Injector removal & installation: Check pressure retention valve in fuel return line — AUDI

🧭 Before you start

Fits: VW Transporter T6 (7F), VW Transporter T6 (7E)

• Timing position: the crankshaft or camshaft is set and locked during this job
• Special tools named: locking pin
• Renewed: damaged fuel return lines, damaged o-rings

Don't miss

• Ensure cleanliness. No dirt must be allowed to get into the disconnected fuel return lines or the open connections of the injector.
• The pressure retention valve may only be renewed completely together with the fuel return lines.Carry out the measurement close to the pressure retention valve in the fuel return line of cylinder 4.

🔧 Engine codes this applies to

📐 16 workshop diagrams for BJJ

Real factory drawings for this job — timing marks, bolt locations and routing. Locked in the free view.

📋 Procedure

1. ⚠ The engine must not be started with the pressure retention valve removed as the injectors will otherwise be damaged. — Clean all return line connections of number 1 cylinder with, for example, commercially available degreaser before removing them.
2. Dry return line connection of number 1 cylinder.
3. Cover return line connection of number 1 cylinder with a cleaning cloth.
4. Pull return line connection off number 1 cylinder. Pull release pin upwards to do this.
5. ⚠ Carefully pull fuel return lines upwards vertically when disconnecting, as the 4 catches (arrow) can fracture.After disconnecting, check the 4 catches (arrow) to see whether they are fractured or have broken off.Always replace damaged fuel return lines.A damaged fuel return line that becomes loose when engine is running causes damage to injection valve (piezo injector). The injection valve (piezo injector) must then be replaced. — With engine switched off, carefully pull return line connections off injectors. To do this, press both clips downwards (arrow A) and simultaneously pull release pin upwards (arrow B). [Note: Ensure cleanliness. No dirt must be allowed to get into the disconnected fuel return lines or the open connections of the injector.]

6. Fit fuel return system testerVAS 6330 between return line connection on injector and return line.
7. Start engine and run at idling speed for approx. 60 seconds.
8. Check pressure on pressure gauge. [Note: The pressure retention valve may only be renewed completely together with the fuel return lines.Carry out the measurement close to the pressure retention valve in the fuel return line of cylinder 4.]
9. Check O-rings for damage. Replace damaged O-rings.
10. Apply a thin coating of diesel fuel to new O-rings on return-line connections.
11. Attach fuel return line and press the two clips downwards as far as they will go (arrows).
12. After fuel return line has been pushed on completely, press locking pin downwards (arrow).

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