Volkswagen Workshop Service and Repair Manuals

The fuel pressure regulator controls the fuel pressure dependent upon intake manifold pressure.

• ● Fuel pump delivery rate OK, checking:

=> Rep. Gr. 20; Removing and installing parts of fuel system; checking fuel pump

Note:

To prevent fuel spray when loosening connections wrap a cloth around the connection.

• ‒ Connect pressure gauge V.A.G 1318:

▸07.93

• ‒ → Pull fuel pipe -1- off connection -2- on cold start valve.
• ‒ Connect pressure gauge V.A.G 1318 with adapter 1318/10 to fuel pipe -1-.

08.93 ▸

• ‒ → Remove plug -1- on fuel manifold and connect pressure gauge V.A.G 1318 with adapter V.A.G 1318/1 to fuel manifold.
• ‒ Start engine and run at idling speed.
• ‒ Check fuel pressure.
       Specification: Approx. 2.5 bar

• ‒ → Pull vacuum hose off fuel pressure regulator at junction piece -arrow-. The fuel pressure must rise to
       approx. 3.0 bar.
• ‒ Switch off ignition
• ‒ Check for leaks and holding pressure by watching pressure drop on gauge. After 10 minutes there must be
       a residual pressure of
  at least 2 bar.

If the holding pressure drops below 2 bar:

• ‒ Start engine and run at idling speed.
• ‒ After the pressure has built-up switch off ignition and at the same time clamp-off the return pipe -with blue markings- on fuel manifold.
• ‒ Watch pressure drop on gauge.

If the pressure does not drop:

• ‒ Renew fuel pressure regulator.

If the pressure drops again:

• ‒ Check fuel pump non-return valve.

=> Rep. Gr. 20; Removing and installing parts of fuel system; checking fuel pump

• ‒ Check pipe connections, O rings on fuel manifold and injectors for leaks.
• ‒ Check pressure gauge for leaks.

Note:

Before removing the pressure gauge, release fuel pressure by opening the cut-off tap. When doing this hold a container over the connection.