fuel AUDI A4 1998 B5 / 1.G AWM Engine Motronic Injection System Servicing Workshop Manual

24-1


Motronic injection system,
servicing

Safety precautions

If special testing equipment is required during
road test, note the following:

WARNING!

Test equipment must always be secured to
the rear seat and operated from there by a
second person.
If test and measuring equipment is operated
from the passenger seat, the person seated
there could be injured in the event of an
accident involving deployment of the
passenger-side airbag.
To reduce the risk of personal injury and/or
damage to the fuel injection and ignition system,
always observe the following:
Only disconnect and reconnect wires for
injection and ignition system, including test
leads, when ignition is turned off.
If engine is to be cranked at starting RPM
without starting (e.g. for compression testing),
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disconnect connector from ignition coils and
from fuel injectors.
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24-2

It is possible that the control module will
recognize a malfunction and store a DTC during
some tests. After completing all tests and
repairs, DTC memory should therefore be
checked and erased if necessary. Readiness
code must be generated after DTC memory is
erased Page 01
-84
.

Always switch ignition off before cleaning
engine.
The battery should only be disconnected and
reconnected when the ignition is turned off,
since otherwise the Engine Control Module
(ECM) can be damaged.

WARNING!

Fuel system is under pressure! Before
opening system, place rags around the
connection point. Then release pressure by
carefully loosening connection.
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24-3

Rules of cleanliness

When working on the fuel supply or fuel injection
systems, the following "6 rules of cleanliness"
should be carefully observed:

Thoroughly clean all connections and the
surrounding area before disconnecting.
Place parts that have been removed on a clean
surface and cover. Use lint-free cloths only!
Carefully cover over opened components or
seal, if repairs are not carried out immediately.
Only install clean components: Only unpack
replacement parts immediately prior to
installation. Do not use parts that have been
stored loose (in tool boxes etc.)
When the system is open: Do not work with
compressed air if it can be avoided. Do not
move vehicle unless absolutely necessary.
Disconnected electrical harness connectors:
Protect from dirt and moisture. Be sure harness
connector is dry before connecting.
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24-4
Technical data

Engine identification

AWM (1.8 L / 5V/ 125 kW-engine)
Idle speed
Engine speed cannot be adjusted, it is regulated by idle
stabilization
Front Wheel Drive
(FWD)
All Wheel Drive (AWD)
740 to 860 RPM
760 to 880 RPM
Engine speed (RPM) limitation
via fuel injector shut-off
about 6800 RPM
Fuel pressure at idle speed Vacuum hose
connected
about 3.5 bar positive pressure

Vacuum hose
disconnected
about 4.0 bar positive pressure
Residual pressure after 10 min. at least 2.5 bar positive pressure
Fuel injectors Injection stream Dual-hole nozzle / same for all
injectors

Injection quantity (30 s)
135 10 ml

Resistance
(room temperature)
12 to 13
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24-7


Repair Manual, 1.8 Liter 4
-Cyl. 5V Turbo Engine
Mechanical, Engine Code(s): AWM, Repair Group 26; Secondary Air Injection (AIR) system, checking

6 -
Fuel pressure regulator
Checking Page 24
-32
7 -
Engine Speed (RPM) sensor -G28-
Checking Page 28
-27
8 -
Secondary Air Injection (AIR) solenoid
valve-N112-
Installation location Fig. 4
, Page
24
-14

Checking:Green harness connector
9 -
Bracket for harness connectors Component location Fig. 1
, Page
24
-13

Accessible with coolant expansion tank
unbolted and swung to the side.
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24-11


17 -
Intake Air Temperature (IAT) sensor -G42-
Checking Page 28
-21
18 -
Recirculating valve for turbocharger-
N249-
Installation location Fig. 4
, Page
24
-14

Blue harness connector
19 -
Knock Sensor (KS) 1 -G61-
20 -
Knock Sensor (KS) 2 -G66-
21 -
Camshaft Position (CMP) sensor 2 -G40- Checking Page 28
-49
22 -
Fuel injector
Cylinder 1 Fuel Injector -N30-Cylinder 2 fuel injector -N31-Cylinder 3 fuel injector -N32-Cylinder 4 fuel injector -N33-Checking Page 24
-37
Removing and installing Page 24
-45
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24-13


The following harness connectors are located below the coolant
expansion tank: Fig. 1 Installation location, harness connectors
1 - 4-pin harness connector, brown
for Oxygen Sensor (O2S) behind Three Way Catalytic Converter
(TWC) -G130- and Oxygen Sensor (O2S) Heater 1 -Z29- (bank 1
sensor 2)
2 - 6-pin harness connector, black
for Heated Oxygen Sensor (HO2S) -G39- beforecatalytic converter
and Oxygen Sensor (O2S) Heater -Z19- (bank 1 sensor 1)
3 - 3-pin harness connector, gray
for Engine Speed (RPM) sensor -G28-
4 - 3-pin harness connector, blue
for Knock Sensor (KS) 2 -G66-
5 - 3-pin harness connector, green
for Knock Sensor (KS) 1 -G61-

Fuel Pump (FP) Relay -J17- is located at position 4 of central electronics
in driver's footwell, left. Fig. 2 Component locations Fuel Pump (FP) Relay -J17-
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24-32

System pressure, fuel pressure
regulator and residual pressure,
checking


Note:
Fuel pressure regulator regulates fuel pressure
according to intake manifold pressure. This
ensures that the pressure drop at the fuel
injectors remains the same for each speed and
load range of the engine.

Special Tools and Equipment

Test requirements:
Repair Manual, Fuel Supply System, Repair Group 20

VAG1318V.A.G 1318 with V.A.G 1318/11 adapter, V.A.G 1318/12 pressure
hose with connectors and V.A.G 1318/13 adapter Fuel Pump (FP) relay OK; checking Page 24
-52
.
Fuel Pump (FP) OK, checking: Fuel filter OK Battery voltage at least 12.7 V Vehicles with automatic transmission Selector lever in P or N.
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24-33

Checking system pressure

- Open fuel filler flap briefly (pressure release).

WARNING!
Fuel system is under pressure! Before opening system, place rags
around the connection point. Then release pressure by carefully
loosening connection. - Remove engine cover (arrows).

- Open threaded connection (arrow) and catch exiting fuel using a rag.
- Connect VAG1318 pressure gauge in supply line using adapters
1318/11, 1318/12 and 1318/13.
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