2003 AUDI A8 fuel

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Attention
NoteNew
Contents
Page
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Body . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Passenger Protection
System layout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Block diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Safety systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Engine, Mechanics
Technical data of V8 4.2 l 5V engine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
Technical data of V8 3.7 l 5V engine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
System layout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
Electrohydraulic torque reaction support . . . . . . . . . . . . . . . . . . . . . . . . . 32
Exhaust system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
Fuel tank . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
Automatically controlled starting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
Gearbox . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
Running Gear
Front axle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
Rear axle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50
4-level air suspension . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
System layout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52
Electric parking brake . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53
Adaptive cruise control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54
Electrical System
Bus topology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58
Convenience and security electronics . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64
Lighting system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68
Heating/Air Conditioner
Design and operation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72
Operating principle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74
Blower unit/air routing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76
System layout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80
Block diagram for front air conditioner . . . . . . . . . . . . . . . . . . . . . . . . . . . 86
Block diagram for rear air conditioner . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88
The Self Study Programme contains information on design
features and functions.
The Self Study Programme is not intended as a Workshop
Manual. Values given are only intended to help explain the
subject matter and relate to the software version applicable at
the time of SSP compilation.
Use should always be made of the latest technical publications
when performing maintenance and repair work.

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Engine, Mechanics
200040006000
40
60
80
100
120
140
160
180
200
220
240
260
280 300
320
340 360380 400
420 440
460
Technical data
V8 4.2 l 5V engine
Engine code
letters: BFM
Capacity:
3
Bore: 84.5 mm
Stroke: 93.0 mm
Compression
ratio: 11 : 1
Power: 246 kW (335 hp)
at 6,500 rpm
Torque: 430 Nm at 3,500 rpm
Camshaft
adjustment
range: 22° CS advance
Valves: 5 per cylinder
Engine
management: ME7.1.1
Emission
standard: EU 4
Firing
order: 1 - 5 - 4 - 8 - 6 - 3 - 7 - 2
Capacities: 7.5 l engine oil (incl. filter)
Consumption: Urban: 17.5 - 17.6 l/100 km Non-urban: 8.7 - 8.8 l/100 km
Average: 11.9 - 12.0 l/100 km
Acceleration
0 - 100 km/h: 0 - 80 km/h – 4.8 s 0 - 100 km/h – 6.3 s
Fuel: Premium Plus Unleaded 98/95 RON
CS = Crankshaft
SSP282_002
SSP282_012
Engine speed [rpm]
P
ower [kW]
T
orq ue [Nm]
4,172 cm

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200040006000
260
280 300
320
340 360380 400
420 440
46040
60
80
100
120
140
160
180
200
220
240
V8 3.7 l 5V engine
Engine code
letters: BFL
Capacity:
3
Bore: 84.5 mm
Stroke: 82.4 mm
Compression
ratio: 11 : 1
Power: 206 kW (280 hp)
at 6,000 rpm
Torque: 360 Nm at 3,750 rpm
Camshaft
adjustment
range: 13° CS advance
Valves: 5 per cylinder
Engine
management: ME7.1.1
Emission
standard: EU 4
Firing
order: 1 - 5 - 4 - 8 - 6 - 3 - 7 - 2
Capacities: 7.5 l engine oil (incl. filter)
Consumption: Urban: 17.1 - 17.3 l/100 km Non-urban: 8.6 - 8.8 l/100 km
Average: 11.7 - 11.9 l/100 km
Acceleration
0 - 100 km/h: 0 - 80 km/h – 5.6 s 0 - 100 km/h – 7.3 s
Fuel: Premium Plus Unleaded 98/95 RON
SSP282_001
SSP282_011
Engine speed [rpm]
P
ower [kW]
T
orq ue [Nm]
3,697 cm

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Hot-film air-mass meter G70
Engine speed sender G28
Hall sender G40 (bank 2) and
Hall sender 2 G163 (bank 1)
Lambda probe G39
(bank 1)
Lambda probe II G108
(bank 2)
Lambda probe after catalyst G130
(bank 1)
Lambda probe II after catalyst G131
(bank 2)
Throttle valve control
part J338 with
Throttle valve drive G186
(electric power control)
Throttle valve drive angle sender 1 G187
Throttle valve drive angle sender 2 G188
Coolant temperature sender G62
Knock sensor I G61 (bank 1) and
Knock sensor II G66 (bank 2)
Additional signals:
– Air conditioner requirement
– Cruise control switch
– Term. 50, stage 1
– Automatic gearbox selector lever positionEngine control unit J623
Steering
angle sender G85
ESP
control unit J104
Dash panel
insert CANAutomatic
gearbox
control unit J217
Airbag
control unit J234Intake manifold changeover valve
N156 and
Intake manifold changeover valve 2
N261
Left electrohydraulic engine mounting
solenoid valve N144 and
Right electrohydraulic engine mounting
solenoid valve N145
Torque rod valve N382
Lambda probe heater Z19
(bank 1) and
Lambda probe 2 heater Z28
(bank 2)
Lambda probe 1 heater
after catalyst Z29
Lambda probe 2 heater
after catalyst Z30
Additional signals:
– Starter relay term. 50, stage 2
– Tank leakage pump (USA only)
– Air conditioner compressor (out)Fuel pump relay J17
Fuel pump G6
Fuel pump II relay J49
Fuel pump G23
Injectors N30, N31, N32, N33 (bank 1)
Injectors N83, N84, N85, N86 (bank 2)
Ignition coils N (no. 1 cyl.), N128 (no. 2 cyl.),
N158 (no. 3 cyl.), N163 (no. 4 cyl.)
Ignition coils N164 (no. 5 cyl.), N189 (no. 6 cyl.),
N190 (no. 7 cyl.), N191 (no. 8 cyl.)
Activated charcoal filter system solenoid
valve 1 N80
Secondary-air pump relay J299 and
Secondary-air pump motor V101
Secondary air inlet valve N112
Throttle valve control part J338
With throttle valve drive G186
Inlet camshaft timing adjustment valve 1
N205 (bank 1)
and
N208 (bank 2) Pedal position sender/accelerator
pedal module with accelerator pedal
position sender G79 and accelerator
pedal position sender 2 G185
Brake light switch F and
Brake pedal switch F47
Clutch pedal switch F36
(manual gearbox only)
Control unit with display in dash
panel insert J285Data bus diagnostic
interface J533
Engine, Mechanics
System layout
Actuators/sensors
SSP282_091 Drive system CAN
Diagnosis CAN

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Hot-film air-mass meter G70
Engine speed sender G28
Hall sender G40 (bank 2) and
Hall sender 2 G163 (bank 1)
Lambda probe G39
(bank 1)
Lambda probe II G108
(bank 2)
Lambda probe after catalyst G130
(bank 1)
Lambda probe II after catalyst G131
(bank 2)
Throttle valve control
part J338 with
Throttle valve drive G186
(electric power control)
Throttle valve drive angle sender 1 G187
Throttle valve drive angle sender 2 G188
Coolant temperature sender G62
Knock sensor I G61 (bank 1) and
Knock sensor II G66 (bank 2)
Additional signals:
– Air conditioner requirement
– Cruise control switch
– Term. 50, stage 1
– Automatic gearbox selector lever positionEngine control unit J623
Steering
angle sender G85
ESP
control unit J104
Dash panel
insert CANAutomatic
gearbox
control unit J217
Airbag
control unit J234Intake manifold changeover valve
N156 and
Intake manifold changeover valve 2
N261
Left electrohydraulic engine mounting
solenoid valve N144 and
Right electrohydraulic engine mounting
solenoid valve N145
Torque rod valve N382
Lambda probe heater Z19
(bank 1) and
Lambda probe 2 heater Z28
(bank 2)
Lambda probe 1 heater
after catalyst Z29
Lambda probe 2 heater
after catalyst Z30
Additional signals:
– Starter relay term. 50, stage 2
– Tank leakage pump (USA only)
– Air conditioner compressor (out)Fuel pump relay J17
Fuel pump G6
Fuel pump II relay J49
Fuel pump G23
Injectors N30, N31, N32, N33 (bank 1)
Injectors N83, N84, N85, N86 (bank 2)
Ignition coils N (no. 1 cyl.), N128 (no. 2 cyl.),
N158 (no. 3 cyl.), N163 (no. 4 cyl.)
Ignition coils N164 (no. 5 cyl.), N189 (no. 6 cyl.),
N190 (no. 7 cyl.), N191 (no. 8 cyl.)
Activated charcoal filter system solenoid
valve 1 N80
Secondary-air pump relay J299 and
Secondary-air pump motor V101
Secondary air inlet valve N112
Throttle valve control part J338
With throttle valve drive G186
Inlet camshaft timing adjustment valve 1
N205 (bank 1)
and
N208 (bank 2) Pedal position sender/accelerator
pedal module with accelerator pedal
position sender G79 and accelerator
pedal position sender 2 G185
Brake light switch F and
Brake pedal switch F47
Clutch pedal switch F36
(manual gearbox only)
Control unit with display in dash
panel insert J285Data bus diagnostic
interface J533
Engine, Mechanics
System layout
Actuators/sensors
SSP282_091 Drive system CAN
Diagnosis CAN

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The tubing system for the tank breather at the
filler pipe has been considerably simplified as
compared to the predecessor model. With the
exception of diesel vehicles, the pipe
connections have been converted to quick-
release couplings.
A new feature is the use of a 2-stage delivery
pump for each tank chamber in
separate reservoirs.
The fuel level is measured by two immersion
tube senders combined with two angle
senders.
Engine, Mechanics
SSP282_007
Fuel tank
The fuel tank capacity is approximately
90 litres.
The basic unit consists of two plasma-welded
stainless steel shells. There are no differences
between petrol and diesel engine versions.
The filler neck is a single piece and welded to
the basic unit. For reasons of crash safety, the
centre section of the filler neck takes the form
of a corrugated tube.
In crash situations, this section is subject to
defined deformation to prevent cracks and
fuel spillage.
To create the best possible ergonomic
conditions for the rear passengers in
combination with maximum luggage
compartment volume, the two tank
compartments are shallower than in the
predecessor model.
The additional expansion tank has been taken
out of the filler pipe and moved to the fuel
tank.
The switch from plastic to stainless steel
was necessary for compliance with
American LEV II legislation, which
demands a further significant reduction in
permissible emission levels.
Activated charcoal filter
Fuel filler neck
Tank
compartment
breather
Diagnostic
connection

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The fuel is conveyed via the filler pipe into the
right tank chamber (as viewed in direction of
travel). The fuel passes via an additional
overflow channel at the end of the filler pipe
predominantly into the right pump reservoir.
Use of the small overflow channel ensures
that even small quantities of fuel (e.g. filling
from canister) pass directly into the pump
reservoir.
The breather function for the side
compartments is provided by two breather
pipes to the main chamber.Routing the filler pipe beneath the
longitudinal member means that the lowest
point of the pipe is not at the connection to
the fuel tank, thus producing a siphon effect.
A residual quantity of fuel remains in the filler
pipe. This necessitates a separate pipe to the
filler neck for the main chamber breather
function and for OBD II leakage diagnosis.
When the tank is full, the filler hose is closed
by a float-type shutoff valve at the end of the
filler pipe. Interior of fuel tank (filling)
SSP282_006
Baffle housing
of expansion tankReservoir
with pump unit, left Reservoir
with pump unit, rightFloat-type shutoff valve
Breather pipe
to filler pipe
Overflow channel Filler pipe

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Engine, Mechanics
Function
The main functions of the float-type rollover
valve are as follows:
– Closing-off of pipe to filler neck in the
event of rollover
– Closing in dynamic driving mode
– Closing by rising of float in valve in the
event of a brief excess of fuel in the tank
due to sloshing
Closing-off of the pipe to the activated
charcoal filter stops fuel overflowing into it. Expansion tank
The expansion tank (capacity approx. 2 litres)
consists of a plastic housing clipped to the
upper shell of the tank.
The internal expansion tank houses a float-
type rollover valve and a small suction jet
pump which constantly pumps the tank empty
whilst driving.
SSP282_009
Inlet pipe
from tank filler neck
Float-type
rollover valve
Float-type shutoff valve Breather pipe
Suction jet pump
intake connection