Chapter 1 Routine maintenance and servicing

Fuel system - sequential electronic fuel injection engines 4D•7b) Tighten the screws evenly and securely(but do not overtighten them, or thepotentiometer body will be cracked).Vehicle speed sensor48 The sensor is mounted at the base of thespeedometer drive cable, and is removed withthe speedometer drive pinion. Refer to therelevant Section of Chapter 7A or B, asapplicable.Power steering pressure switch49 Releasing its clip, unplug the switch’selectrical connector, then unscrew the switchfrom the power steering high pressure pipe.Place a wad of rag underneath, to catch anyspilt fluid. If a sealing washer is fitted, renew itif it is worn or damaged.50 Refitting is the reverse of the removalprocedure; tighten the switch securely, thentop-up the fluid reservoir (see “WeeklyChecks”) to replace any fluid lost from thesystem, and bleed out any trapped air (seeChapter 10).Oxygen sensorNote: The sensor is delicate, and will not workif it is dropped or knocked, if its power supplyis disrupted, or if any cleaning materials areused on it.51 Raise and support the front of the vehicleif required to remove the sensor fromunderneath (“see Jacking and vehiclesupport”).52 Release the sensor’s wiring multi-plugfrom its support bracket, and unplug it todisconnect the sensor (see illustration).53 Unscrew the sensor from the exhaustsystem front downpipe; collect the sealingwasher (where fitted).54 On refitting, clean the sealing washer(where fitted) and renew it if it is damaged orworn. Apply a smear of anti-seize compoundto the sensor’s threads, to prevent them fromwelding themselves to the downpipe inservice. Refit the sensor, tightening it to itsspecified torque wrench setting; a slottedsocket will be required to do this. Reconnectthe wiring, and refit the connector plug.15 Inlet manifold -removal and refitting 4Note: Refer to the warning note in Section 1before proceeding.RemovalPTE engines1 The inlet manifold is a two-piece assemblycomprising an upper and lower section boltedtogether.2 Drain the cooling system with reference toChapter 1.3 Relieve the residual pressure in the fuelsystem (see Section 2), and equalise tankpressure by removing the fuel filler cap.Warning: This procedure willmerely relieve the increasedpressure necessary for the engineto run - remember that fuel willstill be present in the system components,and take precautions accordingly beforedisconnecting any of them.4 Disconnect the battery negative (earth) lead(refer to Chapter 5A, Section 1).5 Remove the air inlet components (Section4) and disconnect the accelerator cablefrom the throttle linkage (Section 5).6 Remove the fuel injectors and fuel rail asdescribed in Section 14.7 Noting their locations, disconnect thecoolant, vacuum and breather hoses from themanifold.8 Disconnect the wiring multi-plugs from theengine sensors at the inlet manifold.9 Undo the retaining bolts, and withdraw themanifold from the cylinder head. Note thelocation of the engine lifting bracket and earthlead, where fitted. Remove the gasket.10 With the manifold removed, clean alltraces of the old gasket from the matingsurfaces of the manifold and the cylinderhead.Zetec engines11 Relieve the residual pressure in the fuelsystem (see Section 2), and equalise tankpressure by removing the fuel filler cap.Warning: This procedure willmerely relieve the increasedpressure necessary for theengine to run - remember thatfuel will still be present in the systemcomponents, and take precautionsaccordingly before disconnecting any ofthem.12 Disconnect the battery negative (earth)lead (refer to Chapter 5A, Section 1).13 Remove the air inlet components (Section4) and disconnect the accelerator cablefrom the throttle linkage (Section 5).14 Disconnect the crankcase breather hosefrom the cylinder head cover union.15 Unbolt the upper part of the exhaustmanifold heat shield.16 Remove the two screws securing thewiring “rail” to the top of the manifold - this issimply so that it can be moved as required toreach the manifold bolts (see illustration).4D14.52 Oxygen sensor (A) and wiring multiplug(B) (Zetec engine shown)1 Cylinder headcover2 Heat-insulatingplate/gasket3 Intermediateflange/fuel railassembly4 Gasket5 Inlet manifold6 Intake airtemperaturesensor7 Engine wiringloom8 Bolts15.16 Exploded view of the Zetec engine inlet manifold components1595Ford Fiesta Remake