How to Bleed a Fuel Lineby Alibaster Smith
The fuel line carries the fuel from the fuel tank to the fuel injection system in your vehicle. Fuel lines are under high pressure. Whenever you work on them, you'll need to relieve that pressure using something called a Schraeder valve, which is located on the fuel rail in most vehicles. When you are done working on the fuel system, purge the system of air. To do this, you must know how to bleed a fuel line.
Open the hood of your vehicle and locate the fuel rail. This is normally located towards the back of the engine bay, on top of the engine towards the firewall.
Locate the Schraeder valve. This valve looks like a valve stem that you would normally find on a tire. This valve is a bleeder valve that will release pressure and purge air from the system if you loosen or remove it. On some vehicles, you may be able to press down on the valve to release pressure.
Place a rag over the end of the valve, and either loosen the valve with the wrench or depress the center of the valve with the flat head screwdriver. You will hear air coming out of the valve, but you may also notice gasoline spraying out also. The rag is to prevent the gasoline from spraying all over the engine bay.
Re-pressurize the fuel system by shutting the valve and turning the ignition to the "on" position (the position just before the crank position where you attempt to start the vehicle). You will hear the fuel pump prime the system. When the pump stops, turn the ignition off, and turn it back on again, and allow it to pressurize the system again. Repeat this process several times.
Repeat steps 3 and 4 again. This should ensure that your fuel system is properly bled and is working as it should.