How to Bleed a Fuel Line
Sometimes, a certain amount of unwanted air manages to make its way inside the fuel line. As a consequence, the engine is unable to work properly as the air acts very much like a plug, blocking the right amount of fuel from reaching the engine and preventing it from working properly. In certain cases, fuel is prevented from entering the engine altogether.
The reasons why air enters the fuel line are various. The vehicle may have run out of fuel or undergone a fuel filter replacement. The fuel injector nozzle or fuel pump may have needed some form of repair or a complete replacement. It may even be the case that the vehicle was left unused for an extended period of time with very little fuel in the tank. All these cases are liable to introduce air inside the fuel line which will inevitably need to be released. Fortunately, bleeding a fuel line is a very easy task if the proper procedure is followed.
Step 1
The first step involves locating your vehicle’s fuel rail. Identifying it should not be hard as it generally resembles a rail with an entry point for fuel on one side and housings for fuel injectors on the other. The rail’s purpose is simply to bring fuel to the fuel injectors themselves.
Step 2
Once the fuel rail is located, you will need to find theSchrader valvewhich comes with it. The valve is not difficult to identify as it resembles the valves you would expect to find on any tire. In this case, the Schrader valve’s purpose is to release any air trapped inside the fuel line.
Step 3
Depending on the type of Schrader valve the fuel rail is equipped with, you will need either a screwdriver or a wrench to bleed the fuel line. You would do well at this point to prepare a clean rag which can later be disposed of.
Step 4
If the Schrader valve requires you to depress its centre, do so with the screwdriver. If, on the other hand, it needs loosening, use the wrench. Air should start coming out from the valve at this point, an unmistakable hissing sound marking its exit. The rag should come in handy now as the air will most probably cause fuel to start spewing from the fuel line. Use the rag to prevent the fuel from spraying all over the engine.
Step 5
Once the hissing sound stops, you will need to close the Schrader valve again and re-pressurize the fuel line if it is to start delivering the correct amount of fuel to the engine once more. With the Schrader valve closed, turn on the ignition, stopping one turn short of starting the engine. You should hear the fuel pump readying the entire fuel system for ignition.
Step 6
The moment the sound dies down, turn off the ignition and turn it on once again. Allow the fuel pump to prepare the fuel system once more and turn the ignition off again the moment the pump is done with its task. Repeat the process for the third time.
Step 7
After the process of turning the fuel pump on and off is completed for the third time, you will need to bleed the fuel line once more. Re-open the Schrader valve, allow any air present in the fuel line to emerge (you will need to use the rag again to prevent fuel from spewing all over the engine) and close the Schrader valve.
Step 8
The fuel line will now need to be re-pressurized again. Turn the ignition on once more, let the fuel pump ready the fuel system again and turn the ignition off. Repeat this process twice more.
Step 9
The fuel line’s bleeding should now be complete. However, to ensure no air remains in the fuel line, it is recommended you repeat the entire bleeding and re-pressurizing process for the third and final time.
And that is how you successfully bleed a fuel line.
