Fuel Pump Check Valve, Checking

Fuel Pump Check Valve, Checking

- Remove seat bench.

- Unclip cover - 1 - from fuel delivery unit. Arrow - 2 - points in direction of travel.





- Disconnect 5-pin harness connector from fuel delivery unit.

- Place test instrument adapter/DSO (5-pin) (VAS 5565) on connector and on the fuel delivery unit.





- Connect the remote control (V.A.G 1348/3A) to the test instrument adapter/DSO (5-pin) (VAS 5565 ) and to battery plus (+).

CAUTION!
Fuel supply line is under pressure! Wear protective goggles and protective clothing to prevent injuries and contact with skin. Before loosening the fuel lines, place a rag around the connection point. Then release pressure by carefully pulling hose off connection.

- Disconnect supply line - 1 - from fuel filter input.





• Press in securing ring to disengage the fuel line.

- Connect pressure gauge (V.A.G 1318) to adapter set (V.A.G 1318/17) as shown.

- Connect adapter (V.A.G 1318/1) to adapter (V.A.G 1318/11) of pressure gauge and hold it in a measuring container.

- Close shut-off valve of pressure gauge (V.A.G 1318) (lever perpendicular to direction of flow, position - B -).

- Operate remote control at short intervals, until a pressure of approximately 4 bar has built up.

CAUTION!
Danger of spraying when opening shut-off valve; wear protective goggles and protective clothing to prevent injuries and contact with skin. Hold container in front of free connection of pressure measuring device.

- If pressure builds up too high, lower excess pressure by carefully opening the shut-off tap.

- Watch pressure drop on gauge.

After 10 minutes the pressure must not drop below a 3 bar decrease.

If pressure drops further:

- Check line connections for leaks.

If no fault is detected in the wiring:

- Fuel Pump (FP) faulty, replace fuel delivery unit => [ Fuel Delivery Unit ] Service and Repair.