Removing and installing high-pressure pipes between distributor housing (function block) and high-pressure pump / fuel rail — AUDI

🧭 Before you start

Fits: Audi A8 D3 (4E, 2002–2010)

• Special tools named: 3150

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• Always read instructions for working on fuel system.Follow these instructions before starting work and while working on the fuel system . — Remove engine cover panel (refer to instructions for removing and installing ).
• Using commercial cleaning solution etc., clean connections of all high-pressure pipes that have to be opened before removing.
• The high-pressure pipes can normally be used again. Before re-installing them in the vehicle, check the taper seats for distortion and cracks.The bore of the pipe must not be distorted, restricted or otherwise damaged.
• Tighten union nuts hand-tight to start with. Make sure that connections are not under tension.
• Then tighten union nuts to specified torque (counterhold at pressure pipe connection).

🔧 Engine codes this applies to

📋 Procedure

1. ⚠ Always read instructions for working on fuel system.Follow these instructions before starting work and while working on the fuel system . — Remove engine cover panel (refer to instructions for removing and installing ).
2. Using commercial cleaning solution etc., clean connections of all high-pressure pipes that have to be opened before removing.
3. Dry all components after cleaning. [Note: High-pressure pipes between fuel rail and injectors must be marked on removal. High-pressure pipes must always be re-installed in the same position.Counterhold at pressure pipe connections when loosening union nuts.Seal off open connections on pipes immediately with suitable caps.]
4. Open union nuts on the relevant high-pressure pipe using socket (14 mm)3150. [Note: The high-pressure pipes can normally be used again. Before re-installing them in the vehicle, check the taper seats for distortion and cracks.The bore of the pipe must not be distorted, restricted or otherwise damaged.]
5. Blow out high-pressure pipes with compressed air before re-installing.

6. Lubricate threads of union nuts with fuel.
7. Tighten union nuts hand-tight to start with. Make sure that connections are not under tension.
8. Then tighten union nuts to specified torque (counterhold at pressure pipe connection).
9. Run engine at moderate speed for several minutes and then switch off.
10. Check the entire fuel system for leaks.
11. After completing the repair, road-test the vehicle over a distance of at least 20 km. Accelerate with full throttle at least once. Then inspect the high-pressure section of the fuel system again for leaks. [Note: If there is any air left in the fuel system, the engine may switch to the backup mode ('emergency running' mode) during the road test. Switch off the engine and erase the fault memory. Then continue the road test.]

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