Checking restrictor in fuel return line — AUDI

🧭 Before you start

Remove the engine cover, clean and dry the cylinder 1 return line connection, and release it with no dirt entering. Fit the return system tester between injector and line, run the engine and read the pressure. Refit with a new, oiled O-ring until it engages audibly, erase the event memory, bleed the fuel system and check for leaks.

Fits: Audi Q7 (4L, 2005–2015)

Don't miss

• Clean and dry the cylinder 1 return connection before releasing it.
• Keep dirt out of both the open return line and the injector connection.
• Renew the O-ring and lubricate it with engine or assembly oil.
• Push the connector on until the catch engages audibly.
• Erase the event memory, then bleed and leak-check the fuel system.

Written for this job from the workshop steps below · TorqFix editorial.

🔧 Engine codes this applies to

📋 Procedure

1. ⚠ Always read rules for cleanliness and instructions for working on fuel system Follow these instructions and rules for cleanliness before starting work and while working on the fuel system. — Remove engine cover panel.
2. Clean return line connection on cylinder 1 (with commercial cleaning solution or similar) before removing.
3. Dry return line connection on cylinder 1.
4. Cover return line connection on cylinder 1 with a cloth.
5. Detach return line connection from cylinder 1. To do so, press tabs down and pull centre piece up to release connection. [Note: No dirt must be allowed to get into the disconnected return line or the open connection on the injector.]

6. Connect tester for fuel return systemVAS 6330 between return line connection on injector and return line.
7. Start engine.
8. Check pressure indicated on tester.
9. Renew O-ring for return line connection. [Note: Lubricate all seals with engine oil or assembly oil before installing.]
10. Push the return line connection carefully over the new seal and onto the injector. The catch should engage audibly. Then press release pin down carefully.
11. Erase entry stored in event memory using a vehicle diagnostic tester.
12. Bleed fuel system and then check it for leaks.

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