fuel AUDI A3 1999 8L / 1.G ATW Engine Ignition System Workshop Manual

28-2

Safety precautions

To reduce the risk of personal injury and/or
damage to the fuel injection and ignition system,
always observe the following:

Do not touch or disconnect ignition wires when
engine is running or turning at starting RPM.
Always switch ignition off before disconnecting
or reconnecting wires for the injection and
ignition system, including high voltage wiring
and test leads.
If engine is to be cranked at starting RPM
without starting (e.g. for compression testing),
disconnect connector from ignition coils and
from fuel injectors.
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.
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28-3
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): 740 to 860 RPM
All-Wheel Drive Vehicles: 800 to 920 RPM
Engine speed (RPM) limitation
Via fuel injector shut-off
about 6800 RPM
Ignition timing is determined in the control
module
It is not possible to adjust the ignition
timing
Ignition system Single coil ignition system with 4 ignition coils (power output stages integrated)
that are connected directly to spark plugs via the ignition cables.
Spark plugs Tightening torque 30 Nm.
Firing sequence 1-3-4-2
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28-5

Test sequence

Note:
The ignition coil and power output stage are
combined in one complete component.

Recognize a non-functional or misfiring cylinder as follows:
If misfires were recognized:
If no misfires were recognized:
or
If faulty cylinder is recognized: - Remove engine cover (arrows).
- Check misfire recognition Page 28
-51
.
- Continue with test at indicated cylinder "If faulty cylinder is
recognized". - Disconnect connectors from fuel injectors in sequence with engine
running and observe engine operation.
- Compare spark plugs from all cylinders to each other. Check
electrodes for carbon fouling..
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28-10

- Perform following tests marked with dots:

Checking activation of power output stages
Note:
Fuel must not be injected during the test to avoid damaging catalytic
converter. Connectors must therefore be disconnected from fuel injectors.
Check wire connection from 3-socket relay carrier, position 2, terminal
6 to harness connector at ignition coil terminal 1. Check motronic Engine Control Module (ECM) power supply relay -
J271- Page 28
-13
.
- Remove all harness connectors to injectors.
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28-40

Knock recognition control stop,
checking

If a DTC is stored regarding "Knock control
regulation limit reached":

- Perform following tests:

Possible cause
Corrective action
DTC for all cylinders

Poor fuel quality
Operating instructions - Change fuel quality
or
Cylinder 1/2 or 3/4
Knock sensor tightened to incorrect torque- Loosen knock sensors and tighten to 20 Nm

Knock sensor faulty- Check knock sensor Page 28
-41


Corrosion at harness connector- Check harness connector

Engine accessories loose- Secure engine accessories
DTC for one Cylinder
Engine damage- Check compression pressure

Engine accessories loose- Secure engine accessories
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28-55
Evaluation display group 014, display field 3 and display group 015 and 016, display fields 1, 2 and 3. Display field:
3
Possible cause
Corrective action
Larger than 0

spark plug faulty
spark plug connector faulty
Ignition coil or power output stage
faulty - Check spark plugs and ignition wires with connector
- Ignition coils with power output stages. Checking Page
28
-4


Fuel injector faulty- Check fuel injectors Page 24
-38
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