Chapter 1 Routine maintenance and servicing

Fuel system – carburettor engines 4A•31 General information andprecautionsGeneral informationThe fuel system on all models withcarburettor induction comprises a rearmountedfuel tank, a mechanical diaphragmfuel pump, a carburettor and an air cleaner.The fuel tank is mounted at the rear, underthe floorpan behind the rear seats. The tankhas a “ventilation-to-atmosphere system”through a combined roll-over/anti-trickle fillvalve assembly, located in the left-hand rearwheel arch. A filler neck sensing pipe, integralwith the fuel tank filler pipe, will shut off thepetrol pump filler gun when the predeterminedmaximum level of fuel is reached in the tank,so preventing spillage and wastage. Aconventional fuel level sender unit is mountedin the top face of the fuel tank.One of two fuel pump types will be fitted,depending on the engine type. On HCSengines, the fuel pump is operated by apivoting rocker arm; one end rests on aneccentric lobe on the engine camshaft, andthe other end is attached to the fuel pumpdiaphragm. The pump fitted to the CVHengine is operated by a separate pushrod,one end rests on an eccentric lobe on theengine camshaft, and the other rests on thepump actuating rod which operates thediaphragm. Both types of mechanical pumpincorporate a nylon mesh filter, and are ofsealed type (they cannot be serviced oroverhauled).Four different types of Weber carburettorare featured in the range, further details beinggiven in later Sections of this Chapter.The air cleaner incorporates a “waxstat”controlled air inlet, supplying either hot airfrom a shroud mounted around the exhaustmanifold, or cool air from a duct in the front ofthe vehicle.PrecautionsWarning: Petrol is extremelyflammable - great care must betaken when working on any partof the fuel system. Do not smoke or allowany naked flames or uncovered light bulbsnear the work area. Note that gas powereddomestic appliances with pilot flames,such as heaters, boilers and tumbledryers, also present a fire hazard - bearthis in mind if you are working in an areawhere such appliances are present.Always keep a suitable fire extinguisherclose to the work area and familiariseyourself with its operation before startingwork. Wear eye protection when workingon fuel systems and wash off any fuel spilton bare skin immediately with soap andwater. Note that fuel vapour is just asdangerous as liquid fuel; a vessel that hasjust been emptied of liquid fuel will stillcontain vapour and can be potentiallyexplosive. Petrol is a highly dangerous andvolatile liquid, and the precautionsnecessary when handling it cannot beoverstressed.Many of the operations described in thisChapter involve the disconnection of fuellines, which may cause an amount of fuelspillage. Before commencing work, referto the above Warning and the informationin “Safety first” at the beginning of thismanual.When working with fuel systemcomponents, pay particular attention tocleanliness - dirt entering the fuel systemmay cause blockages which will lead topoor running.Certain adjustment points in the fuel systemare protected by tamperproof caps, plugs orseals. In some territories, it is an offence todrive a vehicle with broken or missingtamperproof seals. Before disturbing atamperproof seal, first check that no local ornational laws will be broken by doing so, andfit a new tamperproof seal after adjustment iscomplete, where required by law. Do notbreak tamperproof seals on any vehicle whilstit is still under warranty.Carburettors are delicate instruments, andcare must be taken not to disturb anycomponents unnecessarily. Before attemptingwork on a carburettor, ensure that the relevantspares are available; it should be noted that acomplete strip down of a carburettor isunlikely to cure a fault which is notimmediately obvious, without introducing newproblems. If persistent problems occur, it isrecommended that the services of a Forddealer or a carburettor specialist are sought.Most dealers will be able to providecarburettor rejetting and servicing facilities.Where necessary, it may be possible topurchase a reconditioned carburettor.2 Air cleaner -removal and refitting1Note: Air cleaner element renewal and aircleaner temperature control system checksare described in Chapter 1.Removal1 Disconnect the battery negative (earth) lead(refer to Chapter 5A, Section 1).2 On CVH engine models, pull free andrelease the accelerator cable from the locatingclip on the side of the air cleaner.3 Undo the two (HCS engine) or three (CVHengine) retaining screws, and partially lift theair cleaner from the carburettor so that thehose and wiring connections to the undersideof the air cleaner body are accessible (seeillustration).4 Note their connections and routings, thendetach the wiring multi-plug and hoses fromthe underside of the air cleaner (seeillustrations). On CVH engines, alsodisconnect the vacuum hose from the inletmanifold.5 Lift the air cleaner from the carburettor.6 If required, the inlet air temperature sensorcan be unscrewed and removed from thebase of the air cleaner (where fitted).Refitting7 Refit in the reverse order of removal. Renewany hoses that are perished or cracked, andensure that all fittings are securely andcorrectly reconnected.4A2.3 Undoing the air cleaner retainingscrews (HCS engine shown)2.4a Disconnecting the oil separator/crankcase ventilation hose from the aircleaner (CVH engine shown)2.4b Disconnecting the intake airtemperature sensor multi-plug(CVH engine shown)1595Ford Fiesta Remake