A fuel filter is used in the fuel feed pipe ahead of the fuel injection system. The fuel filter housing is steel with a quick-connect fitting at the inlet of the fuel filter and a threaded fitting at the outlet of the filter. The threaded fitting is sealed with an O-ring, which is replaceable. The filter element is paper and is designed to trap particles suspended in the fuel that may damage the injection system. The fuel filter on these vehicles is attached to the underbody, in front of the fuel tank. Note that there are no service intervals for in-line fuel filter replacement. Only replace the filter if performance problems or troubleshooting indicates the filter is restricted.
Care is required when working around the fuel feed and return pipes. Many vehicles now use nylon fuel pipes, designed to perform the same job as steel or rubber fuel lines. Nylon pipes are constructed to withstand the maximum fuel system pressure, exposure to fuel additives and changes in temperature. Two sizes are used: 5 / 16 in. I.D. for the fuel return and 3 / 8 in. I.D. for the fuel feed. Nylon fuel pipes are somewhat flexible and can be formed around gradual turns. However, if forced into sharp bends, nylon pipes will kink and restrict fuel flow. In addition, once exposed to fuel, nylon pipes may become stiffer and are more likely to kink if bent too far. Special care should be taken when working on a vehicle with nylon pipes.
Quick-connect type fittings provide a simplified means of installing and connecting fuel system components. Depending on the vehicle model, there are two types of quick-connect fittings, each used at different locations in the fuel system. Each type of quick-connect fitting consists of a unique female connector and a compatible male fuel pipe end. O-rings, located inside the female connector, provide the fuel seal. Integral locking tabs, or fingers, hold the quick-connect fitting together. For addition information on quick-connect fittings and nylon fuel pipes, please see Section 5 of this manual.