volkswagen Workshop Repair Guides

Volkswagen Workshop Service and Repair Manuals

ABOUT US
Checking current draw > < Checking function and voltage supply

Golf Mk5

Checking fuel delivery rate
Checking fuel delivery rate
l  Voltage supply OK.
l  Fuel pressure regulator and holding pressure OK, checking → Chapter
l  Fuel filter OK.
–  Open cover of relay and fuse holder of E-box in engine compartment.
–  Pull fuse SB6 on socket F6 off hose holder. Fuse assignment → Current flow diagrams, Electrical fault finding and Fitting locations
   
–  Connect remote control -V.A.G 1348/3 A- with adapter cable -V.A.G 1348/3-3- to left terminal (viewed looking forwards) of fuse socket F6 -arrow-.
–  Tape off 2nd connector contact of adapter cable -V.A.G 1348/3-3- with insulating tape to prevent short circuits.
–  Connect crocodile clip to vehicle battery (+).
  Note
t  This step serves only to have the fuel pump running when the engine is stopped.
t  Delivery rate of fuel pump must be measured at 4 bar. Therefore, test fuel pressure before measuring delivery rate.
  WARNING
The fuel system is pressurised! Wear eye protection and protective clothing to avoid possible injury and skin contact. Before loosening hose connections, wrap a cloth around the connection. Then release pressure by carefully pulling hose off connection.
  N24-10235
–  Pull off return line -1- from fuel pressure regulator.
  Note
Press in securing ring to release fuel line.
–  Connect adapter set -VAS 6550/1- to fuel pressure regulator and hold end of adapter in measuring container.
–  Operate remote control -V.A.G 1348/3A- about 5 seconds to fill fuel filter.
–  Empty measuring container.
–  The delivery rate of the fuel pump depends on the voltage. Therefore connect the multimeter to the battery.
–  Operate remote control for 30 seconds while measuring battery voltage.
  N20-10642
–  Compare quantity of fuel delivered with specification.
*) Minimum delivery rate cm³/30 s
**) Voltage at fuel pump with engine not running and pump running (approx. 2 volts less than battery voltage).
Example:
During the test a voltage of 12.5 volts is measured at the battery. Because the voltage at the pump is approx. 2 volts less than the battery voltage, this will equate to a minimum delivery rate of approx. 580 cm³/30 s.
If the specification is not attained:
–  Check supply line to filter for possible restrictions (kinks) or blockages.
If fuel line is OK
–  Remove cap from fuel filler neck and repeat check. If fuel delivery rate is now reached, check fuel tank breather.
If the specifications are still not attained:
–  Check fuel filter (proceed as follows):
  WARNING
Fuel supply line is pressurised. Wear eye protection and protective clothing to avoid possible injury and skin contact. Before loosening hose connections, wrap a cloth around the connection. Then release pressure by carefully pulling hose off connection.
  N20-10138
–  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 -A- until a pressure of 4 bar is displayed on pressure gauge. From this point on do not move position of shut-off tap.
–  Drain measuring container.
–  Repeat delivery rate check.
If the minimum delivery rate is now attained:
–  Renew fuel filter.
If the minimum delivery rate is again not attained
–  Remove fuel delivery unit and check filter strainer for soiling.
Only if still no fault has been detected:
–  Renew fuel delivery unit → Chapter.
–  Reconnect all disconnected fuel lines.
–  Bleed fuel system → Chapter.
If fuel delivery rate has been attained, but nevertheless you suspect a fuel supply system fault (e.g. intermittent failure of fuel supply system):
–  Measure current draw of fuel pump → Chapter.
  N20-10632

Checking current draw > < Checking function and voltage supply