fuel pump AUDI A4 1998 B5 / 1.G AFC Engine Fuel Supply System Components Workshop Manual

20-3

Safety precautions


WARNING!

When removing and installing the fuel pump
or fuel level sensor from a filled or partially
filled fuel tank:

BEFORE beginning repairs, the suction pipe
of an exhaust extraction system must be
located near the fuel tank opening so that
escaping fuel vapors can be immediately
carried away.
If no exhaust extraction system is available,
a radial fan (motor located outside airflow)
with volume of at least 15 m3/hr (9 cfm) may
be used.
Wear fuel-resistant gloves whenever working
with open parts of the fuel system.

Be sure the ignition is switched OFF, when:
Disconnecting fuel injection system wiring
Connecting or disconnecting test equipment
leads

BEFORE cranking the engine at starting RPM
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- Disconnect battery Ground (GND) strap.

- Remove cover for fuel pump module flange
(under luggage compartment trim).

- Disconnect harness connector for fuel level
sensor and fuel pump.
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20-6


Installing
_________________________________________________________
Front-wheel-drive vehicles:
All-wheel-drive vehicles:
_________________________________________________________ - Detach blue return line and feed line.
- Use special tool 3217 to loosen sealing ring.
- Carefully pull flange out and detach.
- Unclip fuel level sensor and remove.
- Installation is in reverse order of removal.
- Fuel level sensor wiring must be routed between return line and fuel
tank housing.
- Fuel level sensor wiring must be routed between line of fuel transfer
pump and fuel tank housing.

- When installing, make sure that arrows are aligned.
Note different alignment arrows for FRONT-wheel-drive and
QUATTRO
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20-7

Fuel pump, removing and installing


Observe safety measures page 20
-3

Pay attention to rules of cleanliness page 20
-2 .
Removing and installing sealing flange and fuel
level sensor page 20
-5

WARNING!

Fire hazard. DO NOT smoke or work near
heaters or have anything in the area that can
ignite fuel!

Removing

Installing
Installation is in reverse order of removal.
Note: - Insert fuel pump wrench 3307 through fuel tank opening and position at
inner part of fuel reservoir housing.
-
Turn inner part of reservoir housing about 15 to left as far as stop and
remove fuel pump along with inner part of reservoir housing.
Moisten the flange seal with fuel before installing.
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20-9

All wheel-drive-vehicles

- Turn hose -7- and wiring harness -5- into position as shown in upper
left of illustration; when installing flange, turn in direction of arrow as
shown at upper right of illustration.
- Compress clamp -3- with pliers VAG 1275.
1 - Reservoir housing
2 - Flange
3 - Clamp
4 - Securing bolt
5 - Wiring
6 - Cable strap
7 - Hose
- Install reservoir housing with flange into fuel tank.
Wiring for fuel level sensor must be routed between fuel transfer
pump line and fuel tank housing.

- Turn flange to left until arrows (QUATTRO) are aligned.
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20-10

Fuel pump, testing


WARNING!

Fire hazard! DO NOT smoke or work near
heaters or have anything in area that can
ignite fuel!

Checking power supply

Battery fully charged
Fuse 28 OK
Test voltage supply to fuse 28 Repair
Manual, 2.8 Liter V-6 OBD II Fuel Injection
and Ignition, Repair Group 24

Fuel supply OK

- Switch ignition on.
Fuel pump must be heard to run briefly.
(Second person will be required for this if
surrounding noise level is too high).
If fuel pump does NOT run:

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- Remove cover for fuel pump module (under
luggage compartment trim, right rear).

- Disconnect harness connector for fuel pump and
fuel level sensor.
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20-11

- Supply voltage to fuel pump using VAG 1551
scan tool and "Output Diagnostic Test Mode"
function 03.

- Connect multimeter between connector terminal 1 (green wire) and
terminal 4 (brown wire) using adapter cables from VW 1594 connector
test kit.
Specified value: approx. battery positive voltage (B+)
- If specified value is obtained, reconnect harness connector.

If wiring is OK:
Checking fuel delivery - Using ohmmeter, check for continuity between connector (outside of
housing), harness connector and fuel pump.
- Replace fuel pump page 20
-7 .
- Install cover for fuel pump module.
Fuse 28 OK Relay in relay position 6 OK
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20-12


- Disconnect fuel return line -1- at engine compartment bulkhead and
hold in measuring container.
- Connect remote control VAG 1348/3A with auxiliary cable VAG 1348/2
to fuse 28, connect positive (+) cable to battery.
- Operate remote control for 15 seconds (hold down button).

Fuel pump check valve, checking
Testing check valve Repair Manual, 2.8 Liter V-6 OBD II Fuel Injection
Ignition, Repair Group 24 - Compare quantity of fuel delivered with specified values for minimum
fuel delivery rate in graph, according to actual voltage at fuel pump.
*) - Minimum fuel delivery rate-fuel volume in cm3 (ml) delivered in15
seconds
**) - Voltage (V) at fuel pump with engine stopped, fuel pump running-
approx. 2 volts less than battery positive voltage (B+)
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