ZEST BOLT Service Manual

ENGINE 1.3 QUADRAJET (75PS) I. CONTROL OF AMOUNT OF FUEL INJECTED On the basis of the signals coming from the sensors and the values stored, the control unit : Q controls the pressure regulator on the rail; Q controls the regulator on the pressure pump to modulate the fuel flow rate (for the 90 CV version only) Q varies the "pilot" injection time in the entire rpm range; Q alters the "main" injection time. J. IDLE SPEED CHECK The control unit processes the signals coming from the sensors and regulates the quantity of fuel injected: Q controls the pressure regulator; Q alters the injector injection times. Within certain limits the speed takes the battery voltage into account. K. FUEL CUT-OFF DURING DECELERATION During the accelerator pedal release st age, the control unit implements the following logics : Q places the injector opening time at zero; Q partly varies the injection time for the injectors before the idle speed is reached; Q controls the fuel pressure regulator. L. IDLE CYLINDER BALANCE CHECK According to the signals received from the sensors, the control unit controls the idle speed torque : Q alters the quantity of fuel injected by the individual injectors (injection time). M. CHECK ON IRREGULAR OPERATION The control unit processes the signals received by the various sensors and corrects the quantity of fuel to inject in order to improve driveability reducing shuddering whilst driving by means of the injector opening time. N. EXHAUST FUMES CONTROL DURING ACCELERATION In order to restrict the fumes during fast transitions, on the basis of the signals received from the accelerator pedal potentiometer, Lambda sensor, flow meter and the engine speed the control unit limits the amount of fuel to be injected by means of : Q the pressure regulator Q the injection time for the injectors. Q E.G.R. O. EXHAUST GAS RECIRCULATION CONTROL (E.G.R.) In accordance with EURO 4 pollution control legislation, on the basis of the engine load and the signal from the accelerator pedal potentiometer, the control unit limits the quantity of intake air, implementing the p artial intake of exhaust gases, through : Q the adjustment of the opening of the E.G.R. valve P. MAXIMUM TORQUE LIMIT CONTROL According to the rpm level, the control unit calculates the following in pre-defined maps : Q the torque limit; Q the permitted fumes (limit). It compares this minimum values and correct s them with other parameters : Q coolant temperature; Q engine rpm; Q vehicle speed; Q air temperature. and controls the quantity of fuel to be injected (pressure regulator - injectors). Q. MAXIMUM SPEED LIMIT CONTROL When the engine speed reaches 5200 rpm, the control unit interrupts the operation of the injectors and the supply pressure is consequently reduced. R. HEATER PLUGS CHECK The injection unit, during the following stages : Q starting; Q post-starting; Q applies a timer to the glow plug preheating control unit based on engine temperature. 100