AUDI A4 1998 B5 / 1.G AFC Engine Multiport Fuel Injection System Servising Workshop Manual

24-7


Multiport Fuel Injection (MFI)
system, servicing CAUTION!
Fire hazard! Do not smoke, work near heaters or
open flame, or have anything in the area that
could ignite fuel.
Safety measures page 24
-13

Rules of cleanliness page 24-15

Notes:
Before starting any repair work on the fuel
injection system, check Diagnostic Trouble
Code (DTC) memory and carry out component
functional checks using the output Diagnostic
Test Mode (DTM).
Always replace seals.
Check DTC memory (scan tool function 02)
page 01
-13
.
Output Diagnostic Test Mode (scan tool function
03) page 01
-145
.
Pa
ge 1 of 13 Multi
port Fuel In
jection
(MFI
) system, servicin
g
11/22/2002 htt
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play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU01.24.2

24-8


1 -
Fuel return line
25 Nm (18 ft lb)
2 -
10 Nm (7 ft lb)
3 -
Safety clip for pressure regulator
4 -
O-ring Always replace
5 -
Pressure regulator Check system and holding pressure
page 24
-20

6 -
Fuel rail
7 -
Fuel supply line
25 Nm (18 ft lb)
8 -
Fuel injector safety clips
9 -
O-ring Always replace
10 -
Fuel injectors Checking page 24
-29
11 -
O-ring
Always replace
12 -
Intake manifold
Pa
ge 2 of 13 Multi
port Fuel In
jection
(MFI
) system, servicin
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11/22/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU01.24.2

24-9


CAUTION!
Fire hazard! Do not smoke, work near heaters or
open flame, or have anything in the area that
could ignite fuel.
Safety measures page 24
-13

Rules of cleanliness page 24-15

Notes:
Before starting any repair work on the fuel
injection system, check Diagnostic Trouble
Code (DTC) memory and carry out component
functional checks using the output Diagnostic
Test Mode (DTM).
Always replace seals.
Check DTC memory (scan tool function 02)
page 01
-13
.
Output Diagnostic Test Mode (scan tool function
03) page 01
-145
.
Pa
ge 3 of 13 Multi
port Fuel In
jection
(MFI
) system, servicin
g
11/22/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU01.24.2

24-10


1 -
Intake manifold, upper
2 -
10 Nm (7 ft lb)
3 -
20 Nm (15 ft lb)
4 -
Seal
Always replace
5 -
Idle Air Control (IAC) valve -N71- Checking page 24
-37
6 -
10 Nm (7 ft lb)
7 -
6 Nm (53 in. lb)
8 -
Flange
9 -
Intake manifold, lower
10 -
Seal
Always replace
11 -
10 Nm (7 ft lb)
12 -
Vacuum hose For intake manifold change-over valve
13 -
20 Nm (15 ft lb)
14 -
Throttle body
Pa
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port Fuel In
jection
(MFI
) system, servicin
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11/22/2002 htt
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play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU01.24.2

24-11


15 -
Seal
Always replace
16 -
20 Nm (15 ft lb)
17 -
EGR valve
18 -
EGR temperature sensor -G98- On intake manifold lower section beneath
throttle body
19 -
10 Nm (7 ft lb)
20 -
Seal Always replace
21 -
10 Nm (7 ft lb)
Pa
ge 5 of 13 Multi
port Fuel In
jection
(MFI
) system, servicin
g
11/22/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU01.24.2

24-12
Multiport fuel injection system, technical data

Engine code
AFC
Idle speed

Not adjustable, maintained by idle speed
control 650 - 750 RPM
RPM upper limit
Actuated by switching off fuel injectors 6200 RPM
CO content in front of Three Way Catalytic
Converter (TWC)
Not adjustable, controlled by ECM 0.2 - 1.2 Vol. %
Fuel pressure
At idle, with vacuum hose: Connected Approx. 3.2 - 3.8 bar
(46 - 55 psi)
Disconnected Approx. 3.8 - 4.2 bar
(55 - 61 psi)
Residual pressure
After 10 minutes with: Cold engine 2.2 bar (32 psi)
Warm engine 3.0 bar (44 psi)
Fuel injectors: Spray pattern: Approx. the same for all fuel
Pa
ge 6 of 13 Multi
port Fuel In
jection
(MFI
) system, servicin
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yp
e=re
pair&id=AUDI.B5.FU01.24.2

injectors
Fuel injection quantity using output Diagnostic
Test Mode (DTM) 85 - 110 ml (2.9 - 3.7 oz.)
Single fuel injector resistance:
Bosch: 15 - 17
Siemens: 13.5 - 15.5
Pa
ge 7 of 13 Multi
port Fuel In
jection
(MFI
) system, servicin
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11/22/2002 htt
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yp
e=re
pair&id=AUDI.B5.FU01.24.2

24-13

Safety measures


WARNING!

Be alert when working on or near the engine.
High ignition secondary voltage can cause
serious personal injury and damage vehicle
components.

DO NOT touch or disconnect ignition system
wires when the engine is running or being
cranked at starting RPM.
DO NOT operate the starter if the fuel
injectors have been removed.

Be sure the ignition is switched OFF, when:
Disconnecting ignition wires
Disconnecting fuel injection system wiring
Connecting or disconnecting test equipment
leads
Disconnecting the battery
Washing the engine or engine
compartment.
Pa
ge 8 of 13 Multi
port Fuel In
jection
(MFI
) system, servicin
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11/22/2002 htt
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e=re
pair&id=AUDI.B5.FU01.24.2

BEFORE cranking the engine at starting RPM
(such as for compression testing) disable the
ignition and fuel injection systems:

Disconnect the ignition coil power output
stage.
Disconnect harness connectors from all fuel
injectors.
After the work is completed, erase
Diagnostic Trouble Code (DTC) memory.
Pa
ge 9 of 13 Multi
port Fuel In
jection
(MFI
) system, servicin
g
11/22/2002 htt
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yp
e=re
pair&id=AUDI.B5.FU01.24.2

24-14

CAUTION!

BEFORE disconnecting the battery:

Stop the engine.
Be sure the ignition is switched OFF (also
applies when connecting the battery). Failure
to do so may damage the Engine Control
Module (ECM).
Be sure of the proper radio code (for vehicles
equipped with coded anti-theft radio).

Be sure the battery negative (-) cable is
disconnected, when:
Working on the electrical system
Resistance (spot) welding or electric arc
welding anywhere on the vehicle.

When connecting and disconnecting
electrical test equipment (LED voltage tester,
multimeter, etc.):
Be sure the ignition is switched OFF.
Use correct adapters from the VW 1594
Pa
ge 10 of 13 Multi
port Fuel In
jection
(MFI
) system, servicin
g
11/22/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU01.24.2