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Home >> Volkswagen >> 2004 >> Jetta Sedan (9M2) L4-2.0L (BBW) >> Repair and Diagnosis >> Powertrain Management >> Computers and Control Systems >> Testing and Inspection >> Component Tests and General Diagnostics >> Fuel Pump, Checking >> Fuel Pump, Checking - II

Fuel Pump, Checking - II



Fuel Pump, Checking

Engine Code BBW

Special tools and equipment







- 3217 Union nut spanner
- V.A.G 1318 Pressure gauge
- V.A.G 1318/11 Adapter
- V.A.G 1318/16 Hose adapter
- V.A.G 1318/17 Adapter
- V.A.G 1318/23 Adapter
- V.A.G 1318/1 Adapter







- V.A.G 1332 Torque wrench (40 TO 200 Nm)
- V.A.G 1348/3A Remote control with adapter cable
- V.A.G 1348/3-2
- V.A.G 1466 A Test system
- V.A.G 1527 B Diode test lamp
- V.A.G 1594 A Adapter set
- V.A.G 1715 or Fluke 83 Multimeter
- Measuring container
- Wiring diagram

Requirements







- Fuse No. 28 OK.
- Battery voltage must be at least 11.5 V.
- All electrical consumers, e.g. lights and rear window defroster, must be switched off.
- If the vehicle is equipped with air conditioning, this must be switched off.
- On models with an automatic transmission the selector lever must be in position "P" or "N".

NOTE: Observe description of crash fuel shut-off function.

Checking function and voltage supply
- Remove cover from fuel delivery unit.
- Briefly operate starter.
Fuel pump must be heard to run
- Switch off ignition.
If the fuel pump does not run:
- Remove cover in front of fuse holder.







- Pull fuse No. 28 out of fuse holder.
- Connect remote control V.A.G 1348/3A with adapter cable V.A.G 1348/3-2 to contact 28a to fuel pump and battery positive (+).
- Operate remote control.

Fuel pump runs:
- Check activation of fuel pump relay referring to wiring diagram:

Fuel pump does not run:







- Take 4-pin connector -1- off flange -3-.







- Connect diode test lamp V.A.G 1527 B with auxiliary cables from V.A.G 1594 A to outer contacts of connector.

- Operate remote control.
LED must light up

If LED does not light up:
- Locate and eliminate open circuit using current wiring diagram:
- Electrical Wiring Diagrams, Troubleshooting & Component Locations
LED lights up (voltage supply OK.):







- Remove flange.
- Check electrical wiring between flange and fuel pump for continuity.

If no open circuit can be found.
- Fuel pump is faulty, replace fuel delivery unit.

Checking Delivery Rate

Requirements
- Voltage supply OK.
- Remote control V.A.G 1348/3A connected.

Work Sequence
- Remove filler cap from fuel tank filler neck.

WARNING:
- The fuel system is under pressure. Before opening the system place a cloth around the connection. Then release the pressure by carefully loosening the connection.
- Always wear eye protection and wear fuel-resistant gloves when disconnecting system connections.







- Pull off supply line -1- and collect leaking fuel with a cloth.

NOTE: To do this slide safety ring -2- into the union -1-.







- Connect pressure gauge V.A.G 1318 with adapter V.A.G 1318/23 and V.A.G 1318/17 to fuel supply line.
- Push hose adapter V.A.G 1318/16 onto adapter V.A.G 1318/11 on pressure gauge and hold hose in a measuring container.
- Open shut-off tap on pressure gauge. Lever then points in direction of flow -A-.
- Operate remote control V.A.G 1348/3A. Then close shut-off tap slowly until pressure gauge shows 3.5 bar pressure. From this point on do not alter setting of shut-off tap.
- Empty measuring container.
- Quantity of fuel delivered by fuel pump depends on battery voltage. Therefore connect multimeter to vehicle battery using adapter cables from V.A.G 1594 A.
- Operate remote control for 30 seconds and measure battery voltage.







- Compare quantity of fuel delivered with nominal value.
*) Minimum delivery cu.cm/30 seconds
**) Voltage at fuel pump with engine at rest and pump running (approx. 2 volts less than battery voltage).

Example:
During the test, a voltage of 12.0 volts is measured at the battery. As the voltage at the pump is approx. 2 volts less than the battery voltage, the result is a minimum delivery of approx. 500 cu.cm/30 seconds.

If the minimum delivery rate is not attained.
- Check fuel pressure regulator. Fuel Pressure Regulator and Holding Pressure, Checking

Fuel pressure regulator is OK
- Check supply line to fuel tank for possible constrictions (kinks).

If supply line is OK.
- Check fuel delivery rate before fuel filter.







- Pull supply line -1- off fuel filter inlet.
- Connect pressure gauge V.A.G 1318 with adapter V.A.G 1318/17 as shown.
- Push adapter V.A.G 1318/1 onto adapter V.A.G 1318/11 on pressure gauge and hold hose in a measuring container.

The connector to the suction jet pump must be installed.
- Engage fuel delivery unit.
- Connect fuel pump again to current supply.
- Carefully pour in some fuel.
- Cover flange opening (danger of spray).
- Open shut-off tap on pressure gauge. Lever then points in direction of flow -A-.
- Operate remote control V.A.G 1348/3A. Then close shut-off tap slowly until pressure gauge shows 3.5 bar pressure. From this point on do not alter setting of shut-off tap.
- Empty measuring container.
- Operate remote control again for 30 seconds.







- Compare quantity of fuel delivered with nominal value.
- Minimum delivery cu.cm/30 seconds
- Voltage at fuel pump with engine at rest and pump running (approx. 2 volts less than battery voltage).

NOTE: Due to the operating of the suction jet pump the minimum delivery rate before the fuel filter/pressure regulator is lower.

Example:
During the test, a voltage of 12.0 Volts is measured at the battery. As the voltage at the pump is approx. 2 Volts less than the battery voltage, the result is a minimum delivery of approx. 415 cu.cm/30 seconds.

If the minimum delivery rate is now attained:
- Replace fuel filter.

If the minimum delivery rate is again not attained.
- Remove fuel delivery unit and check the strainer filter for soiling.

Only if you have not detected any faults up to now:
- Replace fuel delivery unit.

If the delivery rate has been attained but a fuel supply system fault is still suspected (e.g. intermittent failure of fuel supply system):
- Check current draw of fuel pump as follows.
- Install fuel delivery unit.







- Connect multimeter V.A.G 1715 to wire (arrow) for contact 1 of 4-pin connector using current pick-up clamp.
- Start engine and run at idling speed.
- Check current draw of fuel pump.

Specification: max. 9 amps

NOTE: If the fuel system malfunction is intermittent, a check during a road test can be performed with the help of a 2nd person.

If the current draw exceeds the specification:
- Fuel pump is faulty, replace fuel delivery unit.

Checking Non-return Valve For Fuel Pump

Requirements
- Remote control V.A.G 1348/3A connected.







- Pull supply line -1- off fuel filter inlet.
- Connect pressure gauge V.A.G 1318 with adapter V.A.G 1318/17 as shown.
- Push adapter V.A.G 1318/1 onto adapter V.A.G 1318/11 on pressure gauge and hold hose in a measuring container.

The connector to the suction jet pump must be installed.
- Engage fuel delivery unit.
- Connect fuel pump again to current supply.
- Carefully pour in some fuel.
- Cover flange opening (danger of spray).
- Close pressure gauge shut-off tap (lever diagonal to direction of flow (position -B-).
- Operate remote control at short intervals, until a pressure of approx. 4 bar has built up.

WARNING: Danger of spray when opening the shut-off-tap; hold container in front of the free connection on the pressure gauge.

- If pressure builds up too high, lower excess pressure by carefully opening shut-off tap.
- Observe pressure drop on gauge.

Over a duration of 30 minutes pressure must not drop below 3.2 bar

If the pressure drops further.
- Check line connections for leaks.

If no wiring fault is detected.
- Fuel pump is faulty, replace fuel delivery unit.
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