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Checking current draw > < Checking residual pressure

Leon Mk2

Testing quantity of fuel delivered
Testing quantity of fuel delivered
Test prerequisites
l  Speedometer must be okay.
l  Remote control for V.A.G 1348 -V.A.G 1348/3A- is connected.
Checking sequence
  Note
When driving characteristic problems occur when the fuel tank is a approx. 1/4 filled, then check fuel delivery rates with approx. 1/4 filled tank or less.
   
–  Pull fuel return line -1- off fuel filter.
  Note
Press in safety ring to release fuel lines.
–  Connect adapter set -V.A.G 1318/17- or auxiliary hose to fuel filter and hold end of adapter in a measuring glass.
–  Operate remote control -V.A.G 1348/3A- for approx. 5 seconds to fill fuel filter.
–  Drain measuring glass.
–  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 -V.A.G 1594C- to both external contacts (with connector attached) of the fuel pump.
–  Operate remote control for 60 seconds and measure voltage.
  N20-0526
–  Compare delivered quantity of fuel with specification.
1)  Minimum delivery cm3/60 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 a voltage of 10.5 volts is measured. At this voltage the pump can produce a minimum delivery rate of 1,000 cm3/60 Secs.
If the minimum delivery rate is not attained:
–  Check supply line to filter for possible restrictions (kinks) or blockages.
If no fault is found:
–  Remove cap from fuel filler neck and repeat check. If fuel delivery rate is now reached, check fuel tank breather.
If reading again does not match specification:
–  Check the flow of fuel at the entry to the fuel filter.
  WARNING
The fuel line is under pressure!
Risk of injury to eyes and skin from fuel.
Use protective goggles and clothing to prevent injuries and contact with the skin. Before releasing the connections on the hoses, place absorbent cloths round the connection. Then release pressure by carefully loosening the connection.
  N20-10678
–  Pull fuel supply line -arrow- off fuel filter.
  N20-10629
–  Connect pressure tester -VAS 6550- to fuel supply line with adapter -VAS 6550/1-. Hold adapter -VAS 6550/2- in a measuring container.
–  Make sure that drain tap is closed and cut-off taps are open.
–  Operate remote control -V.A.G 1348/3A-. Then slowly close shut-off tap -arrow- until a pressure of 4 bar is displayed on pressure gauge. From here on, do not change position of shut-off tap.
–  Empty the measuring container.
–  Repeat delivery rate check.
If the minimum delivery rate is now attained:
–  Replace the fuel filter → Chapter.
If the minimum delivery rate is again not attained:
–  Remove fuel delivery unit and check filter strainer for contamination.
Only when up to now no fault has been detected:
–  Replace fuel delivery unit.
If fuel delivery rate has been attained, but nevertheless you suspect a fuel supply system fault (e.g. intermittent failure of fuel supply system):
–  Check current consumption of fuel pump → Chapter.
  N20-10632

Checking current draw > < Checking residual pressure