Audi A4, S4

since 2000 release

Repair and operation of the car

System of ignition and engine management

Main data and security measures

The system of ignition develops sparks which make firing of the soaked-up fuel-air mix. For this purpose in ignition coils voltage of 12 V will be transformed to tension of 30.000 Century.

At petrol engines with electronic ignition the control unit defines the ignition moment on the basis of the characteristic of ignition which is stored in his memory. Synchronization of work of system of ignition is carried out by signals which come to the control unit from the sensor of the Hall or the pulse sensor. Existence of anti-detonation regulation provides profitability of operation of the engine at high extent of compression and compensation of distinction of characteristics of quality of fuel. The detonation sensor on the block of cylinders registers emergence of a detonation at combustion of fuel and initiates the control unit of the engine to displace ignition in the direction "late". Thus soft functioning of the engine and lack of its damage by a detonation is ensured. Some engines have two detonation sensors on the block of cylinders.

Coil ignition/spark plug. Engine of 2.0 l of ALT

1 — the Screw 2 — Shtekernaya a level 3 — the Connecting plug 4 — the ignition Coil with an output step 5 — the Spark plug, 30nm 6 — the Connecting plug 7 — the Bolt, 10nm 8 — the Hall Sensor 9 — the Bolt, 25nm 10 — the Washer, conic 11 — the Hall sensor Cover. At installation pay attention to fixing. 12 — the Sensor of a detonation 1 13 — the Sensor of a detonation 2

14 — the Screw, 20nm. Precisely observe the tightening moment since it has impact on operation of the sensor of a detonation. 15 — the Socket three-contact green color of the sensor of a detonation 1. Fastens on a forward wall of a motive compartment in the direction of the movement, under a broad tank at the left 16 — the Socket three-contact green color of the sensor of a detonation 2. Fastens on a forward wall of a motive compartment in the direction of the movement, under a broad tank at the left

Direct ignition

Distribution of current of ignition on candles the block of electronic control operates.

Petrol engines 1.6 and 2.4 of l have 2 or 3 coils of ignition located in one case with an output step on a head of cylinders. Each coil of ignition gives tension on 2 spark plugs. Some engines have 4, 6 or 8 coils of ignition located directly on spark plugs. In this case the cable of ignition is absent.

External adjustment of the moment of ignition is not made. If the moment of ignition deviates a preset value, it is necessary to replace the damaged elements.

The system of ignition does not wear out and does not demand service. According to the schedule of maintenance it is required to replace spark plugs only.

The main data on work and sensors of control systems and injection are stated in the Section Functioning of a Control System and Injection of the Petrol Engine.

Security measures during the work with system of ignition and injection

For an exception of traumatizing people and/or damage of system of a vpryskaa of ignition it is necessary to observe the following:

• Do not concern and do not disconnect ignition wires at the working engine or at the included starter.
• Disconnect and attach pipelines of system of injection and a wire of ignition, and also electric wires of devices of measurement only at the switched-off ignition.
• Do not allow to work with electronic system of ignition to people with a warm stimulator.
• It is impossible to close the plug of 1 coils of ignition on weight.
• At an engine provorachivaniye a starter, for example, when checking pressure of a compression switch off ignition and disunite the socket of the sensor of provision of a cranked shaft.
• Do not attach a control lamp to the plug of 1 coils of ignition.