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Fuel pressure control and retention pressure: checking
Fuel pressure control and retention pressure: checking
Consult the equivalence table for tools and equipment according to applicability between Seat / VW / Audi / Skoda → Chapter.
   
Special tools and workshop equipment required
t  Pressure tester -VAG 1318-, see equivalent → Anchor
t  Valve -VAG 1318/9-, see equivalent → Anchor
t  Adaptor -VAG 1318/17-, see equivalent → Anchor
t  Adaptor -VAG 1318/23-, see equivalent → Anchor
t  Injection quantity tester -VAG 1348-, see equivalent → Anchor

  Note
t  The fuel pressure control maintains the fuel pressure at about 4 bar.
t  The fuel pressure control is installed on the fuel filter.
t  Observe safety precautions → Chapter.
t  Observe rules for cleanliness → Chapter.
  WARNING
Fuel system is under pressure! Wear safety goggles and appropriate clothing to avoid injury and contact with skin. Before loosening hose connections, wrap a cloth around the connection. Then release pressure by carefully pulling hose off connection.
Test requirements
l  Voltage supply for the fuel pump, OK → Chapter.
Test sequence
   
–  Pull off supply pipe/hose -3- and collect leaking fuel with a cloth.
  A24-0810
–  Connect the pressure tester -VAG 1318- using the valve -VAG 1318/9- and the adapter -VAG 1318/17- to the fuel filter -1- and the supply pipe -2-.
–  Open cut-off tap on the pressure tester -VAG 1318-. The lever then points in the throughflow direction.
–  Start engine and run at idling speed.
–  Measure the fuel pressure. Specification: approx. 4.0 bar.
If specification is not attained:
–  Switch off ignition.
–  Check quantity supplied by fuel pump → Chapter.
–  If fuel pump is OK, renew fuel pressure regulator → Item
If the specified value is achieved:
–  Switch off ignition.
–  Check for leaks and retention pressure (complete system). Observe pressure drop on pressure gauge. After 10 minutes there should be a minimum pressure of 3 bar.
If the pressure drops below 3.0 bar:
–  Start engine and run at idling speed.
  N24-10054
–  Switch ignition off after having built up the pressure. At the same time, close the cut-off tap on the pressure tester -VAG 1318- (lever at a right angle to the direction of flow) -arrow-.
–  Observe pressure drop on gauge (engine side).
If the pressure drops again:
–  Check pipe connections, O-rings on fuel distributor and injectors for leaks.
–  Check pressure gauge for leaks.
  Note
Before removing the pressure tester -VAG 1318-, place a cloth around the connections to be loosened.
If the pressure does not drop:
–  Check couplings to fuel tank and pressure retention valve of the fuel pump → Anchor.
–  If pressure check valve is OK, renew the fuel pressure control → Item.
  N24-0618

Engine control unit > < Injection system