Volkswagen Golf Service & Repair Manual: Checking holding pressure
| Special tools and workshop equipment required |
| Pressure tester -VAS 6550- |
| Connector cable -VAS 6550/3-3- |
| Connector cable -VAS 6550/3-4- |
| Vehicle diagnostic tester |
| – |
Observe safety precautions
→ Chapter. |
| – |
Observe rules for cleanliness
→ Chapter. |
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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. |
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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-. |
| – |
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. |
| – |
Check all fuel lines for leaks and damage. |
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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: |
| – |
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: |
| – |
Remove right rear seat
→ General body repairs, interior; Rep. gr.72. |
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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-. |
| – |
Remove rear bench seat
→ General body repairs, interior; Rep. gr.72. |
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| Continuation for all vehicles: |
| – |
Unclip cover -1- for flange at
retaining tabs -arrows-, using
removal wedge -3409-. |
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| – |
Unclip sealing grommet -1-
downwards from cover -2-. |
| – |
Push cover -2- back along
wiring harness -3-. |
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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. |
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| – |
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. |
|
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| – |
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. |
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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. |
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| 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. |
| – |
Pressure retention valve in fuel delivery unit is defective;
renew fuel delivery unit
→ Chapter. |
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Special tools and workshop equipment required
Removal wedge -3409-
Pressure tester -VAS 6550-
Connector cable -VAS 6550/3-3-
...
Special tools and workshop equipment required
Pressure tester -VAS 6550-
Removal wedge -3409-
Connector cable -VAS 6550/3-3-
...
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Checking holding pressure, engine code CWVA
Checking holding pressure, engine code CWVA