Volkswagen Golf Service & Repair Manual: Checking holding pressure

Volkswagen Golf Service & Repair Manual / Fuel supply system - Petrol engines / Fuel supply, gas operation / Fuel pump / Checking holding pressure

Checking holding pressure

Special tools and workshop equipment required

Removal wedge -3409-

Pressure tester -VAS 6550-

Connector cable -VAS 6550/3-3-

Connector cable -VAS 6550/3-4-

Vehicle diagnostic tester

Prerequisites:

Voltage supply OK → Chapter.

–	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.

Checking holding pressure

–	Connect hose -VAS 6550/1- to connection -A- of pressure tester -VAS 6550-.

–	Connect hose -VAS 6550/1- to fuel supply line -1- leading to engine.

–	Connect hose -VAS 6550/2- to connection -B- of pressure tester -VAS 6550-.

–	Use hose -VAS 6550/2- to connect fuel line leading to fuel tank with pressure tester -VAS 6550-.

–	Ensure plug-in connectors are secured properly by pulling.

Checking holding pressure

–	Ensure that drain tap -C- on pressure tester-1- is closed.

–	Shut-off valves -A- and -B- on pressure tester-1- are open.

–	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…7.0 bar.

If fuel pressure is OK, check holding pressure → Chapter.

If the specification is exceeded:

–	Pressure limiting valve in fuel delivery unit is defective.

–	Renew fuel delivery unit → Chapter.

If the specification is not attained:

Proceed as follows to check fuel pressure at 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.

Checking holding pressure

–	Connect pressure tester -VAS 6550- with hose -VAS 6550/3-4- to fuel delivery unit -1-.

–	Connect pressure tester -VAS 6550- and fuel supply line -2- by means of hose -VAS 6550/3-3-.

–	Ensure plug-in connectors are secured properly by pulling.

Checking holding pressure

–	Ensure that drain tap -C- on pressure tester-1- is closed.

–	Shut-off valves -A- and -B- on pressure tester-1- are open.

–	Repeat final control diagnosis to build up fuel pressure.

If specification is attained:

–	Check fuel lines for possible restrictions (kinks) or blockages.

–	Check fuel line for leaks and damage.

Checking holding pressure

If the specification is not attained:

–	Remove fuel delivery unit → Chapter and check for contamination.

–	Check that all hoses are connected -arrows-.

–	Check fuel lines for possible restrictions (kinks) or blockages.

–	Check fuel lines for leaks and damage.

If no fault is found:

–	Fuel pump is defective, renew fuel delivery unit → Chapter.

Checking holding pressure

Checking fuel 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 Removal wedge -3409- Pressure tester -VAS 6550- Connector cable -VAS 6550/3-3- ...

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