Fuel and Residual Pressure before High Pressure Pump, Checking
Fuel and Residual Pressure before High Pressure Pump, Checking
Special tools, testers and auxiliary items required
• Pressure gauge K-Jetronic (V.A.G 1318)
• Pressure gauge adapter (V.A.G 1318/10-12)
• Remote control (V.A.G 1348/3A) with adapter cable (V.A.G 1348/3-3)
• Measuring container, fuel-resistant
Test Conditions
• Battery voltage at least 12.5 V.
• Fuel filter OK.
• Fuel tank at least 1/4 filled.
• Fuel Pump (FP) control module (J538) OK.
• Ignition switched off.
Checking Fuel Pressure
With Front Wheel Drive
- Fold forward right backrest of rear seat, if necessary.
- Remove luggage compartment floor trim.
- Remove cover for locking flange - arrows -.
- Carefully release and disconnect electrical harness connector - arrow - at locking flange.
With All Wheel Drive
- Remove rear seat bench.
- Remove cover for right locking flange - arrows -.
- Carefully release and disconnect electrical harness connector - arrow - at locking flange.
Continuation for All
- Connect remote control (V.A.G 1348/3A) with adapter cable (V.A.G 1348/3-3) with an adapter cable from connector test set (V.A.G 1594C) at terminal - 5 -.
- Cover 2nd connector terminal of adapter cable (V.A.G 1348/3-3) with insulating tape to prevent short circuit - arrow -.
- Route remote control (V.A.G 1348/3A) switch forward in engine compartment.
- Connect alligator clip to ground (GND) point in engine compartment.
- Connect contact - 1 - to battery "+" using a self-made adapter cable.
• For safety reasons, install a fuse - A - in the cable.
- Remove rear engine cover - arrows -.
CAUTION!
• Fuel system is under high pressure! Before opening high pressure components of the fuel injection system, pressure must be relieved to residual pressure => [ High-Pressure Fuel Injection System, Pressure Relief ] Service and Repair.
• Then wrap a clean cloth around the connection and relieve residual pressure by carefully loosening the connection.
- Disconnect fuel line - arrow -.
- Connect fuel inj. pressure gauge-CIS (V.A.G 1318) with adapter (V.A.G 1318/11) and (V.A.G 1318/12) in fuel line.
- Connect assisting hose - arrow - to pressure gauge and hold it in a measuring container.
- Open shut-off valve of pressure gauge. The lever points in direction of flow.
- Bleed fuel system, by briefly pressing remote control.
- Close shut-off valve of pressure gauge. Lever stands perpendicular to direction of flow - arrow -.
- Hold switch of remote control until no more pressure increase is observed on fuel pressure gauge.
• Specified value: approximately 6 bar positive pressure
If specification is not obtained:
- Check delivery quantity of Fuel Pump (FP).
Checking Residual Pressure
- Check for leaks and for residual pressure by observing the pressure loss on the pressure gauge.
• After 10 minutes there must be a residual pressure of at least 3.75 bar.
The holding pressure drops below 3.75 bar:
• Check connection between fuel pressure gauge and fuel line for leaks.
• Check pressure gauge for leaks.
• Check fuel lines and their connections for leaks.
• Replace fuel filter with integrated fuel pressure regulator.
• Replace fuel pump.
Assembly is in reverse order of removal, note the following:
• Before disconnecting pressure gauge, release pressure by opening shut-off valve. Hold a container in front of connection for this.
Tightening Specifications
