Checking Fuel Pressure - Engine Idling

Tools

Fig 1: Identifying Fuel Pressure Tool

Courtesy of PORSCHE CARS NORTH AMERICA, INC.

1. Open the retaining clip for the fuel lines on the underbody and unclip the supply line.
   1. 1.1. To do this, open the clip using a small screwdriver.
      Fig 2: Opening Retaining Clip On Fuel Lines

      Courtesy of PORSCHE CARS NORTH AMERICA, INC.
2. Open the rapid-action coupling on the fuel pressure line.
   1. 2.1. Wrap a cloth around the connection point (to prevent splashes), press the two locking lugs and pull the line apart.

      Alternatively, relieve the fuel pressure. To do this, remove the fuse for the fuel pump, start the engine and leave it running until it stops.

      Fig 3: Identifying Rapid-Action Coupling On Fuel Pressure Line

      Courtesy of PORSCHE CARS NORTH AMERICA, INC.
3. Connect special tool test pressure gauge with lines from K-Jetronic Tester VAG. 1318 WE 1291  to the fuel line.
   1. 3.1. Engage pressure gauge on the transmission bracket using the chain.
   2. 3.2. Insert connection lines into the relevant couplings.
      1. Pressure gauge
      2. Connection line no. 17 from VAG 1318 and P 378 C fitted on line to the engine
      3. Connection line no. 17 from VAG 1318 fitted on line to the fuel tank
         Fig 4: Connecting Special Tool Test Pressure Gauge

         Courtesy of PORSCHE CARS NORTH AMERICA, INC.
4. Start the engine and read off the fuel pressure on the pressure gauge.

   → Fuel pressure - engine idling: 5.0 bar+/-0.3 bar 

5. Switch off the engine after reading the fuel pressure.
6. Holding pressure test (if required): 

   → Pressure: 4.0 bar 

7. Disconnect test connections and remove test pressure gauge.
   1. 7.1. Connect plug-in coupling for fuel lines.
   2. 7.2. The coupling must lock with an audible click. Pull to check that the connection is secure.