RAM 3500 Truck 2WD V8-5.7L (2008)
Fuel Level Sensor: Description and Operation
Fuel Pump
Description
DESCRIPTION
The electric fuel pump is located inside of the fuel pump module. A 12 volt, permanent magnet, electric motor powers the fuel pump. The electric fuel
pump is not a separate, serviceable component.
Operation
OPERATION
Voltage to operate the electric pump is supplied through the fuel pump relay.
Fuel is drawn in through a filter at the bottom of the module and pushed through the electric motor gearset to the pump outlet.
Check Valve Operation: The bottom section of the fuel pump module contains a one-way check valve to prevent fuel flow back into the tank and to
maintain fuel supply line pressure (engine warm) when pump is not operational. It is also used to keep the fuel supply line full of gasoline when pump is
not operational. After the vehicle has cooled down, fuel pressure may drop to 0 psi (cold fluid contracts), but liquid gasoline will remain in fuel supply
line between the check valve and fuel injectors.Fuel pressure that has dropped to 0 psi on a cooled down vehicle (engine off) is a normal condition.
The electric fuel pump is not a separate, serviceable component.
