Bleeding injectors is a vital process for removing air from the fuel system, ensuring proper engine function, especially after activities like changing a fuel filter or if your vehicle runs out of fuel. Air trapped in the fuel lines prevents fuel from reaching the combustion chambers, causing starting issues or rough running.
Here's a straightforward guide on how to bleed injectors based on common practices:
Why Bleed Injectors?
When air enters your diesel fuel system, it creates blockages that stop fuel flow. This often happens after:
- Replacing fuel filters
- Opening fuel lines for repairs
- Running the fuel tank dry
Bleeding forces this air out, allowing fuel to flow correctly to the injectors.
Step-by-Step Guide to Bleeding Injectors
The process involves loosening the fuel lines connected to the injectors to allow trapped air to escape as the fuel system is pressurized.
Step 1: Preparation - Loosen the Injection Lines
- Locate the injection lines where they connect to each injector on top of the engine.
- Loosen the injection lines at the injectors about one turn. This creates a small gap through which air (and eventually fuel) can escape.
- The use of two wrenches will prevent the binding or twisting of the steel lines. Use one wrench to hold the fitting on the injector still while using the second wrench to loosen the line fitting itself. This prevents damage to the lines or fittings.
Step 2: The Bleeding Process - Crank the Engine
- Ensure the vehicle's battery is well-charged, as you will need to crank the engine.
- Turn the ignition to the 'crank' position. Do not allow the engine to start. You are just turning the engine over to operate the fuel pump and push fuel and air through the lines.
- Crank the engine until all air is forced out and fuel is present at the loosened fittings. You will typically see foamy fuel initially as air mixes with it, followed by solid fuel without bubbles.
Step 3: Observe and Tighten
- Watch each loosened fitting. As cranking continues, you should see fuel emerging.
- Once you see a steady stream of bubble-free fuel from a fitting, tighten that injection line connection securely using the two wrenches again (hold the fitting steady while tightening the line).
- Usually, it is enough to bleed just half of the lines at a time. You don't necessarily need to loosen all lines simultaneously. Bleeding half, tightening, and then potentially bleeding the other half (if needed) is a common practice.
Once all the bled lines are tightened, the engine should be ready to start. It may take a few seconds of cranking to build fuel pressure back up, but it should eventually run smoothly as all air has been expelled.
