Checking fuel delivery rate, engine codes CUUA, CUUB: VW Golf Cabriolet (CUUA, CUUB, CUVC, CUVE, …)

🧭 Before you start

Switch off the ignition, remove the engine cover panel and the rear bench seat, and connect the pressure tester and regulating valve into the supply line. With the tester running the guided pump function, set 4.5 bar, lock the adjuster wheel position, empty the container and run the delivery test again; the pump runs for 30 seconds. If delivery is low, check the engine-bay lines, then repeat the test at the line under the seat cover. Still short means removing the delivery unit, checking the filter strainer and hoses, and renewing the unit if needed.

Fits: VW Golf Cabriolet (517, 2011–2016)

• Special tools named: VAS 6551
• Renewed: fuel delivery unit

Don't miss

• The pump can run when a door is opened with the battery connected, so expect fuel to escape from opened lines.
• Supply line is under pressure: eye protection and protective clothing before opening the clamp.
• Once the regulating valve is set, do not move the adjuster wheel for the rest of the test.
• Drain tap closed and both shut-off valves open before each measurement.
• Before condemning the pump, check the filter strainer for dirt and that every hose on the unit is connected.

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

🔧 Engine codes this applies to

📋 Procedure

1. ⚠ Bear in mind that the fuel pump can be activated due to opening of a door with the battery connected. Fuel can escape if the system has been opened. — Observe safety precautions .
2. Observe rules for cleanliness .
3. Switch off ignition.
4. Remove engine cover panel 10Engine cover panel; Removing and installing engine cover panel.
5. Fold front right seat forwards as far as possible.

6. Remove rear bench seat General body repairs, interior72Rear seat; Removing and installing bench seat / individual seats.
7. Open clamp (arrow) of fuel supply line (1).
8. ⚠ The fuel line is under pressure.Risk of injury to eyes and skin from fuel.Wear eye protection and protective clothing to avoid eye injuries and skin contact. Before loosening hose connections, wrap a cloth around the connection. Then release pressure by carefully opening the connection point. — Pull fuel supply line (1) off high-pressure pump (2).
9. Fit connection fittingVAS 6551/5-1 in supply line and secure it with clamp.
10. Connect hoseVAS 6551/2 between connection fittingVAS 6551/5-1 and connection point (A) of pressure tester (diesel)VAS 6551.
11. Connect pressure regulator valveVAS 6551/6 to connection (B) of pressure testerVAS 6551.
12. Hold end of hose of pressure regulating valveVAS 6551/6 in measuring container.
13. Switch on pressure testerVAS 6551 by pressing On/Off button.
14. Ensure that drain tap (C) on pressure testerVAS 6551(1) is closed.
15. Shut-off valves (A) and (B) on pressure testerVAS 6551(1) are open.
16. Connect vehicle diagnostic tester.
17. Select guided function 01 Actuating fuel pump.
18. Select function Checking fuel pump delivery pressure/delivery rate.
19. Follow instructions on vehicle diagnostic tester.
20. Adjust pressure to 4.5 bar with pressure regulating valveVAS 6551/6.
21. Set pressure regulating valveVAS 6551/6 to feed pressure using adjuster wheel (arrow).
22. From this point on do not move position of adjuster wheel (arrow).
23. Drain measuring container.
24. Repeat function Checking fuel pump delivery pressure/delivery rate. [Note: The fuel system pressurisation pump G6 is now activated for 30 seconds.]
25. Check quantity delivered in measuring container.
26. Check fuel lines in engine compartment for possible restrictions (kinks), blockages and damages.
27. Check fuel lines in engine compartment for leaks.
28. Pull off supply line (B), and catch escaping fuel with a cloth. Separate plug-in connectors .
29. ⚠ The fuel line is under pressure.Risk of injury to eyes and skin from fuel.Wear eye protection and protective clothing to avoid eye injuries and skin contact. Before loosening hose connections, wrap a cloth around the connection. Then release pressure by carefully opening the connection point. — Connect hoseVAS 6551/2 to fuel supply line from fuel tank.
30. Connect hoseVAS 6551/2 to connection point (A) of pressure tester (diesel)VAS 6551.
31. Connect pressure regulator valveVAS 6551/6 to connection (B) of pressure testerVAS 6551.
32. Hold end of hose of pressure regulating valveVAS 6551/6 in measuring container.
33. Switch on pressure testerVAS 6551 by pressing On/Off button.
34. Ensure that drain tap (C) on pressure testerVAS 6551(1) is closed.
35. Shut-off valves (A) and (B) on pressure testerVAS 6551(1) are open.
36. Repeat function Checking fuel pump delivery pressure/delivery rate.
37. Remove rear bench seat General body repairs, interior72Rear seat; Removing and installing bench seat / individual seats.
38. Unclip cover (1) at retaining tabs (arrows), using removal wedge3409.
39. ⚠ Bear in mind that the fuel pump can be activated due to opening of a door with the battery connected. Fuel can escape if the system has been opened. — Disconnect fuel return line (1) on sealing flange. Separate plug-in connectors .
40. ⚠ The fuel line is under pressure.Risk of injury to eyes and skin from fuel.Wear eye protection and protective clothing to avoid eye injuries and skin contact. Before loosening hose connections, wrap a cloth around the connection. Then release pressure by carefully opening the connection point. — Connect hoseVAS 6551/2 to fuel supply line connection on fuel delivery unit.
41. Connect hoseVAS 6551/2 to connection point (A) of pressure testerVAS 6551.
42. Connect pressure regulator valveVAS 6551/6 to connection (B) of pressure testerVAS 6551.
43. Hold end of hose of pressure regulating valveVAS 6551/6 in measuring container.
44. Switch on pressure testerVAS 6551 by pressing On/Off button.
45. Ensure that drain tap (C) on pressure testerVAS 6551(1) is closed.
46. Shut-off valves (A) and (B) on pressure testerVAS 6551(1) are open.
47. Repeat function Checking fuel pump delivery pressure/delivery rate.
48. Check fuel lines for possible restrictions (kinks), blockages and damages.
49. Check fuel lines for leaks.
50. Remove fuel delivery unit .
51. Check filter strainer for soiling.
52. Check that all hoses are connected (arrows).
53. Renew fuel delivery unit .

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