Fuel Filter: Description and Operation

DESCRIPTION

The fuel filter has a 5 micron element and was designed for improved high altitude operation. Another design feature is better re-start after the fuel tank has been completely emptied. The water drain and water in fuel (WIF) sensor are located on the top of the filter. Water is drained by using the in-tank electric fuel pump to generate flow (attach a hose to the drain and capture fuel in appropriately marked containers). The filter has a pressure differential of 200-300 mbar (2.9 psi.) when new. When dirty, the pressure differential rises to 800 mbar (11.6 psi.)





The fuel filter is located in the valley of the engine. The filter has the task of cleaning the fuel before it is fed through the fuel supply pump to the high-pressure system and ultimately to the injector nozzles. The filter incorporates the following components:

1. 5 micron fuel filter element.
2. Water separator
3. Water drain valve
4. WIF sensor
Fuel flows from the outside surface to the inside. The fuel filter has a pressure differential of 200-300 mbar (2.9-4.4 psi) when new. When dirty, the pressure differential rises to 800 mbar (11.6 psi). Fuel filtering is critical in common-rail systems. Small amounts of impurities may damage the precision mechanical components over time. Water entering the injection system can also lead to damage.

A water reservoir is located at the bottom of the filter to collect any water contained in the fuel. A drain valve is mounted on the top of the filter housing. The filter should be drained if a Water-in-Fuel message is displayed in the instrument cluster. Water is drained by opening the drain valve and activating the electric fuel pump to generate fuel flow. When draining the filter, attach a hose to the drain valve to avoid spilling fuel.