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The engine management system MFI
Placing control elements MFI 1 - air flow meter "OBD";
2 - the temperature sensor in the engine air inlet;
3 - Meter air except "OBD";
4 - fuel ratio sensor than "OBD";
5 - coolant temperature sensor;
6 - throttle position sensor;
7 - the camshaft position sensor;
8 - sensor crankshaft angle;
9 - heated oxygen sensor;
10 - the fuel injectors;
11 - Modulator frequency of idling;
12 - the gauge of speed of the car; | 13 - the gauge of detonation;
14 - the switch of ranges of a transmission;
15 - the ignition lock;
16 - ECM engine control unit;
17 - the relay of the air conditioning system;
18 - the electromagnetic valve of clearing of the canister with the activated carbon;
19 - main relay MFI;
20 - the ignition coil;
21 - the fuel pump;
22 - acceleration sensor;
23 - Diagnostic connector. |
Management of the fuel system performed ECU ECM (Engine Control Module). ECM conducts adjustment of the ignition timing, determines the amount of fuel supplied to the engine, the system controls the emission control and speed of the crankshaft of the engine idling and the air conditioning compressor clutch, etc. The ECM changes the modes of operation of the engine according to the varying operating conditions on the basis of signals from various switches and sensors.
For example, the ECM adjusts the ignition timing based on the sensor signals, which are responsive to the engine speed, coolant temperature, throttle position, is currently included in the transmission, vehicle speed, etc.
The ECM controls the engine speed of idling on the basis of the sensor signals that are responsive to throttle position, vehicle speed, currently included in the transfer, etc. Air flow meter sensor "OBD" (MAF - Mass Airflow Sensor)
Meter of air provides the most direct method to measure the load of the engine, as it measures the amount of air entering the engine. Feed air enters the engine through the meter with a hot and cold wire elements forming part of a bridge circuit. The current passing through the heated wire member maintains constant its temperature at a constant level, which is higher than the temperature of air entering the engine. Air mass is determined by the strength of current required to maintain the temperature of the wire element. The greater the air flow, and naturally cooling thereof, the greater the value of the signal applied to the ECM.
The gauge of temperature of air entering the engine "OBD" (IAT - intake air temperature)
The temperature sensor of air entering the engine is a thermistor whose resistance varies with temperature. The ECM allows for the sensor signal and adjusts the pulse width supplied to the nozzle, thereby changing the amount of fuel supplied to the engine cylinders, and the ignition timing changes.
Check sensor
| PERFORMANCE ORDER | | 1. Measure the voltage between terminals 1 and 3 of the sensor connector. | Temperature | Output voltage | 0 ?� C | In 3.3-3.7 | 20 ?� C | In 2.4-2.8 | 40 ?� C | In 1.6-2.0 | 80 ?� C | In 0.5-0.9 |
| | 2. If the sensor output voltage is not correct, replace the sensor. |
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The gauge of absolute pressure in an inlet collector, except "OBD" (MAF - Manifold Absolute Pressure)
The gauge of absolute pressure in the intake manifold is a sensitive variable resistor. It measures the pressure in the intake manifold which varies depending on operating conditions of the engine and is converted into a voltage. The sensor is also used to measure atmospheric pressure at engine start and ensures operating conditions of the engine at different altitudes above sea level. Based on information from the sensor ECU regulates the amount of fuel supplied to the engine, and changes the ignition timing.
Check
| PERFORMANCE ORDER | | 1. Measure the voltage between terminals 1 and 4 of the sensor connector. Output voltage with the ignition on and engine stopped: 4-5 In
The output voltage at a frequency of idling: 0.5-2.0 In | | 2. If the sensor output voltage is not correct, replace the sensor. |
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The gauge of temperature of air entering the engine (IAT - intake air temperature)
The temperature sensor of air entering the engine is a thermistor whose resistance varies with temperature. The ECM allows for the sensor signal and adjusts the pulse width supplied to the nozzle, thereby changing the amount of fuel supplied to the engine cylinders, and the ignition timing changes.
Check
| PERFORMANCE ORDER | | 1. Measure the resistance between terminals 1 and 2 of the sensor connector. | Temperature | Resistance | 0 ?� C | 4.5-7.5 Ohm | 20 ?� C | 2.0-3.0 Ohm | 40 ?� C | 0.7-1.6 Ohm | 80 ?� C | 0.2-0.4 Ohm |
| | 2. If the sensor resistance is not correct, replace the sensor. |
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The coolant temperature sensor (ECT - Engine Coolant temperature)
The coolant temperature sensor monitors the temperature of the coolant and on the basis of the sensor signal, the ECM calculates the width of the pulse supplied to the nozzle, thereby changing the amount of fuel supplied to the engine cylinders, and the ignition timing changes.
On a cold engine, the ECM operates in open loop, causing the engine cylinders supplied toplivnovozdushnaya richer mix and increased idle speed. This continues until the motor has reached its normal operating temperature.
Withdrawal
| PERFORMANCE ORDER | | 1. Remove the gauge from the engine. |  | 2. heating the vessel with water and placed it in tow, check its resistance. | Temperature | Resistance | -30 ?� C | 22,22-31,78 kW | -10 ?� C | 8,16-10,74 kW | 0 ?� C | 5,18-6,60 Ohm | 20 ?� C | 2,27-2,73 Ohm | 60 ?� C | 1,059-1,281 kW | 40 ?� C | 0,538-0,650 kW | 80 ?� C | 0,298-0,322 kW | 90 ?� C | 0,219-0,243 kW |
| | 3. If the sensor resistance is not correct, replace the sensor. |
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Setting
| PERFORMANCE ORDER | | 1. Apply sealant to the threads of the sensor LOCTITE 962T. | | 2. Screw the sensor into the engine block and tighten its demanded moment. Torque: 15-20 N ??? m | | 3. Connect the sensor electrical connector. |
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Throttle position (TP - Throttle Position)
Throttle position sensor transmits the information upon which the ECM determines when the throttle is closed, fully open or in intermediate positions. The sensor is rigidly connected to the throttle shaft. Depending on the throttle position sensor resistance changes. To power the transmitter with ECM for the unit 5 V output voltage of the sensor is changed from 0.25 V at minimum throttle to 4.7 V at full throttle.
Check
| PERFORMANCE ORDER | | 1. Unplug the connector from the throttle position sensor. |  | 2. Measure the resistance between terminals 1 and 2 of the sensor connector. Resistance: 0,7-3,0 clod | | 3. Connect an ohmmeter to terminals 1 and 3 of the sensor connector. | | 4. Slowly open the throttle and check that the resistance of the sensor changes smoothly in proportion to the throttle. | | 5. If the sensor resistance is not correct, or change abruptly, replace the sensor. Tightening torque: 1.5-2.5 N ??? m |
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Camshaft position sensor (CMP - Camshaft Position Sensor)
Camshaft position sensor generates pulses based on which the ECM identifies the first cylinder and the opening of the nozzle.
Sensor crank angle (CKP - Crankshaft Position Sensor)
Sensor crank angle passes the ECM information about the position of the crankshaft. Based on the information of the output signal of the sensor and the signal of the camshaft sensor, the ECM detects the ignition timing and the cylinder, which must be supplied with fuel. In the absence of the sensor output signals the engine starts.
Check
| PERFORMANCE ORDER | | 1. Unplug the connector from the sensor crank angle |  | 2. Measure the resistance between terminals 1 and 2 of the sensor connector. Resistance: 0,486-0,594 ohms at 20 ?� C | | 3. If the sensor resistance is not correct, replace the sensor. The gap between the rotor and the sensor crank angle: 0.5-1.0 mm
Torque: 9-11 N ??? m |
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The oxygen sensor
Depending on the oxygen concentration in the exhaust gas oxygen sensor induces a voltage from 0 to 1 V. On the basis of these data, the engine control unit changes the opening of the injectors and the fuel ratio in toplivnovozdushnoy mixture. In order to complete combustion of the combustible mixture and the exhaust gases no harmful substance, 14.7 parts by weight of the air shall have to 1 part of fuel.
The oxygen sensor is equipped with a heater that maintains a temperature sensor within a certain range when the engine under all operating conditions. Maintaining a specific temperature sensor enables the system to quickly engage in work and to work in an idling mode.
Check
| PERFORMANCE ORDER |
A warning  Before testing the engine to warm up until the coolant temperature is equal to 80-95 ?� C.
Accurate digital voltmeter to measure the output voltage of the sensor.
| | If the sensor output voltage is not correct, replace the sensor. Torque: 50-60 N ??? m |
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Fuel injectors
The fuel injector based on the signals from the ECM inject fuel into the engine cylinders. Fuel flow depends on the opening time of the injectors, i.e. the width of the voltage pulse to the winding nozzle.
Check
| PERFORMANCE ORDER |  | 1. When the engine is idling or stethoscope thumb check the operation of the nozzles by the presence of clicks. | | 2. If there are no clicks, check the connection of the connectors to the injectors and the output voltage of the control unit. |  | 3. Disconnect the connector from the fuel injector and measure the resistance between the contacts of the connector.
Resistance: 15,9 ?� 0,35 Ohm | | 4. Connect to the fuel injector. |
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Knock sensor
Knock sensor responds to high-frequency vibrations of the cylinder, and converts them into electrical signals, the magnitude of which increases with increasing the detonation. Based on these signals, the ECM displaces the ignition timing to the delay side, thereby eliminating detonation. Fuel pipes and hoses
Fuel pipes and hoses allow the transfer of fuel from the fuel tank to the fuel lines and injectors and return excess fuel to the tank. Fuel lines attached to the bottom of the car, must be periodically inspected for dents and deformation as due to narrowing of the passages may be restricted fuel flow.
Fuel pipes and hoses also ensure the transfer of fuel vapors from the fuel tank to the canister with the activated coal, where they are going with the engine off. After engine start-up and warm up to operating temperature the engine control unit opens the solenoid valve and the fuel vapor from the canister into the engine and burned.
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