Back in the days of carburetors and mechanical fuel pumps, changing out the
fuel filter was a simple affair. A sharp knife or scissors, a few hose clamps,
a foot or so of fuel line, and a new fuel filter took care of things for ten
thousand miles or so.
Since mechanical fuel pumps and carburetors only required low fuel pressure to
operate, things were fairly simple. Modern fuel-injection systems have upped
the importance of the fuel filter through an increase in system operating
pressure, and the importance of keeping fuel injectors free of clogs. Hose
clamps and scissors no longer cut it, and have been replaced by banjo
fittings, high-pressure copper gaskets, and a burst-proof containment vessel.
Even though modern fuel-injected four bangers use less fuel than the
carbureted V-8 monsters of yore, the fuel filter must still be changed on a
regular basis to keep the fuel flowing. A clogged fuel filter can stop fuel
from getting where it needs to go. A lack of fuel can cause sluggish engine
performance and even internal engine damage due to a lean condition.
Pump It Up
The reason the fuel filter is a crucial part of the modern fuel system is
because it ensures that no contaminants get into the injectors and cause
problems. The smallest bit of rust, scale, or debris can spell the end of a
fuel injector. The fuel pump starts pumping fuel from the gas tank into the
lines to build the pressure required to keep the injectors spraying the right
amount of fuel into the cylinders from the instant the ignition key is turned.
The fuel pump is either in the tank itself, or in-line with the fuel supply.
The fuel pressure regulator takes what fuel it needs for the fuel injectors,
and returns the rest to the tank. So it goes. Even if the engine is only using
a small amount of fuel, such as when idling away at a stoplight, the volume of
fuel circulating though the system is still great. The fuel filter has to keep
the fuel clean regardless of whether the regulator sends fuel into the engine,
or back into the tank. Thus the fuel filter works hard whether the engine is
purring away at 850 rpm or screaming up mountain roads at full song.
If the fuel filter becomes clogged, then the fuel system and fuel pump cannot
maintain the required pressure and volume to keep up with engine fuel demand.
If the fuel filter becomes plugged, so does the entire system. Replacing the
fuel filter can help restore peak fuel system efficiency and keep a fuel
operating system running properly.
Gasoline contains enough explosive energy to get a vehicle hurtling down the
road at high speed in no time, and this energy must be treated with the utmost
respect and caution. Gasoline is extremely flammable. Before even thinking
about working with gasoline, take steps to insure safety. Disconnect the
battery and cover the posts to prevent sparks from arcing. Do not drop,
strike, toss, or throw tools as sparks may fly and cause ignition. Remove
watches, bracelets, or any other metal objects from hands. Wear safety glasses
and gloves to protect against accidental skin exposure.
A vehicle service manual is the most important and informative tool available.
Consult one before working with fuel and fuel systems. Have fuel-approved
containers ready to catch any fuel that may come from disconnected fuel lines.
Ready a charged fuel-approved fire extinguisher nearby. We cannot stress
enough the importance of safety when working with gasoline. All that being
said, gather the tools and get to work.