This section only briefly describes injection system faults caused by failure of certain sensors. The procedure for removing and installing fuel supply and engine control system units is given in the subsections "Fuel Supply System", p. 127 and "Engine Control System", p. 225.
In the feedback injection system, a catalytic converter of exhaust gases and a sensor of oxygen concentration in exhaust gases are installed, which provides feedback. The sensor monitors the concentration of oxygen in exhaust gases, and the electronic control unit, using its signals, maintains such a ratio of air and fuel at which the converter operates most effectively.
WARNING: Before removing any fuel injection system components, disconnect the negative battery cable.
WARNING: Disconnect the battery only when the ignition is off.
WARNING: Do not start the engine if the battery cable terminals are not tight.
WARNING: Never disconnect the battery from the vehicle's electrical system while the engine is running.
WARNING: When charging, disconnect the battery from the vehicle's electrical system, as the increased charging current may damage the electronic components.
WARNING: Do not allow the electronic control unit (ECU) to heat up above 65°C when in operation or above 80°C when not in operation (e.g. in a drying chamber). The ECU must be removed from the vehicle if this temperature is exceeded.
WARNING: Do not disconnect or connect the wiring harness connectors to the ECU with the ignition on.
WARNING: Before performing arc welding on a vehicle, disconnect the battery cables and the ECU cable connectors.
WARNING: Make all voltage measurements with a digital voltmeter with an internal resistance of at least 10 megohms.
WARNING: The electronic components used in the injection system are designed for very low voltage and can therefore be easily damaged by electrostatic discharge. To prevent damage to the ECU by electrostatic discharge: – do not touch the ECU connectors or electronic components on its boards with your hands; – when working with the programmable read-only memory (PROM) of the control unit, do not touch the microcircuit terminals.
WARNING: Do not operate an engine with a catalytic converter on leaded gasoline - this will lead to rapid failure of the catalytic converter and oxygen concentration sensor.
WARNING: When operating in rainy weather, do not allow water to come into contact with the electronic components of the fuel injection system.
The vast majority of fuel injection system faults are caused by 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;.
- absolute pressure (vacuum) sensor in the intake manifold - increased fuel consumption, significant deterioration in dynamics, problems with starting the engine;.
- throttle position sensor - loss of power, jerks and dips during acceleration, unstable operation in idle mode;.
- coolant temperature sensor (installed on the right side of the cylinder head under the intake pipe, the intake pipe support bracket has been removed for clarity) - difficulties starting in cold weather: you have to warm up the engine, maintaining the speed with the accelerator pedal, when overheating, the power is significantly reduced, detonation appears;.
– intake air temperature sensor – increased fuel consumption, increased exhaust gas toxicity;.
– oxygen concentration sensor (lambda probe) – increased fuel consumption, decreased engine power, unstable idling. Possible damage to the catalytic converter of exhaust gases;.
- electromagnetic valve of the variable valve timing system (installed only on 1.6 engines); 2.3 and 2.5 l VCT – if the valve fails, there is a significant deterioration in dynamics and "floating" of the crankshaft speed in idle mode up to a complete engine stop;.
- knock sensor (installed on the right side of the cylinder block in the area of the 2nd and 3rd cylinders) - the engine is very sensitive to the quality of gasoline, increased tendency to detonation;.
- speed sensor (installed on the gearbox housing) - possible deterioration of the vehicle's dynamic qualities and increase in fuel consumption;.
- electromagnetic valves…
…and pneumatic drives of the intake manifold geometry change system – the dynamic qualities of the car may deteriorate and fuel consumption may increase.