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Checking fuel pump non-return valve (engine codes CBTA, CBUA, BGP, BGQ) > < Checking current draw

Golf Mk5

Checking fuel pressure regulator and holding pressure (engine codes CBTA, CBUA, BGP, BGQ)
Checking fuel pressure regulator and holding pressure (engine codes CBTA, CBUA, BGP, BGQ)
   
Pressure gauge -VAS 6550-
  Note
t  The fuel pressure regulator regulates the fuel pressure to approx. 4 bar.
t  The fuel pressure regulator is located on the fuel filter. From October 2005, the fuel pressure regulator has been integrated in the fuel filter and cannot be renewed individually.
t  Observe safety precautions → Chapter.
t  Observe rules for cleanliness → Chapter.
  WARNING
Fuel supply line is pressurised. Wear eye protection and protective clothing to avoid possible injury and skin contact. Before loosening fuel lines, wrap a cloth around the connection. Then release pressure by carefully pulling hose off connection.
  W00-10774
–  Disconnect fuel supply line -3- (metal coupling). To release line, press circlip -3- upwards into housing.
  M10-0042
–  Connect pressure tester -VAS 6550- to fuel supply line with adapter -VAS 6550/1- and -VAS 6550/2-.
–  Make sure that drain tap is closed and cut-off taps are open.
–  Start engine and run at idling speed.
  Note
If engine does not start, activate fuel pump with final control diagnosis.
–  Read fuel pressure on pressure gauge.
l  Specification: 3.7…4.2 bar
If fuel pressure is OK, check holding pressure → Anchor.
If the specification is exceeded:
–  Check fuel return line between fuel filter and flange for possible restrictions (kinks) or blockages.
If no fault is found:
–  Fuel pressure regulator defective, renew fuel pressure regulator.
If the specification is not attained:
–  Check fuel lines for possible restrictions (kinks) or blockages.
If no fault is found:
–  Renew fuel pressure regulator.
  Note
From October 2005, the fuel pressure regulator has been integrated in the fuel filter and cannot be renewed individually.
–  Repeat check.
If the specifications are still not attained:
–  Fuel pump defective, renew fuel delivery unit → Chapter.
If the specification is attained, check the holding pressure as follows:
  N20-10628
–  Watch pressure drop on pressure gauge.
l  After 10 minutes, pressure must not drop below 3.0 bar.
If the pressure drops further:
–  Start engine and run at idling speed.
  N20-10628
–  Switch off ignition and close shut-off tap -B- of pressure tester immediately.
If the pressure does not drop now:
Search for leak on engine side. Repeat holding pressure test. This time, close shut-off tap -A- to check whether leak actually is on engine side.
–  Check fuel rail and injectors for leaks.
If the pressure drops again:
(Leak - fuel tank side)
–  Check fuel lines for leaks.
If no fault can be found on the fuel lines:
–  Check fuel pump non-return valve → Chapter.
If no fault is found
–  Renew fuel pressure regulator → Item.
  Note
From October 2005, the fuel pressure regulator has been integrated in the fuel filter and cannot be renewed individually.
–  Bleed fuel system → Rep. gr.23.
  N20-10598

Checking fuel pump non-return valve (engine codes CBTA, CBUA, BGP, BGQ) > < Checking current draw