Fuel pump circuit: mechanical, electric

Gasoline pump - an element of the fuel system of a car that supplies fuel to the dosing system (carburetor / nozzle). the need for such a part in the fuel system appears through the technical arrangement of the internal combustion engine and the gas tank relative to each other. One of two types of fuel pumps are installed in cars: mechanical, electric.

Mechanical are used in carburetor machines (fuel supply under low pressure).

Electric - in injection-type cars (fuel is supplied under high pressure).

Mechanical fuel pump

The drive lever of a mechanical fuel pump constantly moves up and down, but moves the diaphragm down only when it is necessary to fill the pump chamber. The return spring pushes the diaphragm back up to supply fuel to the carburetor.

An example of a mechanical fuel pump

Mechanical fuel pump device:

• camera;
• inlet, outlet valve;
• diaphragm;
• returnable spring;
• drive lever;
• cam;
• camshaft.

Electric fuel pump

The electric fuel pump is equipped with a similar mechanism: it works due to the core, which is drawn into the solenoid valve until the contacts open, turning off the electric current.

An example of an electric fuel pump

What is included in the electric fuel pump device:

• camera;
• inlet, outlet valve;
• diaphragm;
• returnable spring;
• solenoid valve;
• core;
• contacts.

Principle of operation of the fuel pump

It is driven by a diaphragm that goes up and down, since a vacuum is created above the diaphragm (when moving down), the suction valve opens through which gasoline flows through the filter into the supra-diaphragmatic recess. When the diaphragm moves back (up), when pressure is created, it closes the suction valve, and opens the discharge valve, which contributes to the movement of gasoline through the system.

Major breakdowns of the fuel pump

Basically, the fuel pump fails for 2 reasons:

• dirty fuel filter;
• driving on an empty tank.

In both the first and second cases, the fuel pump runs to the limit, and this contributes to the rapid expiration of the provided resource. in order to independently diagnose and find out the cause of the fuel pump failure, read the article on the verification steps.

Checking the fuel pump

You can check the operation of the fuel pump in 5 or 7 stages. To do this, you need to first start with the fuse and end with checking the pressure. Having a multimeter, pressure gauge and battery with wiring Read more