Fuel Pressure and Residual Pressure Before High Pressure Pump, Checking
Fuel Pressure 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)
• Connector Test Set (V.A.G 1594C)
• Remote Control (V.A.G 1348/3A) with adapter cable (V.A.G 1348/3-3)
• Measuring container, fuel-resistant
• Protective gloves
Fuel Pressure, Checking:
• Battery voltage at least 12.5 Volts.
• Fuel filter OK.
• Fuel tank at least 1/4 filled.
• Fuel Pump (FP) Control Module (J538) OK
• Ignition switched off.
- Remove rear seat bench.
- Remove the locking flange cover - arrows -.
- Disconnect electrical harness connector - 1 - at locking flange.
• Ignore - 2 -.
- Connect the Remote Control (V.A.G 1348/3A) with adapter cable (V.A.G 1348/3-3) with an adapter cable from the Connector Test Set (V.A.G 1594C) at terminal - 1 -.
- Cover 2nd connector terminal of Adapter Cable (V.A.G 1348/3-3) with insulating tape to prevent short circuit - arrow -.
- Connect terminal - 5 - to the vehicle ground using a jumper cable from the Connector Test Set (V.A.G 1594C).
- Route Remote Control (V.A.G 1348/3A) switch forward in engine compartment.
- Connect the Remote Control (V.A.G 1348/3A) to item - A - in the terminal box in the plenum chamber (battery +). For safety reasons, install a fuse (10 A) in the wiring connection.
- Remove fuel filler cap from fuel filler tube.
- Remove engine cover.
• Before opening high pressure components of the fuel injection system, pressure must be relieved to residual pressure. Refer to => [ Before Opening High Pressure Fuel Injection System ] Service and Repair.
• Then wrap a clean rag around the connection and relieve residual pressure by carefully loosening the connection.
Disconnect the Fuel Supply Line - arrow - at the Distribution Pipe on Engines with Magnesium Intake Manifolds.
Disconnect the Fuel Supply Line - arrow - at the Distribution Pipe on Engines with Plastic Intake Manifolds.
- Connect Fuel Inj. Pressure Gauge-CIS (V.A.G 1318) with adapter and Adapter Set (V.A.G 1318/10-12) in fuel line.
- Connect an assisting hose - arrow - to pressure gauge and hold it in a measuring container.
- Open shut-off valve of pressure gauge.
• The lever points in the flow direction.
- Bleed fuel system by pressing remote control briefly.
- Close shut-off valve of pressure gauge.
• Lever stands perpendicular to direction of flow - arrow -.
- Hold the switch of the remote control until no more pressure increase is observed on the fuel pressure gauge.
• Specified value: approximately 5.5 bar (4.5 to 6.5 bar) positive pressure
If the specification is not obtained:
- Check the fuel pump delivery quantity.
Checking residual pressure:
- Check for leaks and residual pressure by observing pressure drop on pressure gauge.
• After 10 minutes there must be a residual pressure of at least 3 bar.
If the residual pressure drops below 3 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.
• Check the fuel pump delivery quantity.
• Replace the fuel filter with the integrated fuel pressure regulator.
• Fuel pump check-valve is faulty.
Assembly is in reverse order of removal, note the following:
- Switch off ignition.
• Before removing pressure gauge, release fuel pressure by opening shut-off valve. Hold a container under the connection.
- Install the fuel supply line on the distribution piece. Make sure it is clean and there are no leaks.
Tightening Specifications
