AUDI TT 1998 8N / 1.G ATW Engine Motronic Fuel Injection Syst

24-1


Motronic fuel 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
-73
.

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

ATW (1.8 L / 5V/ 110 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
800 to 920 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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24-5


Component locations, overview

Note:
Component location without illustration:
----
- Leak Detection Pump (LDP) -V144-
Behind rear left wheelhousing liner
1 -
Evaporative Emission (EVAP) canister
purge regulator valve -N80- Checking Page 24
-107
2 -
Heated Oxygen Sensor (HO2S) -G39-
before catalytic converter, 55 Nm
Continuous oxygen sensorCheck Oxygen Sensor (O2S) and oxygen
sensor control before Three Way Catalytic
Converter (TWC) Page 24
-71

Check aging of oxygen sensor before
catalytic converter Page 24
-83

Check oxygen sensor heater for Oxygen
Sensor (O2S) before Three Way Catalytic
Converter (TWC) Page 24
-99

Removing and installing Page 24
-105
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24-6


Repair Manual, 1.8 Liter 4
-Cyl. 5V Turbo Engine
Mechanical, Engine Code(s): AEB, ATW, Repair Group 26; Secondary Air Injection (AIR) system, checking
3 -
Oxygen Sensor (O2S) behind Three Way
Catalytic Converter (TWC) -G130-, 55 Nm Check Oxygen Sensor (O2S) and oxygen
sensor control behind Three Way Catalytic
Converter (TWC) Page 24
-87

Check oxygen sensor heater for Oxygen
Sensor (O2S) behind Three Way Catalytic
Converter (TWC) Page 24
-99

Removing and installing Page 24
-105
4 -
Combination valve for secondary air
injection (AIR)
Checking, removing and installing:
5 -
Engine Coolant Temperature (ECT) sensor
-G62-
Checking Page 28
-30
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24-7


Repair Manual, 1.8 Liter 4
-Cyl. 5V Turbo Engine
Mechanical, Engine Code(s): AEB, ATW, Repair Group 26; Secondary Air Injection (AIR) system, checking
6 -
Fuel pressure regulator Checking Page 24
-33
7 -
Engine Speed (RPM) sensor -G28-
Checking Page 28
-26
8 -
Secondary Air Injection (AIR) solenoid
valve-N112-
Installation position Page 24
-14
, Fig.
4
Checking:Green harness connector
9 -
Bracket for harness connectors Component location Page 24
-13
, Fig.
1

Accessible with coolant expansion tank
unbolted and swung to the side.
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24-8


10 -
Instrument cluster
With exhaust Malfunction Indicator Lamp
(MIL). Notes for Malfunction Indicator Lamp
(MIL) Page 01
-3
with fault light for power accelerator
activation -K132- (EPC warning lamp).
Significance of EPC warning lamp Page 24
-115

11 -
Throttle Position (TP) sensor -G79- and
sender 2 for accelerator pedal position -
G185-
Component location Page 24
-15
, Fig.
5

Checking Page 24
-133
Adapt kick down function Page 24
-139
12 -
Brake light switch -F- and brake pedal
switch -F47-
Component location Page 24
-14
, Fig.
3

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24-9


Repair Manual, 1.8 Liter 4
-Cyl. 5V Turbo Engine
Mechanical, Engine Code(s): AEB, ATW, Repair Group 26; Secondary Air Injection (AIR) system, checking
13 -
E-box, plenum chamber Installation locations Page 24
-15
, Fig.
6

Installation location for motronic Engine
Control Module (ECM) -J220- with
integrated Barometric pressure (BARO)
sensor -F96- Check voltage supply of Engine Control
Module (ECM) Page 28
-36

Procedure to follow after open circuit in
voltage supply Page 24
-22

Replacing Engine Control Module (ECM)
Page 24
-23

Installation location of Secondary Air
Injection (AIR) pump relay -J299- Check Secondary Air Injection (AIR) pump
relay -J299-:
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