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Engine control unit J623 > < Fuel flow: checking

Leon Mk2

Fuel pressure regulator and retention pressure: checking
   
Fuel pressure regulator and retention pressure: checking
Special tools and workshop equipment required
t  Pressure tester -V.A.G 1318-
t  Adaptor -V.A.G 1318/9-
t  Adapter set -V.A.G 1318/17-
t  Double sleeve -V.A.G 1318/23-
t  V.A.G 1348 remote control -V.A.G 1348/3A-

  Note
t  The fuel pressure regulator maintains the fuel pressure at about 4 bar.
t  The fuel pressure regulator can be found 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.
   
–  Pull off supply pipe/hose -3- and collect leaking fuel with a cloth.
  Note
Press in safety ring to release fuel lines.
  A24-0810
–  Connect the pressure gauge -V.A.G 1318- using the adaptor -V.A.G 1318/9- and the adaptor set -V.A.G 1318/17-to the fuel filter -1- and supply line -2-.
–  Open cut-off tap on pressure gauge. The lever then points in the throughflow direction.
–  Purge the fuel system → Chapter.
–  Start engine and run at idling speed.
–  Measure the fuel pressure. Specification: about 4.0 bar.
If specification is not attained:
–  Switch off ignition.
–  Check quantity supplied by fuel pump → Chapter.
–  If fuel pump is OK, replace 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 retention pressure drops below 3 bar:
–  Start engine and run at idling speed.
  N24-10054
–  Switch ignition off after having built up the pressure. At the same time close pressure gauge cut-off tap (lever at right angles to flow direction) -arrow-.
–  Observe pressure drop on gauge (engine side).
If the pressure drops again:
–  Check the seal on the pipe connections, fuel rail O-rings and injectors → Chapter.
–  Check pressure gauge for leaks.
  Note
Before removing pressure gauge 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 → Chapter.
–  If pressure retention valve is OK, renew fuel pressure regulator → Item.
–  Purge the fuel system → Chapter.
  N24-0618

Engine control unit J623 > < Fuel flow: checking