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Pressure regulator of the fuel and the holding pressure: check > < check operation and electricity supply

Leon Mk2

Fuel delivery quantity: check
Fuel delivery quantity: check
  Note
t  There are pressure controllers that have different control pressures. In this case, the fuel pressure controller with 3 or 4 bars is used.
t  The fuel pressure regulator is installed on the fuel filter.
t  When replacing the pressure controller, care must be taken to install the pressure controller type specified by the manufacturer → ETKA (Electronic parts catalogue)
Test prerequisites
l  Voltage supply for the fuel pump, OK → Chapter.
l  The fuel pressure regulator and the retention pressure are okay, check the fuel pressure regulator and the retention pressure → Chapter.
Checking sequence
  Note
t  The delivery rate of the fuel pump is measured depending on the operating pressure of the fuel system. This is why you have to check the fuel pressure before measuring the delivery rate.
t  The 3 bar pressure regulator must generate an approx. pressure of 3 bar in the system.
t  The 4 bar pressure regulator must generate an approx. pressure of 4 bar in the system.
–  Remove filler cap from fuel tank filler neck.
   
–  Disconnect the fuel return line -1-. Push the buttons on the fuel hose coupling for this purpose.
  WARNING
Fuel system is under pressure! Before opening the system place a cloth around the connection. Then release pressure by carefully pulling fuel hose from connection. Wear safety goggles and appropriate clothing to avoid injury and contact with skin.
–  Connect adaptor -VAG 1318/17- to pressure tester and place adaptor end in a measuring container.
–  Operate the remote control -VAG 1348/3A- for 5 seconds, to fill the fuel filter.
–  Empty measuring container.
–  The quantity of fuel delivered by the fuel pump is dependent upon voltage. Therefore, connect the multimeter with auxiliary line from the auxiliary measuring set -VAG 1594C- to both external contacts (with connector attached) of the fuel pump.
–  Operate the remote control -VAG 1348/3A- for 30 seconds, and measure fuel pump voltage.
  N20-0526
–  Compare fuel delivery rate to specification.
1)  Minimum delivery cm3/30 s
2)  Voltage on the fuel pump when the engine is stationary and with running pump (approx. 2 volt under battery voltage).
Readout example:
During the test, the fuel pump is measured at 10.5 volts. With this voltage the pump should produce a minimum delivery rate of 540 cm 3/30 s.
If the minimum delivery rate is not attained:
–  Check the fuel pipes to the filter for possible restrictions (kinks) or blockages.
If the fuel line is not damaged:
–  Check the flow of fuel at the entry to the fuel filter.
  WARNING
Fuel system is under pressure! Before opening the system place a cloth around the connection. Then release pressure by carefully pulling fuel hose from connection. Wear safety goggles and appropriate clothing to avoid injury and contact with skin.
  N20-0134
–  Remove the supply line -1- from the fuel filter inlet. Push the buttons on the fuel hose coupling for this purpose.
–  Connect fuel supply pipe to pressure tester -VAG 1318-, using adapter -VAG 1318/17-.
–  Connect adaptor -VAG 1318/11- and adaptor -VAG 1318/1-to pressure tester -VAG 1318- and place adaptor end in a measuring container.
–  Open cut-off tap on pressure gauge -VAG 1318-. The lever then points in through flow direction -A-.
–  Press the remote control -VAG 1348/3A- for approx. 10 seconds in order to fill the fuel filter and to build up the system operating pressure.
The 3 bar pressure regulator must generate an approx. pressure of 3 bar in the system.
The 4 bar pressure regulator must generate an approx. pressure of 4 bar in the system.
–  Empty measuring container.
–  Activate remote control -VAG 1348/3A- for 30 seconds. Compare the flow with the first value measured.
If the minimum delivery rate is now attained:
–  Replace fuel filter.
If the minimum delivery rate is again not attained:
–  Remove the fuel delivery unit and check the strainer filter for soiling → Chapter.
Only when up to now no fault has been detected:
–  Renew fuel delivery unit → Chapter.
If the delivery rate has been attained but nevertheless you suspect a fuel supply system fault (e.g. intermittent failure of fuel supply system):
–  Check the current draw of the fuel pump as follows:
–  Reconnect all disconnected fuel pipes.
  N20-0531
–  Connect the multimeter -VAG 1715- with the crocodile clip to wiring -arrow- that runs to contact 1 of the 4-pin connector.
–  Start engine and run at idling speed.
–  Measure the power consumption of the fuel pump:
t  Specification: 8 Amps maximum
  Note
If there is a temporary fuel system fault, the check can also be carried out during a test drive, with the help of a second person.
If the current draw is exceeded:
–  Fuel pump is defective, renew fuel delivery unit → Chapter.
  N20-0402

Pressure regulator of the fuel and the holding pressure: check > < check operation and electricity supply