This section only briefly describes the malfunctions of the injection system caused by the failure of certain sensors. The procedure for removing and installing components of power supply systems and engine control is given in subsections «Engine power system» And «Engine management system».
An exhaust gas catalytic converter and an oxygen concentration sensor in the exhaust gases are installed in the feedback injection system, which provides feedback. The sensor monitors the oxygen concentration in the exhaust gases, and the electronic control unit, using its signals, maintains such a ratio of air and fuel at which the converter works most efficiently.
Warnings
Before removing any components of the fuel injection system, disconnect the wire from the terminal «minus» battery. Disconnect the battery only when the ignition is off.
Do not start the engine if the cable lugs on the battery are loose.
Never disconnect the battery from the vehicle's electrical system while the engine is running.
When charging, disconnect the battery from the car's on-board network, as the increased current during charging can damage the electronic components.
Do not allow the electronic control unit to heat up (ECU) above 65°C in working condition and above 80°C - in non-working condition (e.g. in a drying chamber). It is necessary to remove the computer from the car if this temperature is exceeded.
Do not disconnect or connect the wiring harness connectors to the ECU while the ignition is on.
Before performing arc welding on a vehicle, disconnect the wires from the battery and the wire connectors from the ECU.
Perform all voltage measurements with a digital voltmeter with an internal resistance of at least 10 MΩ. The electronic components used in the injection system are designed for very low voltage, so they can easily be damaged by electrostatic discharge. To prevent damage to the ECU by electrostatic discharge, observe the following:
- do not touch the computer plugs or electronic components on its boards with your hands;
- when working with programmable read-only memory (PROM) control unit, do not touch the microcircuit pins.
It is not allowed to work on leaded gasoline of an engine equipped with a converter - this will lead to a quick failure of the converter and the oxygen concentration sensor.
When working in rainy weather, do not allow water to enter the electronic components of the fuel injection system.
Check the injection system in the following order.
1. Check engine and battery connection with «weight».
2. Check the fuel pump and its fuel filter.
3. Check the fuses and relays for switching on the elements of the injection system.
4. Check up reliability of contacts in blocks with wires of elements of system of injection.
5. Check up sensors of system of injection.
The vast majority of fuel injection system malfunctions are caused by the failure of the following sensors:
- crankshaft position sensor - complete failure of the injection system, the engine does not start;
- phase sensor - power reduction, fuel consumption increase (for convenience, shown with the decorative engine cover removed);
- absolute pressure sensor (rarefaction) in the intake pipe - an increase in fuel consumption, a significant deterioration in dynamics, problems with starting the engine;
- throttle position sensor - loss of power, jerks and dips during acceleration, unstable idling (for convenience, it is shown with the air supply sleeve removed);
- coolant temperature sensor (mounted on the right side of the cylinder head under the intake pipe, the intake pipe support bracket has been removed for clarity) - difficulties with starting in cold weather, since you have to warm up the engine, maintaining the speed with the accelerator pedal, when overheated, the power decreases significantly, detonation appears;
- intake air temperature sensor - an increase in fuel consumption, an increase in the level of toxicity of exhaust gases;
- oxygen concentration sensor (Lambda probe) - increased fuel consumption, reduced engine power, unstable idling. Possible damage to the catalytic converter of exhaust gases;
- knock sensor (installed on the right side of the cylinder block in the region of the 2nd and 3rd cylinders) - the engine is very sensitive to the quality of gasoline, increased tendency to detonation;
- speed sensor (mounted on the gearbox housing) - possible deterioration of the dynamic qualities of the car and an increase in fuel consumption;
- solenoid valve...
...and the pneumatic drive of the system for changing the geometry of the intake pipe - it is possible that the dynamic qualities of the car will deteriorate and fuel consumption will increase.