible for the circulation of gasoline inside the pump or the failure of its structural elements.

Methods for checking the fuel pump

It is very simple to find out if a mechanical fuel pump is working or not, just disconnect the end of the hose connecting the pump to the carburetor, and, lowering it into an empty bottle, press the manual priming lever located on the pump several times. Gasoline should flow out of the hose in a pulsating stream. This will allow you to find out if the internal components of the pump are working or not.

To understand why the fuel pump does not work on an injection engine, you must first "ring out" its electrical circuit. It is better to start the test from the end point, that is, from the pump itself. A control lamp is connected to its terminals, and if it lights up when the key is turned in the ignition, it means that everything is in order with the electrician, the breakdown must be looked for in the pump itself, if not, then in the fuse, relay or in the wiring.

To check the fuel pump itself, you need to find out what pressure it creates in the fuel rail:

• At idle, its value should be within 0.23-0.25 kPa.
• During engine start - 0.3 kPa.
• When pressing the accelerator - 0.28-0.3 kPa.
• When pinching the return pipe that returns excess gasoline to the tank, the pressure should rise to 0.4 kPa.

If in any of the modes the pressure is not normal,therefore, the fuel pump does not work as it should - its elements are badly worn out and require repair or replacement.

Troubleshooting

To repair a mechanical fuel pump, you will need to purchase a repair kit that includes a diaphragm and valves - these parts can be changed independently. Also, it will not be difficult to replace the pusher with a spring. If the breakdown is more serious, then the point in resuscitation disappears, it will be cheaper and easier to install a new fuel pump.

The electric fuel pump has a non-separable body, and you should not try to repair it without certain skills, it is better to entrust such work to specialists. The only thing you can do yourself is to replace the mesh of the internal coarse filter. But here you need to know that the meshes come in different types, so you have to remove the filter from the tank to get a sample.

Fuel pump failure prevention

To extend the life of the fuel pump, you need:

1. Monitor the quality of the fuel refueling in the car.
2. Completely eliminate even the possibility of water getting into the tank.
3. During scheduled maintenance, be sure to change the fuel filters.
4. In case of mechanical damage to the fuel tank, it is necessary to dismantle the fuel pump and check its condition.
5. Periodically clean the fuel tank to remove any buildup of sediment, which consists of the finest solid particles found in gasoline.

Following these simple rules will have a positive effectnot only on the fuel system, but also on the engine itself.