Saab 9-5

since 1997 of release

Repair and car operation

Power supply system of petrol engines

Principle of functioning of a control system of fuel injection

General information

Fuel is sucked in from a fuel tank by the electric fuel pump and moves via the fuel filter to the fuel distributive highway. The regulator of pressure provides pressure maintenance in fuel system at level of 3.0 atm.

Through electrooperated injectors fuel impulsno is injected into the inlet pipeline located directly ahead of inlet valves of the engine. The control unit the engine makes consecutive management of injectors according to ignition order, regulates injection time and by that amount of injected fuel.

The air necessary for formation of a fuel mix, is sucked in by the engine via the air filter and arrives through a butterfly valve, the air distributor and the inlet pipeline to inlet valves. The amount of soaked-up air is regulated by a butterfly valve given by a cable from a pedal of gas. The volume of soaked-up air is defined by the sensor of an air stream (MAF). For increase in engine capacity the turbokompressor given by a stream of final gases is established.

The control unit determines by the engine optimum time of ignition, the moment of injection and amount of injected fuel in coordination with other systems of the car.

Information from other sensors and the operating tension arriving to executive bodies, provides optimum operation of the engine in any situation. If some sensors fail, the control unit is switched in a mode of the emergency program to exclude possible damage of the engine and to provide further movement of the car.

The arrangement of components of control systems is specified by petrol engines on illustrations.

Arrangement of components of a control system of the 4-cylinder engine

1 — the Sensor of provision of a pedal of gas (APP)
2 — the Sensor of provision of a pedal of a brake (BPP) – on a pedal тормоза*
3 — the Sensor of provision of a cranked shaft (CKP)
4 — the Diagnostic socket (DLC) – under the dashboard, from outside водителя*
5 — the Control unit the engine (ECM) – models with left рулём
6 — the Control unit the engine (ECM) – models with right рулём
7 — the engine management Relay – in assembly in салоне*
8 — the Sensor of temperature of OZh (ECT)
9 — the Valve of 1 purge of an adsorber of EVAP system
10 — the Valve of 2 purges of an adsorber of EVAP system – for a loker of the right lobby wheel арки*
11 — the pressure Sensor паров EVAP systems – in fuel баке*
12 — the Fuel filter – behind, in right bottom углу*
13 — the Regulator of pressure of fuel
14 — the Fuel pump – in fuel баке*
15 — the Relay of the fuel pump – in the assembly block in салоне*
16 — the Lambda probe 1 – before catalytic преобразователем*

17 — the Lambda probe 2 – behind the catalytic converter (models with two lambda probes) *
18 — the ignition Coil – in the module зажигания*
19 — the ignition Module
20 — Injectors
21 — the Sensor of temperature of soaked-up air (IAT)
22 — the detonation Sensor – in the module зажигания*
23 — Ø/m the valve of emergency operation
24 — the Relay Ý/m the valve of emergency operation – in the assembly block in салоне*
25 — the pressure Sensor in the inlet pipeline (MAP)
26 — the Sensor of volume of soaked-up air (MAF)
27 — Э / the motor of a drive of a butterfly valve
28 — the Sensor of provision of a drive of a butterfly valve
29 — Perepuskna капан a turbokompressor
30 — the pressure Sensor in a turbokompressor
31 — the Valve of adjustment of target port of a turbokompressor
32 — the Sensor of speed of the car (VSS, forward right) – on a rotary fist of a wheel

* On an illustration are not designated

Arrangement of components of a control system of the V6 engine

1 — the Sensor of provision of a pedal of gas (APP)
2 — the Sensor of provision of a pedal of a brake (BPP) – on a pedal тормоза*
3 — the Sensor of provision of a pedal of coupling (CPP) – on a pedal сцепления*
4 — the Sensor of provision of a cranked shaft (CKP)
5 — Д/В темпостата (on a brake pedal) *
6 — the Diagnostic socket (DLC) – under the dashboard, from outside водителя*
7 — the Control unit the engine (ECM) – models with left рулём
8 — the Control unit the engine (ECM) – models with right рулём
9 — the engine management Relay – in the main thing assembly блоке*
10 — the Sensor of temperature of OZh (ECT)
11 — the Valve of 1 purge of an adsorber of EVAP system
12 — the Valve of 2 purges of an adsorber of EVAP system – behind, in the right bottom corner, model since 2000 вып. (VIN since 040000) *
13 — the pressure Sensor паров EVAP systems – in a fuel tank, model since 2000 вып. (VIN since 040000) *
14 — the Fuel filter – behind, in right bottom углу*
15 — the Regulator of pressure of fuel
16 — the Fuel pump – in fuel баке*
17 — the Relay of the fuel pump – in the main thing assembly блоке*
18 — Dokatalitichesky a lambda probe – before catalytic преобразователем*

19 — the Lambda probe 2 – behind the catalytic converter, models since 2000 вып. (VIN since 040000) *
20 — the ignition Coil – in each module зажигания*
21 — the Forward module of ignition
22 — the Back module of ignition
23 — Injectors
24 — the Sensor of temperature of soaked-up air (IAT)
25 — the detonation Sensor – in each module зажигания*
26 Ø/m valve of emergency operation
27 — the Relay Ý/m the valve of emergency operation – in the main thing assembly блоке*
28 — the Sensor of absolute pressure in the inlet pipeline (MAP)
29 — the Sensor of volume of soaked-up air (MAF)
30 — the Pump of a podmeshivaniye of air (SAI), model since 2000 вып. (VIN since 040000)
31 — the Relay of the pump SAI, model since 2000 вып. (VIN since 040000) – in the main thing assembly блоке*
32 — Э / the motor of a drive of a butterfly valve
33 — the Sensor of provision of a drive of a butterfly valve
34 — the Switch of AT modes
35 — the Sensor of speed of the car (VSS, forward right) – on a rotary fist of a wheel

* On an illustration are not designated

The scheme components of a power supply system and release of OG are given in illustrations.

Scheme of an inlet air path and path of release of OG of 4-cylinder engines


1 — the Control valve 2 — the Filtering element 3 — the MAF Sensor 4 — Turbokompressor 5 — Interkuler 6 — Perepuskna the valve 7 — Ø/m the valve 8 — the throttle Case 9 — the Sensor of pressure forced the IAT air/sensor 10 — the MAP Sensor 11 — the Engine 12 — the Oil separator of system of ventilation of a case	13 — Control valves 14 — the purge Valve 15 — an EVAP system Adsorber 16 — the Valve of final port 17 — the Regulator of forced air 18 — the Control valve of forced air 19 — the Lambda probe 20/21 — the Forward/back catalytic converter 22/23 — the Forward/back exhaust silencer 24 — the Vacuum amplifier of brakes 25 — the Servo-driver of brakes 26 — the Control valve

The scheme of supply of fuel of petrol engines on an example of the 4-cylinder engine


1 — the Fuel tank 2 — the Fuel pump 3 — the Fuel filter 4 — the Submitting fuel line	5 — the Fuel distributive highway 6 — the Injector 7 — a pressure Regulator 8 — the Returnable fuel line

Short description of principles of functioning of some of sensors and actuation mechanisms of a control system of the engine

The sensor of provision of a butterfly valve (TPS) is built in in the executive mechanism of a butterfly valve and issues on ECM information on the current coal of provision of a butterfly valve. The second potentiometer reports ECM data on base value and forms a spare signal at failure of a potentiometer of a butterfly valve.

The sensor of provision of a cranked shaft (CKP) hands over to the control unit information on number of turns of a cranked shaft and finding of the piston of the first cylinder in VMT.

The sensor of temperature of cooling liquid (ECT) represents the resistor with the negative temperature factor which resistance decreases with temperature growth.

The sensor of measurement of weight of air (MAF) represents the termoanemometrichesky measuring instrument which has been built in in an inlet air path of the engine, and ECM is used at determination of parameters of a dosage of an air and fuel mix.

The system of ventilation of fuel tank/catching of fuel evaporations (EVAP) consists of a coal adsorber and Ý/m the valve of management of a purge of the last. In an adsorber pairs of fuel which are forming as a result of its heating accumulate. At operation of the engine the fuel evaporations which have accumulated in an adsorber are extended to the inlet highway and go to combustion chambers.

Lambda probes measure the content of oxygen in the fulfilled gases (OG) before and after catalytic converters and transmit the corresponding signals in the control unit the engine.