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 fail.
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 performance.
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.