DIRECT PETROL INJECTION SYSTEM

Description 1056F

2.0 JTS

CONSTRUCTION FEATURES

General view

1 - Electric fuel pump

2 - Relays

3 - Lambda sensors upstream of catalytic preconverters

4 - Lambda sensors downstream of catalytic preconverters

5 - Speedometer

6 - Rev counter

7 - Engine Check warning light

8 - Timing sensor

9 - Climate control connector

10 - Diagnostic connector

11 - Alfa Romeo CODE connector

12 - Injection/ignition control unit

13 - Injectors

14 - Coolant temperature sensor

15 - Rpm sensor

16 - Air flow meter with air temperature sensor

17 - Ignition coils

18 - Knock sensor

19 - Fuel vapour recirculation solenoid valve

20 - Accelerator pedal with built-in potentiometer.

21 - Clutch pedal switch

22 - Brake pedal switch

23 - Throttle body integral with D.V.L.

24 - CAN line

25 - Modular intake manifold solenoid valve

26 - Variable valve timing

Injection-ignition control unit MED7.1.1

The control unit is fitted in the engine compartment, on the intake chamber.

The control unit memory is the 'flash EPROM type, i.e. reprogrammable from the outside without intervening on the hardware.

The adoption of the Alfa Romeo CODE does not allow control units to be exchanged between vehicles.

Replacement of the injection control unit, air capacity case or the throttle body integral with the D.V.E. means that the self-learning procedure has to be carried out.

PIN-OUT

K1 - Electronic earth

K2 - Electronic earth

K3 - Ignition-operated power supply, via main relay

K4 - Electronic earth

K5 - Ignition-operated power supply, via main relay

K6 - Ignition-operated power supply, via main relay

K7 - Compressor relay control

K8 - Fuel level signal

K9 - Not connected

K10 - Air temperature sensor signal

K11 - Not connected

K12 - Not connected

K13 - Not connected

K14 - Not connected

K15 - Air flow meter

K16 - Air flow meter reference earth

K17 - 5 Volt output

K18 - Vehicle speed signal

K19 - Not connected

K20 - Brake light switch

K21 - Cruise Control Resume

K22 - Not connected

K23 - Clutch pedal switch

K24 - Quadrinary - fan 2nd speed request

K25 - Main relay activation

K26 - Engine temperature for climate control system

K27 - Not connected

K28 - Fuel pump relay

K29 - Lambda sensor heating (front cat. 2)

K30 - Not connected

K31 - Not connected

K32 - Not connected

K33 - Not connected

K34 - Not connected

K35 - Not connected

K36 - Not connected

K37 - Not connected

K38 - Not connected

K39 - Not connected

K40 - Compressor activation request

K41 - Cruise Control ON/OFF

K42 - Not connected

K43 - Cruise Control SET -

K44, Cruise Control SET +

K45 - Quadrinary - Fan 1st speed request

K46 - Not connected

K47 - Not connected

K48 - Not connected

K49 - Lambda sensor heater (rear cat. 1)

K50 - Not connected

K51 - Not connected

K52 - LA1 lambda sensor (front cat. 1)

K53 - Lambda sensor signal (front cat. 1)

K54 - Not connected

K55 - Lambda sensor (rear cat. 2)

K56 - Lambda sensor reference earth (rear cat. 2)

K57 - Lambda sensor earth (front cat. 2)

K58 - Lambda sensor (front cat. 2)

K59 - Earth for potentiometer - 1 accelerator pedal

K60 - Signal for potentiometer - 1 accelerator pedal

K61 - 5 Volt output for accelerator pedal

K62 - Not connected

K63 - CAN 2 - H line

K64 - CAN 1 - H line

K65 - Brake lights

K66 - Rev counter signal

K67 - Ignition-operated signal to control unit (pin 15)

K68 - Fuel consumption signal

K69 - 2nd speed fan control

K70 - Direct power supply

K71 - Output for engine coolant temperature warning light

K72 - Alfa Romeo CODE connection

K73 - Lambda sensor heater (front cat. 1)

K74 - Lambda sensor (ant. cat. 1)

K75 - Lambda sensor earth (front cat. 1)

K76 - Lambda sensor reference earth (front cat. 1)

K77 - Lambda sensors (front cat. 1)

K78 - Not connected

K79 - Lambda sensor signal (front cat. 2)

K80 - LA1 lambda sensor (front cat. 2)

K81 - Earth for potentiometer - 2 accelerator pedal

K82 - Signal for potentiometer - 2 accelerator pedal

K83 - 5Volt output for accelerator pedal module

K84 - Not connected

K85 - CAN 2 - L line

K86 - CAN 1 - L line

K87 - Diagnostic connection (K line)

K88 - Not connected

K89 - Injection warning light

K90 - Not connected

K91 - Cruise Control warning light

K92 - Not connected

K93 - Fan 1st speed control

K94 - Lambda sensor heater (front cat. 2)

A1 - Injector 1

A2 - Injector 3

A3 - Not connected

A4 - Not connected

A5 - Fuel pressure regulator

A6 - Variable geometry activation

A7 - Not connected

A8 - Not connected

A9 - Engine coolant temperature

A10 - Not connected

A11 - Not connected

A12 - Not connected

A13 - Potentiometer - 1 throttle body

A14 - 5 volt output for throttle body

A15 - Throttle opening motor

A16 - Injector 4

A17 - Not connected

A18 - Injector 2

A19 - Not connected

A20 - Not connected

A21 - Reference earth (cam angle sensor, fuel pressure sensor, brake servo sensor)

A22 - Not connected

A23 - Not connected

A24 - Fuel pressure sensor

A25 - Not connected

A26 - 5 Volt output for fuel pressure sensor, cam angle sensor and brake servo sensor

A27 - Not connected

A28 - Throttle body potentiometer 2

A29 - Throttle body reference earth

A30 - Throttle opening motor

A31 - Injector 3

A32 - Not connected

A33 - Injector 1

A34 - Not connected

A35 - Not connected

A36 - Variable valve timing control

A37 - Cylinder 2 coil control

A38 - Cylinder 4 coil control

A39 - Cylinder 3 coil control

A40 - RPM sensor, connector A

A41 - Timing sensor

A42 - Brake servo sensor pressure signal

A43 - Not connected

A44 - Knock sensor

A45 - Not connected

A46 - Injector 2

A47 - Not connected

A48 - Injector 4

A49 - Not connected

A50 - Not connected

A51 - Oil pressure switch

A52 - Not connected

A53 - Not connected

A54 - Cylinder 1 coil control

A55 - Engine rpm sensor, connector B

A56 - Not connected

A57 - Sensor reference earth

A58 - Not connected

A59 - Knock sensor

A60 - Fuel vapour solenoid control

INJECTORS

These are fitted on the cylinder head and operated by the injection control unit.

They are fastened by means of a fork secured to the head with a nut.

The injector has a single opening with the fuel sprayed at an angle of 60°.

1 - Fuel intake

2 - O-ring

3 - Electrical connection

4 - Teflon ring

5 - Armature

6 - Coil

PRESSURE PUMP

This is radial jet type with three radial pistons and is driven by the exhaust camshaft via a spacer.

With the engine started, the fuel pressure in the rail is around 50 bar during idling.

During operation, the pressure in the rail can reach a maximum of 100 bar depending on the engine load conditions.

The maximum pressure produced by the pressure pump is around 120 bar (if the pressure regulator is stuck).

The pressure pump must be supplied with a pressure of at least 4.5 bar; so the fuel system has an auxiliary pump immersed in the fuel tank.

The pressure pump is lubricated and cooled by the same fuel by means of suitable ducts.

1 - Cylinder

2 - Cam

3 - Piston

4 - Pump shaft

5 - Dynamic seal

6 - Check valve

ENIGINE COOLANT TEMPERATURE SENSOR

This is fitted on the thermostat cup. The sensitive elements (2 NTC type), contained in a single body, translate temperature changes into resistance changes to measure coolant temperature.

The sensor is produced using semiconductor technology, so if the temperature of the sensor increases as the temperature of the coolant increases, the resistance decreases.

As the variation in resistance is not linear, for the same temperature increment, it is higher for low temperatures than for high temperatures.

The following functions are affected by the sensor:

• coolant temperature information to the engine control unit
• information for the instrument panel required for readings displayed to the driver.

The NTC earth connection is insulated from the sensor case; the sensor therefore comes with a four-way electrical connection.

The engine coolant temperature sensor also informs the climate control unit.

DETONATION SENSOR

The piezoelectric knock sensor is fitted on the cylinder block/crankcase and detects the intensity of the vibrations caused by the detonation in the combustion chambers.

The piezoelectric crystal forming the sensor detects the vibrations generated at a frequency of between 12 and 16 kHz, and transforms them into electrical signals sent to the fuel injection control unit.

RPM SENSOR

It is fitted on the engine block, where it faces the phonic wheel located on the crankshaft.

The electrical connector of this sensor is built into the sensor case.

Operation

The sensor consists of a tubular casing (1) which contains a permanent magnet (3) and an electrical winding (2).

As the flywheel teeth go past, the magnetic flow produced by the magnet (3) undergoes fluctuations due to the change in the gap.

These fluctuations induce an electromotive force in the winding (2), at the ends of which there is a voltage which alternates between positive (tooth opposite sensor) and negative (gap opposite sensor).

The peak value of the output voltage from the sensor, provided other factors remain the same, depends on the distance between the sensor and tooth (gap).

TIMING SENSOR

Hall effect; it is mounted on the cylinder head and 'facing' the exhaust camshaft pulley.

The engine control unit uses the timing sensor signal for recognizing T.D.C. at the end of compression for a quick start.

ACCELERATOR PEDAL WITH BUILT-IN POTENTIOMETER

The sensor consists of a casing, secured to the accelerator pedal mount, which contains a shaft, in an axial position, connected to two potentiometers: one main one and one safety one.

The engine control unit implements the following recovery strategies:

• if there is a fault with one of the two potentiometers, a throttle opening of up to 25% is allowed for a long period
• if both of the potentiometers fail completely, or one potentiometer and the brake pedal switch fail, the throttle opening is excluded.

There is a coil spring on the shaft which guarantees the correct resistance to the pressure whilst a second spring ensures the return on release.

Operation

The position of the accelerator pedal is transformed into an electrical voltage signal and is sent to the fuel injection control unit by the potentiometer connected to the accelerator pedal.

The accelerator pedal position signal is processed together with the information relating to the rpm, to obtain the fuel injection times and relevant pressure.

THROTTLE BODY WITH DVL

It is fitted on the inlet chamber and regulates the quantity of air drawn in by the engine.

According to the signal coming from the accelerator pedal potentiometer, the injection control unit controls the opening of the throttle by means of a direct current motor integrated in the throttle body integrated with D.V.L.

The throttle opening takes place between 0° and 80° therefore including the idle adjustment.

The throttle body integral with D.V.L. is equipped with two potentiometers integrated so that one controls the other and viceversa.

If both the potentiometers fail or there is no supply, depending on the position of the accelerator pedal, the control unit reduces the drive torque:

• fully depressed, it cuts off the supply to one or more pistons, until a maximum speed of 2500 rpm is reached.
• in intermediate positions, it cuts off the supply to one or more pistons, until a speed below 2500 rpm is reached.

If the throttle body integrated with D.V.L. or the injection control unit or the air chamber is replaced then the self-learning procedure must be carried out.

Air flow meter

The flow meter is built into the air filter case and is hot film type.

The intake air temperature sensor is built into the flow meter.

1 - Covers

2 - Electronic card

3 - Sensor

4 - Support plate

5 - Support

6 - O-ring

7 - Temperature sensor

The air flow meter cannot be dismantled.

Operation

The operating principle is based on a heated diaphragm located in a measuring duct through which the intake air entering the engine flows.

The hot film diaphragm is kept at a constant temperature (about 120°C above the incoming air temperature) by the heating resistor.

The air mass passing through the measuring duct tends to draw heat from the diaphragm, so to keep the latter at a constant temperature, some current must flow through the resistor.

This current is measured by a suitable Wheatstone bridge.

The current is therefore proportional to the mass of flowing air.

The flow meter directly measures the air mass (not volume), thus eliminating problems of temperature, altitude, pressure, etc.