General Repair Information
WARNING: This page is about a different car, the 2016 Audi A7 Quattro. However, it is still accessible from the selected car via links, so may be relevant.
CAUTION:
Follow the points below to avoid running the high pressure pump dry (very low tolerances) and to start the engine quickly after replacing the components:
- If fuel system components between the fuel tank and high pressure fuel pump are removed or replaced, then the fuel system must be filled/bled before the first engine start. Refer to FUEL SYSTEM, FILLING/BLEEDING .
- Clean the working area and tools before working on the injection system.
- Check the fuel injector and locations for damage and dirt before installing. Make sure the shaft for the fuel injector is clean. Clean the injector shaft with a clean cloth if necessary without damaging it. Do not use any sharp-edged tools.
- If the high pressure lines will not be replaced, mark them when removing. The high pressure lines must be installed again in the same cylinder.
- Be careful not to damage the injector when removing the old copper seal.
- Check all new O-rings for damage before installing. Lubricate the O-rings with assembly oil or engine oil before installing.
- Align the high pressure lines free of tension. First tighten all connections hand-tight and then tighten them again to the tightening specification.
- Never bend the high pressure lines.
- It is permitted to use tools only for tightening and loosening the lines on the entire high pressure system. All other installation or removal procedures must be performed by hand without using any tools.
- Press the fuel return hoses onto the injectors by hand and from the top until it audibly locks onto each injector (when doing this, do not press the release screw). Then press the release screw downward. Check the fuel supply hoses by pulling upward by hand for secure seating and for leaks.
- Do not disassemble the individual Common Rail (CR) components. The complete component must be replaced if there is a malfunction.
- Do not perform any work on the CR system while the engine is running in idle.
- Do not bleed the CR system by loosening any high pressure components after starting the engine.
- All cable ties which are opened or cut open when removing, must be replaced in the same position when installing.
- Fuel hoses in engine compartment must only be secured with spring-type clips. The use of clamp or screw type clips is not permissible.