Running on Empty
Anyone who has used their Fiero for long distance trips knows that the size
of the fuel tank on our Fieros can mean frequent stops for refueling; even
though we are getting fantastic fuel economy. Some Fieros have actually achieved
fuel economy in excess of 40 miles per gallon during highway driving. But even
this outstanding fuel economy only gets you 400 to 450 miles per tank full of
gas�and that's if you run it almost to empty. Despite the inconvenience of
having to stop for fuel on long trips, here are three good reasons not to run
your fuel gauge down to "E".
On our Fieros, the fuel pump, a device that is powered by electricity, is
located in the fuel tank. Like any mechanical/electrical device, the fuel pump
creates heat in the process of delivering fuel from the tank to the engine. The
fuel pump, which is submerged in gasoline, is actually cooled by the gasoline.
Insufficient gas in the tank can allow the pump to overheat, which will
eventually shorten the life of the fuel pump. In hot weather, the cooling
capacity of the gasoline is diminished, making the pump run hotter. The hassle
and expense of replacing the fuel pump is far greater than the inconvenience of
filling up more often.
If you don't think this is such a big deal, consider that the findings of the
Federal investigation of the crash of TWA Flight 800 stated that a fuel pump
that overheated in a fuel tank that was depleted of fuel most likely caused the
explosion. The tank did contain fuel vapors that were highly flammable and due
to the airliner spending an inordinate amount of time on the ground in this
condition because of a delay, the pump overheated and ignited the fuel vapors.
Luckily, the worst that will occur to you and your Fiero is that the pump will
Secondly, as the fuel in the tank is depleted, the pump is more likely to suck
up dirt and debris in the form of sediment that may be in the tank, as well as
moisture that has an opportunity to collect in an emptying tank. These
contaminants are then stopped at the fuel filter, saving your car's engine from
having to deal with them. However a dirty fuel filter creates greater resistance
to the flow of gasoline and makes the fuel pump work harder to pump the same
quantity of fuel. The moisture in sufficient quantity can result in poor
The third reason not to bump up against the "Empty" side of the fuel
gauge is to reduce the risk of running out of gas on the road. So, replenish
your fuel supply often and don't forget to check and replace the fuel filter.
The Haynes Manual states that the fuel filter should be changed every 30,000
miles or 24 months. The actual intervals may vary depending on the driving
conditions you experience.
The procedure for replacing the fuel filter on the four and six cylinder cars is
different. On the 2.5 L engine (engines with throttle body fuel injection), the
fuel pressure must be relieved prior to removing the filter to prevent the
unintended flow or spraying of fuel. This is accomplished by removing the fuse
marked "Fuel Pump" from the fuse block. Start the engine and run it
until it stops, indicating that the fuel supply in the lines is depleted. Engage
the starter again for three seconds to ensure that any remaining pressure in the
fuel lines is dissipated.
The fuel filter on the 2.5L engine is located to the left of the air cleaner
toward the rear of the engine bay. It is a silver gray cylinder held in place by
a black clamp. Loosen the nuts on both ends of the fuel filter first, then
loosen the clamp bolt underneath the filter. Remove the filter and properly
discard it. Install the new filter insuring that the arrow on the filter is
pointing in the direction of fuel flow toward the fuel injection system. Connect
the lines to the new filter finger snug and then tighten the clamp bolt beneath
the filter. Finally, securely tighten the line fittings. Replace the fuse for
the fuel pump. Keep in mind that when you next try to start the engine, it will
need to be cranked longer than usual as the system pressurizes.
On the multi-port fuel injection systems (the 2.8 L V-6), pressure relief of the
system is accomplished by connecting GM fuel gauge (No. J-34730) to the fuel
rail valve. Wrap a shop rag around the fitting to soak up an errant fuel that
may leak out. Install a bleeder hose routed to an approved gasoline collection
container and open the Schrader valve to bleed off fuel system pressure. The
Haynes Manual recommends raising the rear of the vehicle on jack stands and
placing a collection container beneath the fuel filter. The fuel filter is
located on the right side of the engine in front of the engine bay, behind the
left rear tire, underneath the car (below the passenger's seat). Loosen the
fittings on both sides of the filter and allow the fuel to drain out into the
collection container below. Remove the filter clamp bolt and slide the filter
out of the clamp. Install the new filter insuring that the arrow on the filter
is pointing in the direction of fuel flow toward the fuel injection system.
Install the clamp bolt, but do not securely tighten it. Install the fuel line
fittings finger tight and then tighten the clamp bolt. Tighten the fuel line
fittings. Close the Schrader valve and remove the fuel gauge. Cycle the ignition
switch on and off several times in two-second intervals followed by a ten second
interval to pressurize the system. Check for leaks and lower the car.
Keep your Fiero running on�full.