When an engine is losing power or refusing to start, the problem may be with the fuel delivery system. The fuel delivery system includes the parts of the vehicle that keep a consistent amount of fuel (or gas) running to the engine. The fuel delivery system includes the gas tank, fuel pump, fuel filter and the fuel relay. The fuel relay is a small square fuse usually located below the hood and in close proximity to the windshield.
Engine Will Not Start
There are a number of things that will keep an engine from starting but there are ways to narrow down the search for the problem. If an engine cranks (makes grinding noises and sounds as though it is about to start) but does not start it indicates the problem is with the fuel delivery system and not with the spark.
Loss of Power
The fuel relay may be suspect if the car seems to lose power while driving. Loss of power is indicated by the car slowing down with no help from the driver. This does not always mean the car will stall. Sometimes a loss of power will seem to self-correct and the vehicle will go on running for a time. However, a loss of power should not be ignored because the next time the car slows it may come to halt, leaving the driver stranded.
The engine may start for a moment or two and then abruptly stop without ever leaving the driveway. This may be due to a lack of continual fuel feed from the gas tank. This indicates a problem with the fuel filter, fuel pump or fuel relay.
A faulty fuel pump relay can cause the car to come to a complete stop while driving. This will not be instant, but it may resemble what happens when a car runs out of gas. The vehicle will gradually slow to a stop and the engine will refuse to come back on for a time.
The fuel pump is located near the rear of the vehicle and it can usually be heard when the engine starts. The sound of the fuel pump will very by make and model of the vehicle. The absence of sound from the fuel pump area may indicate a faulty pump relay.