AUDI A4 1999 B5 / 1.G Fuel Supply System Biturbo 2.8 Workshop Manual

20-107


Fuel supply system, servicing
(vehicles with 2.7 ltr. turbo
engine) WARNING!
Always comply with all applicable safety
precautions when working on the fuel system
Note:

Always replace gaskets, seals and hose clamps
when working on the fuel system.
Hose connections are secured either with
screw-type or spring-type clamps. Always
replace clamps with factory clamps, see Parts
catalogue.
1 -
Sender for fuel gauge -G
Ball-shaped floatCheck resistance Page 20
-125
Removing and installing Page 20
-128
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2 -
Fuel return line
With Fuel Pump (FP)Attached from the inside to fuel pump
flange To remove depress tab at connector
3 -
Seal ReplaceWhen installing, insert dry into opening of
fuel tank
4 -
O-Rings ReplaceCheck for correct installation
5 -
Fuel return line From fuel distributorMark before disconnectingLook for arrow on fuel pump flange
6 -
Fuel supply line To fuel distributorMark before disconnectingLook for arrow on fuel pump flange
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7 -
Fuel pump flange
Can only be installed together with fuel
pump. Removing and installing Page 20
-118
Installation position: Note arrow Page 20
-123

8 -
Connector
For fuel pump and sender for fuel gauge -G
9 -
Threaded cap nut - 60 Nm
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20-110


Repair Manual, Fuel Injection & Ignition,Repair
Group 24 10 -
Fuel Pump (FP)
With fuel screenCan only be replaced with fuel pump flangeRemoving and installing Page 20
-118
Fuel pump, electrical check Page 20
-
111

Pressure test:
11 -
Fuel accumulator housing, lower part
Part of fuel tankCannot be replaced separately
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20-111


Fuel pump, checking electrically

Vehicles with 2.7 ltr. turbo engine
Special tools needed:

VAG3217
VAG1348/3A with VAG1348/3-2
VAG1526 A
VAG1594 A
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Test conditions:

Battery voltage at least 12 V
Fuse 28 OK

Test sequence
Relay 6 in central electric OK Fuel filter OK Ignition switched off.
- Open cover for fuse panel on left side of instrument panel.
- Remove fuse 28 from fuse panel (left row, fifth large fuse from the top).

- Connect remote switch VAG1348/3A with adapter wire VAG1348/3-2 to
right terminal of fuse socket 28 -arrow-.
- Connect alligator clip to vehicle battery (+).
- Press remote switch button.
Fuel pump must be heard to run.
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20-113

Note:
The fuel pump runs very quietly. Be sure to keep
outside noise low when testing the fuel pump.
If you cannot hear the fuel pump run:

- Remove carpet liner in luggage compartment.

- Unscrew cover fuel pump flange.

- Unclip 4-pin connector and disconnect connector.

- Switch multimeter Fluke 83 to DC voltage range 20 V and using test
wire from VAG1594 A, connect to terminal 1 (green/yellow) and 4
(brown) of connector.
- Press remote switch continuously and read voltage.
Specified value: Approx. battery voltage
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20-114
If specified value was obtained even so you
could not hear the fuel pump run, remove the fuel
pump flange as follows:

WARNING!

Fire hazard! Remove everything from the area
that could ignite fuel or fuel vapor. fuel
system is under pressure. Cover connection
with rag and carefully release pressure by
slowly opening the connection.

- Mark fuel return line -2- and fuel supply line -3- and remove from fuel
pump flange.

- Remove threaded cap nut with wrench 3217.
- Lift flange and seal from tank opening.
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20-115


If wiring and connections are OK: - Check electrical connections between flange and fuel pump, check for
continuity.
- Fuel pump is faulty; replace pump Page 20
-118
.
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20-116

Fuel pump delivery volume, checking


Vehicles with 2.7 ltr. turbo engine

Special tools needed:
Test conditions:
Test sequence
Remote switch VAG1348/3A with adapter wire VAG1348/3-2Measuring cupBattery voltage at least 12 V Fuel filter OK Ignition switched off.
- Open fuse panel cover at left side of instrument panel.
- Remove fuse 28 from fuse panel (left row, fifth. large fuse from the
top).

- Connect remote switch VAG1348/3A with adapter wire VAG1348/3-2 to
right terminal of fuse socket 28 -arrow-.
Pa
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ly system, servicin
g (vehicles with 2.7 ltr. turbo en
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