Fig. 8.0. Zetec-SE engine intake tract: 1 – intake camshaft; 2 – nozzle; 3 – inlet channel; 4 – spark plug
Petrol engines with fuel injection are quite powerful and at the same time economical engines. With the same fuel quality, fuel injection allows a slight increase in compression, in addition, electronic fuel dosing is carried out more accurately than in an engine with a carburetor. All this reduces fuel consumption, increases engine power and reduces the toxicity of exhaust gases. Fiesta cars are no exception: since 1996, Ford has been installing exclusively electronically controlled injection systems with programmed injection characteristics, ignition control and ignition timing adjustment on its engines, which ensure the preparation of a homogeneous fuel-air mixture in the intake tract by spraying fuel from four injectors. Systems such as fuel injection and ignition cease to be independent and become components of integral engine management systems.
Fig. 8.1. Schematic diagram of the fuel injection system of the Zetec-SE engine: 1 – battery; 2 – tank with activated carbon; 3 – Evaporative emission control system electromagnetic valve EAVAP; 4 – electronic ignition coil (El); 5 – nozzle; 6 – Engine Air Temperature (IAT) sensor; 7 – Throttle position sensor (TP); 8 – fuel distribution line; 9 – fuel pressure regulator; 10 – fuel pump; 11 – fuel filter; 12 – Battery Fuse Switch (IFS); 13 – Fuel pump relay (FPR); 14 – Engine idling crankshaft speed control valve (IAC); 15 – vacuum regulator of the exhaust gas recirculation system EGR (EVR); 16 – to the intake manifold; 17 – EGR exhaust gas recirculation valve; 18 – pressure difference measurement point; 19 – electronic differential pressure transducer (DPFE sensor); 20 – Air flow meter (MAP); 21 – Air filter housing and sound-absorbing pipe; 22 – Diagnostic Connector (DLC); 23 – from the octane corrector service connector (OAI); 24 – Air conditioning compressor clutch; 25 – VEEC control unit; 26 – Air conditioning fan switch; 27 – Engine Start Interlock (PATS); 28 – Power steering switch (PSP); 29 – ignition switch with anti-theft device; 30 – power relay; 31 – Crankshaft Position Sensor (CKP); 32 – Coolant Temperature Sensor (ECT); 33 – oxygen sensor (HO2S); 34 – Camshaft Position Sensor (CMP)
Fuel injection system control units are completely maintenance-free; possible failures and malfunctions can be eliminated only with comprehensive specialized knowledge and equipment. Therefore, repair and maintenance of the Fiesta injection system should only be carried out at a service station. However, it is necessary to know the basic criteria for preparing the fuel-air mixture in order to more accurately determine a possible malfunction and save money on expensive diagnostics. Below, we consider the Ford injection system installed on Zetec-SE engines (Fig. 8.1).