Description:
The typical fuel filter for most fuel-injected cars consists of
a high-pressure canister filled with filtering media. Filters may have
clamped, threaded or special fittings to ensure
reliable connection to the
fuel system. Filters for carbureted engines may be located at the inlet of the carburetor or inline. Filters for carbureted engines do not need to withstand the same pressures as those for fuel-injected engines.
Purpose: Fuel filters trap
harmful contaminants that may cause problems with carburetors and
intricate fuel injectors. Fuel filters for carbureted engines only
clean the fuel before it enters the float bowl. Injection filters,
on the other hand, clean the fuel whenever the fuel pump runs
(unless the fuel injection system is a “returnless” design). Fuel
moves continuously up the supply side, through the filter to the
fuel rail or throttle body. The fuel that doesn't make it into the
engine returns to the tank and the whole process starts over again.
With a full tank of gas, the filter may
clean
the volume of fuel in the tank many times before it's
all used.
Maintenance Tips/Suggestions: On carbureted cars, replace the filter
once a year. On cars with fuel injection, some carmakers don't
recommend replacing the filter at all during the first 100,000 miles
of "normal" driving. Since “normal” usually constitutes severe
driving because of less than normal conditions, it's best to replace
the filter every two years or 24,000 miles. A contaminated filter
can restrict fuel flow from your car’s electric fuel pump,
eventually taking a toll on its life. Frequent filter replacements
remove all doubt about whether the filter may cause other problems
down the road. Most filters on domestic cars and trucks hide
underneath on the frame or body. Just the opposite is true on the
imports. They usually
put their filters somewhere in
the engine compartment. If you decide to change the filter yourself,
be careful. Fuel injection systems maintain pressure in the
lines that must be relieved prior to filter replacement. Don’t forget
that gasoline is extremely flammable. Procedures vary for relieving pressure. Also,
some filters require special tools to replace the fuel filter. Because
of these technicalities and because of most
filter locations, it’s best to have your car’s fuel filter
replaced by a qualified service professional.
