Chapter 1 Routine maintenance and servicing

1595Ford Fiesta Remake4C•2 Fuel system - electronic fuel injection enginesTorque wrench settings Nm lbf ftIdle speed control valve bolts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 to 5 3 to 4Fuel pressure regulator bolts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 to 12 6 to 9Fuel rail bolts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 to 26 15 to 19Inlet air temperature sensor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 to 25 15 to 18Inlet manifold . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 to 20 12 to 15Oxygen sensor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50 to 70 37 to 52Intercooler-to-radiator bolts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 to 6 3 to 5Boost control valve screws . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.2 to 2.7 1.5 to 2Exhaust manifold heatshield bolts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 to 26 16 to 19Exhaust manifold-to-engine nuts (non-Turbo models) . . . . . . . . . . . . . . 14 to 17 11 to 13Exhaust manifold-to-engine nuts (Turbo models) . . . . . . . . . . . . . . . . . 28 to 31 21 to 23Exhaust manifold-to-turbocharger bolts . . . . . . . . . . . . . . . . . . . . . . . . 20 to 28 15 to 21Turbocharger-to-exhaust downpipe nuts . . . . . . . . . . . . . . . . . . . . . . . . 35 to 47 26 to 35Turbocharger cooling pipe banjo union bolts . . . . . . . . . . . . . . . . . . . . . 22 to 29 17 to 22Turbocharger oil feed and return line couplings . . . . . . . . . . . . . . . . . . . 15 to 20 11 to 151 General information andprecautionsGeneral informationThe fuel system consists of a fuel tank(mounted under the body, beneath the rearseats), fuel hoses, an electric fuel pumpmounted in the fuel tank, and an electronicfuel injection system.Fuel is supplied under pressure from thefuel pump to the fuel distributor rail mountedon top of the inlet manifold (see illustration).The fuel rail acts as a pressurised fuelreservoir for the fuel injectors. The electromechanicalinjectors have only “on” or “off”positions, the volume of fuel being injected tomeet the engine operating conditions beingdetermined by the length of time that theinjectors are opened. The volume of fuelrequired for one power stroke is determinedby the EEC IV engine management module,and is divided by two equal amounts. The firsthalf of the required volume is injected into thestatic air ahead of the inlet valve one completeengine revolution before the inlet valve is dueto open. After one further revolution, the inletvalve opens and the required fuel volume isinjected into the air flow being drawn into thecylinder. The fuel will therefore be consistentlyinjected to two inlet valves simultaneously at aparticular crankshaft position.The volume of air drawn into the engine isgoverned by the air filter unit and othervariable operating factors. These variables areassessed by the EEC IV module and the1.2 General view of the 1.6 litre EFi fuel injection system arrangement1 Throttle housing2 Upper inlet manifold section3 Wiring loom connector4 Intake air temperaturesensor5 Wiring harness ducting6 Fuel rail7 Lower section of inletmanifold8 Cylinder head9 Fuel injector10 Fuel pressure regulator11 Vacuum hose12 Air inlet ductcorresponding signals are produced toactuate the injectors accordingly.The engine base idle speed can beadjusted (if required), by turning the adjusterscrew (covered by a tamperproof cap) in thethrottle housing. Provision for adjusting thefuel mixture is made by the mixture screw inthe potentiometer unit mounted on thebulkhead.An idle speed control valve, itself controlledby the EEC-IV engine management module,stabilises the engine idle speed under allconditions by the opening of an auxiliary airpassage which bypasses the throttle. Apartfrom a base-idle speed adjustment, noadjustments to the operational idle speed canbe made.The EEC IV module is the heart of the entireengine management system, controlling thefuel injection, ignition and emissions controlsystems. The module receives informationfrom various sensors to determine enginetemperature, speed and load, and thequantity of air entering the engine. Thesensors also inform the module of throttleposition, inlet air temperature and, on modelswith catalytic converters, exhaust gas oxygencontent. All the information supplied to themodule is computed and compared withpre-set values stored in it’s memory, todetermine the required period of injection.Information on crankshaft position andengine speed is generated by a crankshaftposition sensor. The inductive head of thesensor runs just above the engine flywheeland scans a series of 36 protrusions on theflywheel periphery. As the crankshaftrotates, the sensor transmits a pulse to thesystem’s ignition module every time aprotrusion passes it. There is one missingprotrusion in the flywheel periphery at a pointcorresponding to 90° BTDC. The ignitionmodule recognises the absence of a pulsefrom the crankshaft position sensor at thispoint to establish a reference mark forcrankshaft position. Similarly, the time intervalbetween absent pulses is used to determineengine speed. This information is then fed tothe EEC IV module for further processing.