Volkswagen Workshop Service and Repair Manuals

Note:

The system pressure should only be tested after the fuel delivery rate and the fuel filter have been checked:

=> Repair Group 20

• ● The plugs must be connected to the warm-up valve -N9- and the aux. air valve -N21-.

• ‒ → Connect pressure gauge V.A.G 1318 between fuel meting distributor and control pressure pipe of the warm-up valve. To do this screw the pressure gauge connector into the fuel metering distributor.

• Always use new sealing rings.

• ‒ Close pressure gauge valve (lever at right angles to follow direction -B-).
• ‒ Start engine, run it at idling speed and read off system pressure.

Specifications:

• ‒ → If the reading is not correct, adjust system pressure by changing the adjusting shims -1-.
• ‒ thicker or more shims = -increased pressure-
• ‒ thinner or fewer shims =-lower pressure-

• Pressure change:
• ‒ 0.5 mm shim = approx. 0.3 bar
• ‒ 1.0 mm shim = approx. 0.6 bar

Notes:

• ◆ To reduce pressure, slacken off control pressure pipe at warm-up valve (large connection). Wrap cloth around connection danger of spray.
• ◆ If despite changing the adjustment shim the specification is still not attained, the following faults may be present in the system:

System pressure too low:

Fuel supply pipe kinked, blocked, laking, fuel reservoir leaking, fuel pump delivery rate too low, System pressure regulator/pressure relief valve defective, dirty, fuel metering distributor defective.

System pressure too high:

Fuel return pipe blocked or kinked, system pressure regulator-pressure relief valve defective.