Fuel Pump

A fuel pump is an essential piece of equipment which helps carry fuel from the tank to the device on the vehicle that regulates the fuel/air mixture. It generally comes accompanied by a fuel filter which helps eliminate any pollutants that can be stuck in your fuel lines, fuel tank, or pump itself. The capacity of a fuel pump is measured in psi meaning pounds per square inch. The two most common fuel pump types used on vehicles are mechanical fuel pumps and electric fuel pumps.

Mechanical Fuel Pump:

A mechanical fuel pump is mainly used on engines which rely on a carburetor to deliver the air/fuel mixture into the combustion chambers. They are mainly used on older model engines from the 1950's to the 1980's as they only used from 5psi to 15 psi. A mechanical fuel pump is a low pressure pump generally located bolted directly on the engine block or the cylinder head (varies per engine).

This style fuel pump has a lever on the pump that actuates by riding on the eccentric lobe on the camshaft. The movement of the lever builds vacuum which helps draw the fuel from the tank and into the feed line for the carburetor. The flow of the fuel is controlled by a check valve which ensures that it only flows in one direction.

Electric Fuel Pump:

An electric fuel pump is used on newer engines which rely on fuel injection to deliver the air/fuel mixture into the combustion chamber. The fuel injection system requires fuel pumps which can push out up to 60 psi (varies amongst engines) from the fuel tank into the lines up to the engine. An electric fuel pump is generally mounted in the tank but can be mounted on the outside of the tank as well. The electric fuel pumps helps take an accessory load off the engine and helps reduce the amount of fuel that is being consumed. Most vehicles come with two fuel pump one being a low pressure pump and the other being a high pressure pump.

Electric fuel pumps are mostly ran off an ECU or PCM which help regulate when the pump shuts off and when it comes on. The power train control module looks for a signal from the camshaft so that the relay is charged and it sends a signal to the fuel pump which will help pressurize the system.

Common Issues when fuel pump goes bad

A bad fuel pump can cause stressful issues including poor fuel economy, loss of acceleration, and hard/ no starting. Advancements in the fuel pump have made vehicles more environment friendly, while pushing out the same performance. The benefits of the pump have allowed for the consumer to enjoy a vehicle that is only getting better.