seat Workshop Repair Guides

SEAT Workshop Service and Repair Manuals

Checking intake air system for leaks (unmetered air) > < Checking injectors
Motronic injection and ignition system (4-Cyl.)
Checking components
Checking fuel pressure regulator and holding pressure
 
W24-0009

The fuel pressure regulator regulates the fuel pressure depending on intake manifold pressure.

Special tools, workshop equipment, test and measuring appliances and aux. items required

  • ◆ V.A.G 1318 Pressure gauge
  • ◆ 1318/7 Adapter
  • ◆ 1318/10 Adapter
  • ◆ 1318/13 Adapter
 
N24-0827

→ Connections on fuel rail

The following pipes/hoses are connected to the fuel rail:

  •     1 -    Fuel supply pipe/hose
  •     2 -    Fuel return pipe/hose
  •     3 -    Pipe/hose from activated charcoal filter
Warning!
The fuel supply pipe -1- and the pipe from activated charcoal filter -3- must not be interchanged. Danger of damaging engine!

Test sequence

 
N24-0827
Warning!
Fuel system is under pressure! Before opening the system place a cloth around the connection. Then release pressure by carefully loosening the connection.
  • ‒ → Pull off supply pipe/hose -1- and collect leaking fuel with a cloth.
 
N24-0828
  • ‒ → Connect pressure gauge V.A.G 1318 to fuel supply pipe/hose and to fuel rail using adapters 1318/7, 1318/10 and 1318/13.
  • ‒ Open shut-off tap on pressure gauge. The handle points in direction of flow.
  • ‒ Start the engine and run at idling speed.
  • ‒ Check fuel pressure.
        Specification: Approx. 2.5 bar

 
N24-0829
  • ‒ → Pull the vacuum hose -1- off fuel pressure regulator -2- . The fuel pressure must increase to
        approx. 3.0 bar.

If the specification is not obtained:

  • ‒ Check quantity supplied by fuel pump.

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

If the specification is attained:

  • ‒ Switch off ignition.
  • ‒ Check for leaks and holding pressure by observing pressure drop on gauge. After 10 minutes there must be
        a residual pressure of
    at least 2.0 bar.

If the holding pressure drops below 2 bar:

 
N24-0618
  • ‒ Start the engine and run at idling speed.
  • ‒ → Switch ignition off after the pressure has built-up. At the same time close pressure measured device cut-off tap (handle cross throughflow direction -arrow-).
  • ‒ Observe pressure drop on gauge.

If the pressure does not drop:

  • ‒ Check fuel pump non-return valve.
 
N24-0828

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

If the pressure drops again:

  • ‒ → Open pressure tester V.A.G 1318 shut-off tap (handle in throughflow direction).
  • ‒ Start the engine and run at idling speed.
  • ‒ Switch ignition off after the pressure has built-up. At the same time pinch/seal the return hose together.

If the pressure does not drop:

  • ‒ Renew fuel pressure regulator

If the pressure drops again:

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

Note:

Before removing pressure gauge place a cloth around the connections to be loosened.

Checking intake air system for leaks (unmetered air) > < Checking injectors