VW Golf manuals

Volkswagen Golf Service & Repair Manual: Checking holding pressure

Checking holding pressure

Special tools and workshop equipment required
Pressure tester -VAS 6550-
Removal wedge -3409-
Connector cable -VAS 6550/3-3-
Connector cable -VAS 6550/3-4-
Vehicle diagnostic tester

 
–  Observe safety precautions → Chapter.
–  Observe rules for cleanliness → Chapter.
   
–  Pull off supply line -1-. Separate plug-in connectors → Chapter.
The fuel system is pressurised.Risk of injury due to fuel which may spurt out.Wear eye protection.Wear protective gloves.Release pressure: place clean cloth around connection and carefully open connection.
–  Collect escaping fuel with a cleaning cloth.
Fuel pressure OK and pressure tester -VAS 6550- connected. Check fuel pressure → Chapter.
 

Checking holding pressure

–  Connect fuel line from fuel tank to shut-off tap -B- of pressure tester -VAS 6550- by means of hose -VAS 6550/2-.
–  Connect fuel line leading to engine -1- to shut-off tap -A- of pressure tester -VAS 6550- by means of hose -VAS 6550/1-.
Test sequence:
–  Connect vehicle diagnostic tester.
–  Select final control diagnosis for fuel pump in vehicle self-diagnosis program.
  Note
The fuel pump is now actuated to build up fuel pressure.
If the final control diagnosis is to be carried out several times in succession, it may be necessary to start the engine briefly before repeating the final control diagnosis.
–  Read off fuel pressure on pressure gauge.
Specification: ≥ 4.0 bar.
–  End self-diagnosis and switch off ignition.
–  Observe pressure drop on pressure gauge. After 10 minutes, pressure must not drop below 3.0 bar.
If pressure drops:
–  Check all fuel lines for leaks and damage.
 

Checking holding pressure

If no fault is detected:
–  Ensure that drain tap -C- on pressure tester-1- is closed.
–  Shut-off valves -A- and -B- on pressure tester-1- are open.
–  Actuate fuel pump with final control diagnosis to build up fuel pressure.
–  After pressure has built up, close shut-off valve -A- of pressure tester immediately. Lever is then at right angle to direction of flow.
If the pressure now drops (leak on fuel tank side):
Proceed as follows to check residual pressure on fuel delivery unit → Anchor.
If the pressure does not drop now (leak on engine side):
  Note
Search for leak on engine side. Repeat holding pressure check. This time, close shut-off valve -B- to check whether leak actually is on engine side.
–  If there is a leak on engine side, carry out external check of fuel pipes and high-pressure pump for leaks.
If no fault can be determined, check the injectors for leaks:
–  Remove spark plugs.
–  Open shut-off valves -A- and -B-. Actuate fuel pump with final control diagnosis.
–  Check through spark plug holes whether fuel has collected on piston crown due to a leaking injector.
Checking holding pressure on fuel delivery unit:
Golf SV:
–  Remove right rear seat → General body repairs, interior; Rep. gr.72.
 

Checking holding pressure

–  Partially detach cover -1- in floor covering at parting line -arrow-.
–  Do not detach cover completely from floor covering in order to ensure it is reinstalled in the correct installation position.
–  Detach it just enough that the cover can be folded upwards.
–  Fold up cover in -direction of arrow-.
Golf and Golf Estate:
–  Remove rear bench seat → General body repairs, interior; Rep. gr.72.
 

Checking holding pressure

Continuation for all vehicles:
–  Unclip cover -1- for flange at retaining tabs -arrows-, using removal wedge -3409-.
 

Checking holding pressure

–  Unclip sealing grommet -1- downwards from cover -2-.
–  Push cover -2- back along wiring harness -3-.
 

Checking holding pressure

–  Press up tab -2- in -direction of arrow A-; to do so, reach between floor panel and fuel tank with your finger.
–  At the same time, carefully pull fuel pump control unit-1- out of mounting -in direction of arrow B- by grasping hold of wiring harness -3-.
–  Guide fuel pump control unit -J538- out towards interior between fuel tank and floor panel.
–  Place fuel pump control unit -J538- (with connector still connected) to one side.
 

Checking holding pressure

–  Pull fuel line -1- off flange. Separate plug-in connectors → Chapter.
The fuel system is pressurised.Risk of injury due to fuel which may spurt out.Wear eye protection.Wear protective gloves.Release pressure: place clean cloth around connection and carefully open connection.
 

Checking holding pressure

–  Connect pressure tester -VAS 6550- to fuel delivery unit -1- by means of hose -VAS 6550/3-4-.
–  Connect pressure tester -VAS 6550- to fuel line -2- by means of hose -VAS 6550/3-3-.
–  Ensure plug-in connectors are secured properly by pulling.
  N20-11025
–  Ensure that drain tap -C- on pressure tester-1- is closed.
–  Shut-off valves -A- and -B- on pressure tester-1- are open.
–  Actuate fuel pump with final control diagnosis to build up fuel pressure.
–  After pressure has built up, close shut-off tap -B- of pressure tester immediately. Lever is then at right angle to direction of flow.
–  Repeat holding pressure check → Anchor.
If pressure no longer drops:
–  Check fuel line for leaks.
 

Checking holding pressure

If the pressure drops again:
–  Open fuel delivery unit -1- → Chapter.
–  Check that all hose connections -arrows- are connected.
–  Check fuel lines for leaks and damage.
If no fault is found:
–  Pressure retention valve in fuel delivery unit is defective; renew fuel delivery unit → Chapter.
 

Checking holding pressure

Checking holding pressure, engine code CWVA
Special tools and workshop equipment required Removal wedge -3409- Pressure tester -VAS 6550- Connector cable -VAS 6550/3-3- ...

Checking holding pressure, engine code CWVA
Special tools and workshop equipment required Pressure tester -VAS 6550- Removal wedge -3409- Connector cable -VAS 6550/3-3- ...

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