Volkswagen Golf Service & Repair Manual: Checking fuel delivery rate, vehicles with four-wheel drive

Volkswagen Golf Service & Repair Manual / Fuel supply system - Petrol engines / Fuel supply, gas operation / Fuel pump / Checking fuel delivery rate, vehicles with four-wheel drive

Checking fuel delivery rate, vehicles with four-wheel drive

Special tools and workshop equipment required

Removal wedge -3409-

Remote control for V.A.G. 1348 -V.A.G 1348/3A-

Multimeter e.g. hand-held multimeter -V.A.G 1526E-

Test instrument adapter/DSO (5-pin) -VAS 5565-

Pressure tester -VAS 6550-

Vehicle diagnostic tester

Connector cable -VAS 6550/3-3-

Connector cable -VAS 6550/3-4-

Pressure relief valve -VAS 6550/4-

Measuring container, capacity ≥ 3 l

Checking fuel delivery rate, vehicles with four-wheel drive

Auxiliary measuring set -V.A.G 1594C-

Carry out the following work:

Checking fuel delivery rate in engine compartment, quick test:

Note

The fuel delivery rate must first be checked in the engine compartment with the help of the function “Checking fuel delivery rate, quick test”. If the minimum delivery rate is not achieved, a 2nd measurement must be carried out at the flange of the fuel delivery unit.

–	Connect vehicle diagnostic tester.

–	Start Guided Functions.

–	Select the function Checking fuel delivery rate, quick test.

–	Follow instructions on vehicle diagnostic tester.

Checking fuel delivery rate, vehicles with four-wheel drive

If the specification is not attained:

–	Open tank flap unit -2-.

–	Clean area around fuel filler neck.

–	Unscrew cap -1- for fuel filler neck.

–	Check fuel delivery rate, repeat quick test → Anchor.

If specification is attained:

–	Check fuel tank breather → Chapter.

If the specification is not attained:

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

–	Check fuel lines for leaks and damage.

If no fault is found:

Proceed as follows to check fuel delivery rate at fuel delivery unit:

Checking fuel delivery rate at fuel delivery unit:

Note

Separate plug-in connectors → Chapter.

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.

Voltage supply OK → Chapter.

Fuel pressure OK → Chapter.

Battery voltage must be at least 11.5 V. If necessary, connect battery charger → Electrical system; Rep. gr.27.

Fuel pump control unit -J538- OK → Vehicle diagnostic tester.

–	Observe safety precautions → Chapter.

–	Observe rules for cleanliness → Chapter.

–	Connect battery charger → Electrical system; Rep. gr.27.

–	Remove rear bench seat → General body repairs, interior; Rep. gr.72.

Checking fuel delivery rate, vehicles with four-wheel drive

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

Checking fuel delivery rate, vehicles with four-wheel drive

–	Unclip sealing grommet -1- downwards from cover -2-.

–	Push cover -2- back along wiring harness -3-.

Checking fuel delivery rate, vehicles with four-wheel drive

–	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 fuel delivery rate, vehicles with four-wheel drive

–	Check that connector -1- is fitted securely by pulling connector without pressing catch. The connector can cause a fault if it has not been fitted correctly.

–	Release and pull off connector -1-.

–	Check contacts on plug and on fuel delivery unit for damage.

Checking fuel delivery rate, vehicles with four-wheel drive

–	Connect remote control for V.A.G 1348 -V.A.G 1348/3A- with adapter cable -V.A.G 1348/3-3- to contact -1- using an auxiliary cable from auxiliary measuring set -V.A.G 1594C-.

–	Tape off 2nd connector contact of the adapter cable -V.A.G 1348/3-3- with insulating tape -arrow- to prevent short circuits.

–	Connect contact -2- to negative battery terminal -A- using a test lead from auxiliary measuring set -V.A.G 1594C-.

–	Connect remote control -V.A.G 1348/3A- to battery positive terminal clamp -B-.

Note

This step serves only to have the fuel pump running when the engine is stopped.

Checking fuel delivery rate, vehicles with four-wheel drive

–	Pull fuel line -3- 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.

–	The delivery rate of the fuel pump depends on the battery voltage. Therefore connect multimeter to the battery.

–	Connect multimeter with auxiliary measuring set -V.A.G 1594C-.

Checking fuel delivery rate, vehicles with four-wheel drive

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

–	Connect hose -VAS 6550/3-4- to shut-off tap -A-.

–	Connect pressure relief valve -VAS 6550/4- to connection -B- of pressure tester -VAS 6550-

–	Hold end of hose of pressure relief valve -VAS 6550/4- in measuring container.

Checking fuel delivery rate, vehicles with four-wheel drive

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

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

–	Press remote control -V.A.G 1348/3A-.

Note

The fuel system pressurisation pump -G6- will be actuated.

Checking fuel delivery rate, vehicles with four-wheel drive

–	Set pressure of 4.0 bar on pressure relief valve-arrow- using adjuster wheel.

–	Keep the adjuster wheel in this position from this point on.

–	Drain measuring container.

–	Press remote control for 60 seconds whilst measuring voltage at fuel pump.

Checking fuel delivery rate, vehicles with four-wheel drive

–	Compare delivered quantity of fuel with specification indicated in chart.

Checking fuel delivery rate, vehicles with four-wheel drive

Name of axis	Unit
Minimum delivery rate	cm³
Voltage at fuel pump with engine not running and pump running.	Volt

Example:

During the test a voltage of 10.5 volts is measured. This equates to a minimum delivery rate of approx. 1,200 cm³ in 60 seconds.

If specification is attained:

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

–	Check fuel lines for leaks and damage.

If the specification is not attained:

–	Remove fuel delivery unit → Chapter.

–	Check filter strainer for soiling.

–	Check that all fuel delivery unit -1- hose connections -arrows- are connected.

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

–	Check fuel lines for leaks and damage.

If no fault is detected:

–	Renew fuel delivery unit → Chapter.

Checking fuel delivery rate, vehicles with four-wheel drive

Checking fuel delivery rate, engine code CWVA

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