1998 AUDI A4 fuel pressure

20-14


Fuel filler neck, component overview
(vehicles with ORVR)

Vehicles with front wheel drive and 1.8 ltr. turbo
or 2.8 ltr. engine
1 -
Bleed line
To top of filler neck on fuel tank
2 -
Expansion tank Clipped to fuel-filler neck
3 -
Tank ventilation valve Clipped to fuel-filler neckVentilates fuel tank for pressure
compensation
Pa
ge 9 of 49 Fuel su
pp
ly system, servicin
g (vehicles with front wheel drive and 1.8 ltr. turbo or 2.8 ltr. en
gine
)
11/19/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.GE04.20.2

20-21


WARNING!
Fuel system is under pressure! Before opening, place clean cloths
around the connections to be opened. Carefully loosen the
connections to relieve pressure. - If present, remove the aerodynamic trim panel from the rear axle -
arrows-

- Mark and remove the supply line -1- and return line -2- .
On bottom of vehicle
Pa
ge 16 of 49 Fuel su
pp
ly system, servicin
g (vehicles with front wheel drive and 1.8 ltr. turbo or 2.8 ltr. en
gine
)
11/19/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.GE04.20.2

20-29


Repair Manual, Fuel Injection & Ignition, Repair
Group 24 11 -
Nut M4
1.5 Nm
- Install toothed washer beneath
12 -
Nut M5
13 -
Fuel supply unit Removing and installing Page 20
-40
- Electrically check fuel pump Page 20
-
31

- Check the residual pressure14 -
Fuel strainer
Connected to fuel supply unitCan not be individually replaced
- Clean if dirty
15 -
Surge housing lower section Mounted in fuel tankCan not be removedDisconnecting: press unlatching buttons on
connector piece
Pa
ge 25 of 49 Fuel su
pp
ly system, servicin
g (vehicles with front wheel drive and 1.8 ltr. turbo or 2.8 ltr. en
gine
)
11/19/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.GE04.20.2

20-34


If specified value obtained but no running noise audible from pump
WARNING!
Fuel system is under pressure! Before opening, place clean cloths
around the connections to be opened. Carefully loosen the
connections to relieve pressure. - Switch Fluke 83 multimeter to 20 Volt range and connect to terminal 1
(green/yellow) and 4 (brown) of harness connector using jumper wires
from VW 1594 Adaptor kit.
- Press remote control switch continuously while reading Voltage.
Specified value: approx. Battery Voltage.
- Remove cover flange as follows:

- Mark supply line -2- and return line -3- and remove from cover flange.
Pa
ge 30 of 49 Fuel su
pp
ly system, servicin
g (vehicles with front wheel drive and 1.8 ltr. turbo or 2.8 ltr. en
gine
)
11/19/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.GE04.20.2

20-38

Vehicles with 1.8 ltr. turbo engine

WARNING!

Fuel system is under pressure! Before
opening, place clean cloths around the
connections to be opened. Carefully loosen
the connections to relieve pressure.

Vehicles with 2.8 ltr. engine
WARNING!
Fuel system is under pressure! Before opening, place clean cloths
around the connections to be opened. Carefully loosen the
connections to relieve pressure. - Disconnect fuel return hose from connection on fuel distributor line.
- Connect auxiliary hose -arrow- to distributor line and hold in measuring
container.

- Disconnect fuel return hose from hose connection on fuel distributor
line.
- Connect auxiliary hose -arrow- to distributor line and hold in measuring
container.
Pa
ge 34 of 49 Fuel su
pp
ly system, servicin
g (vehicles with front wheel drive and 1.8 ltr. turbo or 2.8 ltr. en
gine
)
11/19/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.GE04.20.2

20-41

- Open fuel-filler cap briefly and close again.

- If necessary, drain fuel tank using fuel cart
Page 20
-18
.

Note:

The fuel tank must not be filled more than
1/3
maximum.

- Remove connector flange cover under luggage
compartment trim.

WARNING!

Fuel system is under pressure! Before
opening, place clean cloths around the
connections to be opened. Carefully loosen
the connections to relieve pressure.

- Mark return line -2- and supply line -3- and pull off of cover flange.
- Unlatch and disconnect 4-pin harness connector -1-.
Pa
ge 37 of 49 Fuel su
pp
ly system, servicin
g (vehicles with front wheel drive and 1.8 ltr. turbo or 2.8 ltr. en
gine
)
11/19/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.GE04.20.2