How Can Mechanical and Electric Fuel Pumps Work

The essential part of any vehicle’s fuel system is fuel pump. Its main purpose is to collect fuel for tank and supply at properly to the engine.  The fuel pumps are in two types – mechanical and electric.

Mechanical fuel pumps were mostly used in older models and electric fuel pumps mostly used at modern models. Now we discuss how they work and how are different form each other.

Mechanical and Electric Fuel Pumps

Mechanical fuel pump

They are work with carburetors in vehicles.  They collect fuel from tank and supply to carburetor. During this process there is less pressure involved. The central component in the pump is a diaphragm that could increase and produce vacuum.

How it works

*Basically there are three components – camshaft, lever arm and diaphragm

*The eccentric lobe which is in the camshaft pushes the lever arm upwards during the camshaft rotates.

*Diaphragm attached to moves down for expand the space and the other end pulls of the lever arm.

* Vacuum created inside the pump and fuel is drawn into the inlet line from the tank and outlet is still closed when space expands.

*After expend the space, Diaphragm pushed back to normal position with attached spring. This will opens up the outlet valve and closes the inlet valve and fuel will go toward the carburetor.

*Carburetor blends the fuel and air to transfer toward the engine.

Electric fuel pump

This is basically electronic fuel injection system used in most modern vehicles. They work more professionally and transport higher pressure (40-60psi). The pump is fitted inside the tank to maintaining proper temperature of the pump.

How it works

*Electric fuel pump and mechanical fuel pump work similarly

* Similar the mechanical fuel pump, the electric also check valve and diaphragm pull system, but diaphragm pull is working by electric switch called ‘solenoid’

* The diaphragm is not directly linked to the solenoid, its linked only to an iron rod. The solenoid uses this iron rod for electromotive force to pulling down the diaphragm and drawing fuel into the chamber

* When this occurs, the solenoid pulls separately the contacts through which electricity passes. This disconnect the power supply and the spring pulls the diaphragm at normal position and fuel drawn the outlet valve

* The outlet valve opens allowing this discharge

* When this occurs, the electrical connectivity is returned and the solenoid again pulling the iron rod