Fuel Pump Delivery Quantity, Checking

Special tools and workshop equipment required

Hand held remote control (jumper).
Electrical connector test lead set.
Fuel pressure test set (high pressure).
Measuring container, fuel-resistant.

Test conditions

Battery voltage 12.5 V.
Fuel filter OK.
Fuse -ST2- OK.

Fuel Pump (FP) Control Module -J538- OK. Refer to Fuel Supply System .
Fuel tank at least ¹ /₄ filled.
Ignition switched off.

Test sequence

-- Remove the rear seat bench Removal and Installation .

-- Remove the screws -arrows- and the right locking flange.

Fig 1: Removing/Installing Cover Bolts For Locking Flange

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-- Disconnect fuel delivery unit electrical harness connector -arrow-.

Fig 2: Disconnecting Electrical Harness Connector At Right Locking Flange

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-- Connect a Hand held remote control (jumper) to terminal -1- of the fuel delivery unit and to vehicle battery (+).

-- Connect a jumper cable from a Electrical connector test lead set to terminal -4- of the fuel delivery unit and to vehicle Ground (GND).

Fig 3: Connecting Jumper Cable From Electrical Connector Test Lead Set To Terminal Of Fuel Delivery Unit And To Vehicle Ground (GND)

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-- Remove the fuel filler cap from the fuel filler tube.

-- Remove the rear engine cover -arrows-.

Fig 4: Removing Engine Covers -1- And -2-

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WARNING:

Fuel system is under pressure! Before opening system, place clean rags around the connection. Then release pressure by carefully loosening the connection.

-- Disconnect the fuel line at the fuel rail -arrow-.

Fig 5: Disconnecting Fuel Line At Fuel Rail

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-- Connect a Fuel pressure test set (high pressure) to the fuel line.

Fig 6: Connecting Fuel Inj. Pressure Gauge-CIS V.A.G 1318 With Adapter V.A.G 1318/11 And V.A.G 1318/12 In Fuel Line

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-- Connect a hose -arrow- to pressure gauge and hold it in the measuring container.

-- Open the shutoff valve of the pressure gauge. The lever points in the direction of flow.

-- Press the switch of the remote control and slowly close the shutoff valve of the pressure gauge.

The fuel pressure should rise.

Specification: 4 BAR positive pressure.

-- Do not move the shutoff valve position.

-- Empty the measuring container.

-- Press the remote control switch in for 15 seconds.

-- Compare the quantity of fuel delivered with the minimum delivery rate in the diagram (cm³ /15s).

Fig 7: Delivery Rate Diagram

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NOTE:

Voltage at fuel pump with engine stopped and pump running is approx. 2 volts less than battery voltage.

If the minimum fuel delivery quantity is not obtained, the following malfunctions may be present:

Fuel lines pinched. Check fuel lines for damage. Repair or replace as necessary. Refer to Fuel Supply System .
Fuel filter clogged. Replace the fuel filter. Refer to Fuel Supply System .
Fuel pump faulty. Check the fuel pump. Refer to Fuel Supply System

Assembly is performed in the reverse order of removal.

-- Install fuel line and tighten the line to 28 Nm.

Torque specifications

Component	Nm
Fuel line to fuel rail	28