This description is from a 1985 model 2.2L. It's the closest I have. Generally this model year vehicle is not fitted with an immoboliser unless it is aftermarket. I would need the VIN/Engine number to research the exact engine system you have installed. It should be basically the same as below with maybe some minor changes !
The Bosch Airflow Controlled (AFC) fuel injection system is an electronically-controlled system, operated by incoming airflow. The AFC fuel injection system also contains a feedback system which measures oxygen content of exhaust gases. It uses this information to maintain the air/fuel ratio at approximately 14.7:1.
The fuel injection system consists of an electric fuel pump, fuel pressure regulator, fuel injectors, Electronic Control Unit (ECU), airflow meter, air temperature sensor, throttle switch, coolant temperature switch, oxygen sensor, catalytic converter and electrical relays.
All models are equipped with a cold start system to aid in cold engine starts. The cold start system consists of an auxiliary air valve, cold start injector and thermo time switch. A/C equipped Renault models use an A/C solenoid valve to provide additional air when the compressor is activated.
ELECTRIC FUEL PUMP
The fuel pump provides fuel under pressure to the fuel pressure regulator. Power for operation during cranking mode is provided from starter relay via the fuel pump relay. After the engine has started, control of the fuel pump is by a fuel pump circuit in the airflow meter.
The first movement of the airflow meter air measuring flap (about 5 ) closes the fuel pump contacts and provides power to fuel pump after engine has started. With engine stopped, no airflow is present, measuring flap closes and fuel pump contacts are opened to cut power to fuel pump. This circuit reduces the risk of fire in a collision. The fuel pump is a sealed unit. No service is required.
FUEL PRESSURE REGULATOR
The pressure regulator consists of a sealed, spring-loaded diaphragm with a connection for intake manifold vacuum. Fuel is provided to fuel injectors under approximately 36 psi (2.5 kg/cm2 ) pressure.
A connection for intake manifold vacuum provides a constant pressure differential which ensures that the amount of fuel injected is solely dependent upon injector "open" time. Excess fuel is returned to fuel tank. No service of pressure regulator is required.
Fig. 1: Fuego and Sportwagon AFC Fuel Injection System
A fuel rail links the fuel pressure regulator with the fuel injectors. Each cylinder is provided with a solenoid-operated injector which sprays fuel toward the back of each inlet valve. Each injector is energized through the ignition coil and grounded through the ECU to complete the circuit.
Each injector is linked to a resistor (resistor may be external or integral with injector or ECU) to reduce operating voltage to 3 volts and to protect injectors from power surges. The ECU controls the length of time each injector is open.
The "open" time of the injector governs the amount of fuel delivered. The injectors deliver 1/2 the amount of fuel required for an operating cycle each time they open (twice per cycle).
ELECTRONIC CONTROL UNIT (ECU)
All components of the control system are electrically connected to the ECU. See Fig. 2. The ECU is a preprogrammed computer that receives and interprets data from various sensors. It calculates the amount of fuel required by the engine to maintain efficiency with minimum exhaust emissions.
Impulses from the oxygen sensor inform the ECU of oxygen content of exhaust gases and the ECU constantly adjusts the air/fuel ratio by controlling the injector "open" time.
The ECU provides fuel enrichment whenever engine is cranked, regardless of engine temperature. This is activated by a direct electrical connection from the starter circuit to the ECU. The ECU is a sealed unit. No service is required.
Fig. 2: Electronic Control Unit (ECU)
All engine air is drawn through the airflow meter. The meter contains a tunnel with measuring flap and dampening flap (offset 90 on same casting). The measuring flap swings in air stream against pressure of a spiral spring and is connected to a potentiometer.
The potentiometer transmits an electrical signal determined by measuring flap position to inform the ECU of engine load. See Fig. 3. In addition to monitoring the airflow, the meter also controls fuel pump operation and idling. At idle, the measuring flap is almost closed due to spiral spring pressure.
The potentiometer within the airflow meter prevents loss of engine power during sudden acceleration/deceleration by signaling the ECU of necessary fuel enrichment requirements.
An idle air by-pass receives air from main airflow through a small hole, the size of which is controlled by the idle mixture screw. This adjustable air by-pass influences CO levels at low engine speeds.
Fig. 3: Bosch AFC Airflow Meter
AIR TEMPERATURE SENSOR
The air temperature sensor is part of airflow meter. It converts the temperature of incoming air into electrical signals. These signals are received by the ECU and used to adjust the amount of fuel injected. The air temperature sensor is a non-serviceable device.
A contact-type throttle switch is installed on the throttle chamber of all models. It converts throttle position into electrical signals to inform ECU of throttle position. See Fig. 4.
Fig. 4: Contact-Type Throttle Switch
COOLANT TEMPERATURE SENSOR
This sensor provides ECU with engine temperature information relating to warm-up enrichment operation. During warm-up period after a cold engine start, additional fuel is required to maintain engine performance. As engine temperature increases, the ECU decreases fuel enrichment until normal operating temperature is reached.
The main relay activates the ECU, injector circuit and starting circuit when ignition is switched to start mode. The fuel pump relay activates the fuel pump during the start mode and is then controlled by airflow during operating mode. Some models incorporate all relays within a single relay set or dual relay. The cold start system is also activated through the relay set. Relay set is located under passenger seat.
COLD START SYSTEM
The cold start system provides additional air and fuel during cold engine starts. It consists of an auxiliary air valve which provides additional air, cold start injector which delivers additional fuel and a thermo time switch which controls operation. The thermo time switch has a bi-metallic contact surrounded by a heating coil which is energized during engine cranking.
This switch limits cold start system operation to 5-12 seconds during extremely cold engine starts. When engine temperature is above 95 F (35 C), bi-metallic contact breaks ground circuit of cold start injector and cold start enrichment is by-passed.
AUXILIARY AIR VALVE
The auxiliary air valve provides additional air during cold engine starts and warm-up. The valve consists of an electrically heated bi-metallic strip, movable disc and air by-pass channel. The heater coil on the bi-metallic strip is energized by the fuel pump relay.
Control of the valve is based upon engine temperature. The air by-pass channel is open when engine is cold and gradually closes as temperature rises. At predetermined temperatures, air by-pass channel is blocked and additional airflow stops. See Fig. 5.
Fig. 5: Auxiliary Air Valve By-pass channel closes as engine temperature rises.
AIR CONDITIONING SOLENOID VALVE
On vehicles equipped with A/C, a solenoid valve delivers additional air to compensate for drop in idle speed when air conditioner is activated. The solenoid is electrically actuated through the compressor clutch circuit to apply vacuum to a circuit behind throttle plate.
The applied vacuum opens the vacuum diaphragm which opens the additional air circuit. The diameter of the air circuit on manual transmission models is 0.12" (3.0 mm) and 0.14" (3.5 mm) on automatic transmission models. See Fig. 6.
Fig. 6: Renault Air Conditioning Solenoid Valve
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Monday, November 23rd, 2009 AT 10:58 AM