Fuel cut switch FIAT PUNTO 1998 176 / 1.G Workshop Manual

Safety first! 0.5
Working on your ear can be dangerous. This page shows just some of the potential risks and hazards, with the aim of creating a safety-conscious attitude.
General hazards
Scalding • Don't remove the radiator or expansion tank cap while the engine is hot. • Engine oil, automatic transmission fluid or power steering fluid may also be dangerously hot if the engine has recently been running.
Burning • Beware of burns from the exhau3t system and from any part of the engine. Brake discs and drums can also be extremely hot immediately after use.
Crushing • When working under or near a raised vehicle. ~ always supplement the ' ' -jack with axle stands, or use ... drive-on i'j ramps. kr Never venture ™ under
a
car
vv/j/ch
Is only supported by a jack. • Take card if loosening or tightening high-torque nuts when the vehicle is on stands. Initial loosening and final tightening should be done with the wheels on the ground.
Fire • Fuel Is highly flammable; fuel vapour is explosive. • Don't (et fuel spill onto a hot engine. • Do not smoke or allow naked lights (including pilot lights) anywhere near a vehicle being worked on. Also beware of creating sparks (electrically or by use of toots). • Fuel vapour is heavier than air, so don't work on the fuel system with the vehicle over an inspection pit. • Another cause of fire is an electrical overload or short-circuit. Take care when repainng or modifying the vehicle wiring. • Keep a fire extinguisher handy, of a type suitable for use on fuel and electrical fires.
Electric shock x ^ ^ ? , • Ignition HT _ " voltage can be ^ dangerous, ~ especially to > people with heart problems or a pacemaker. Don't work on or near the f^ ignition system with fT") the engine running or ' J ' J the Ignition switched on.
• Mains voltage is also dangerous. Make sure that any mains-operated equipment is correctly earthed. Mains power points should be protected by a residual current device (RCD) circuit breaker.
Fume or gas intoxication • Exhaust fumes are poisonous: they often contain carbon monoxide, which is rapidly fatal if inhaled. Never run the engine in a confined space such as a garage with the doors shut, • Fuel vapour is also poisonous, as are the vapours from some cleaning solvents and paint thinners.
Poisonous or irritant substances • Avoid skin contact with battery acid and with any fuel, fluid or lubricant, especially antifreeze, brake hydraulic fluid and Diesel fuel. Don't syphon them by mouth. If such a substance is swallowed or gets into the eyes, seek medical advice. « Prolonged contact with used engine oil can cause skin cancer. Wear gloves or use a barrier cream If necessary. Change out of oll-soaked clothes and do not keep oily rags in your pocket. • Air conditioning refrigerant forms a poisonous gas if exposed to a naked flame {including a cigarette). It can also cause skin burns on contact.
Asbestos • Asbestos dust can cause cancer if inhaled or swallowed. Asbestos may be found In gaskets and in brake and clutch linings. When dealing with soch components It is safest to assume that they contain asbestos.
Special hazards
Hydrofluoric acid • This extremely corrosive acid is formed when cerlam types of synthetic rubber, found In some O-rings, oil seals, fuel hoses etc. are exposed to temperatures above 400;C. The rubber changes into a charred or sticky substance containing the acid. Once formed, the acid remains dangerous for years, tfit gets onto the skin, it may be necessary to amputate the limb concerned. • When dealing with a vehicle which has suffered a fire, or with components salvaged from such a vehicle, wear protective gloves and discard them after use.
The battery • Batteries contain sulphuric acid, which attacks clothing, eyes and skin. Take care when topping-up or carrying the battery. • The hydrogen gas given off by the battery is highly explosive. Never cause a spark or allow a naked light nearby. Be careful when connecting and disconnecting battery chargers or jump leads.
Air bags • Air bags can cause injury if they go off accidentally. Take care when removing the steenng wheel and/or facia. Special storage instructions may apply.
Diesel injection equipment • Diesel injection pumps supply fuel at very high pressure. Take care when working on the fuel injectors and fuel pipes.

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Warning: Never expose the hands, face or any otfterpart of the body to injector spray; the fuel can penetrate the skin with potentially fatal results.
Remember...
DO • Do use eye protection when using power tools, and when working under the vehicle. • Do wear gloves or use barrier cream to protect your hands when necessary. • Do get someone to check periodically that all is well when working alone on the vehicle. • Do keep loose clothing and long hair well out of the way of moving mechanical parts. • Do remove rings, wrtstwatch etc. before working on the vehicle - especially the electrical system, • Do ensure that any lifting or jacking equipment has a safe working load rating adequate for the job.
DON'T • Don't attempt to lift a heavy component which may be beyond your capability - get assistance. • Don't rush to finish a job. or take unverified short cuts. • Don't use ill-fitting toots which may slip and cause injury. • Don't leave tools or parts lying around where someone can trip over them. Mop up oil and fuel spills at once. • Don't allow children or pets to play In or near a vehicle being worked on.

Fuel system - diesel models 4C*3
Torque wrench settings Nm Ibfft Fuel injection pump roar bracket .. . 29 21 Fuel Injection pump .... 25 18 Fuel Injectors 41 Fuel pipe union nuts .... 30 22 Inlet manifold .... 24 18 Lower oil tiller mounting and injection pump mounting nut ..... .... 71 S2 Turbocnarger to exhaust manifold .... <10 30 Upper Dtl filter mounting end injection pump mounting nut 98 72
1 General information and precautions
General information The fuel system consists of a rear-mounted fust tank, a fuel filter with integral water separator, a fuel injection pump, in|eciors and associated components. A turbocharger is fitted to TDS, TD and TDSX models. Fuel Is drawn from the fuel tank to the fuel Injection pump by a vane-type transfer pump Incorporated in the fuel injection pump. Before reaching tho pump, the fuel passes through a fuel filter, where foreign matter and water aro removed. Excess fuel lubricates the moving components of the pump, and Is then returned to the tank. On turbo models with the Bosch fuel Injection systom, an eiectncally operated heater is incorporated In the fuel filter housing. The fuel injection pump is driven at half-crankshaft speed by the timing belt. The nigh pressure required to inject tho fuel into the compressed air in the swirl chambers Is achlovod by a cam plate acting on a single piston on the Bosch pumo, or by two opposed pistons forced together by rollers running in a cam ring on the Lucas (CAV) pump. Tlie fuel passes through acentral rotor with a single outlet drilling which aligns With ports leading to the Injector pipes. Fuel metering is controlled by a centrifugal governor, which reacts to accelerator pedal
position end engine speed. The governor is linked lo a metering valve, which increases or decreases the amount of fuel delivered at each pumping stroke. On turbocharged models, a separate device also Increases luel delivery with increasing boost pressure. Basic injection timing is determined when the pump is fitted. When the engine is running, it Is varied automatically to suit the prevailing engine speed by a mechanism which turns the cam plate or ring, Tho four fuel injectors proouco a homogeneous spray of fuel Into the swirl chambers located In the cylinder head. The Injectors are calibrated to open end close at critical pressures lo provide efficient and even combustion. Each injector needle is lubricated by fuel, which accumulates In the spring chamber and is channelled to the injection pump return hose by loak-off pipes Bosch or Lucas fuel system components mBy be fitted, depending on the model. Components from the latter manufacturer are marked either CAV. Roto-dlesel or Con-diesel. depending on their date and place of manufacture. With the exception of the fuel filter assembly, replacement components must be of tho same make as those originally fitted. Cold starting is assisted by preheater or glow plugs fitted to each swirl chamber. On the Bosch injection pump, an automatic cold Injection advance device operated through a thermal switch, advances the injection timing by Increasing the fuel pressure. The device operates at coolant temperatures below 55° C,
A stop solenoid cuts the fuel supply to V* Injection pump rotor when the ignition i switched off (see illustration) Provided that the specified maintenance* earned out. the fuel injection equipment #» give long and trouble-free service, ft* j injection pump itself may well outlast tlx ' engine, The main potential cause of damage j to the injection pump and injectors is dirt e water in the fuel. 1 Servicing of the injection pump and injectwi: j, is very limited for tho home mechanic, antf dismantling or adjustment other than thtf described In this Chapter must be entrusted to ' a Rat dealer or fuel Injection specialist.
Precautions

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Warning: It Is necessary to takt I certain precautions when woriong , on the fuel system component^ particularly the fuel Injectors. Befon carrying out any operations on tho fuel system, refer to the precautions given* Safety first! at the beginning of Mis manual, and to any additional wamlrq notes at the start of the relevant
Sections.

2 Air cleaner and inlet system ^ • removal and refitting S
Removal 1 Remove the air cleaner element u described In Chapter 1B (see illustration).
1.9 Stop solenoid on the injection pump 2.1 Releasing the air cleaner cover clips

5A«2 Starting and charging systems
5.9a Unbolting the alternator upper bracket from the rear of the coolant pump
fl Loosen the pivot bolt and adjustment locknut then unscrew the adjustment bolt and swivel the alternator towards the engine so that the drivebefi may be slipped off the alternator pulley. 9 Unscrew and remove the pivot and adjustment bolts and withdraw the alternator Irom the engine compartment. If preferred the upper alternator bracket may bo unbolted from the rear of the coolant pump {see illustrations).
Refitting 10 Refitting is a reversal ot removal. Refer to Chapter tA or 1B as applicable for details of tensioning the auxiliary drivebeit. On completion lighten the pivot and adjustment botts/nut to the specified torque.
6 Alternator -brush holder/regulator module renewal
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1 Remove the alternator as described in Section 5. 2 Extract the two small bolts and withdraw the brush box. Note the small plastic grille on the Marelli alternator (see illustrations), 3 Using a steol rule chock the length of the brushes. If less than 5.0 mm the complete brush holder assembly should be renewed. Note: On Bosch alternators it may be possible to obtain the brushes separate//, in which case the brush ieads should be unsoldered
5.9b Removing the pivot bolt and alternator from the engine
from ihe terminals and the new brush leads soldered onto the terminals. 4 Check the slip rings for excessive wear and clean them with a rag soaked in fuel. 5 Pit the new holder using a reversal of the removal procedure but make sure that each brush moves freely.
7 Starting system • & testing
Note: Refer to Ihe precautions given In Safety firstI and in Section I of this Chapter before stoning work. 1 If the starter motor falls to operate when the Ignition key Is turned to the appropriate position, the following possible causes may be to blame. aj The battery is faulty. b) The electrical connections between the switch, solenoid, battery and starter motor are somewhere failing to pass the necessary current from the battery through the starter to earth. c) 77:© solenoid is faulty. d) The starter motor is mechanically or electrically defective. 2 To check the battery, switch on the headlights. If they dim after a few seconds, this indicates that the battery is discharged -recharge (see Section 2) or renew the battery. If the headlights glow brightly, operate the ignition switch and observe the lights. If they
dim, then this indicates that current it reaching the starter motor, therefore the iao8 must lie In the starter motor. If the lights continue to glow brightly (and no clicking sound can be heard from the starter motor solenoid), this indicates that there is a lairt
In
the circuit or solenoid - see following paragraphs, if the starter motor turns siowfy when operated, but the battery is In good condition, then this indicates that either lae starter motor is faulty, or there is considers resistance somewhere in the circuit. 3 If a fault in the circuit is suspected, disconnect the battery ieads (including ihe earth connection to the body), lt» starter/solenoid wiring and tne engine/transmission earth strap. ThoroygWy clean the connections, and reconnect the leads and wiring, ihen use a voltmeter or J«i lamp to check that full battery voltage is available at the battery positive lead connection to the solenoid, and that the earth is sound. Smear petroleum jelly around ttie battory terminals to prevent corrosion > corroded connections are amongst the most frequent causes of electrical system faults. 4 If the battery and all connections are in good condition, check the circuit disconnecting the wire from the solenod blade terminal. Connect a voltmeter or less lamp between the wire end and a good earth (such as the battery negative terminal), ais check that the wire is live when tne ignition switch is turned to the start position. If It is. then the circuit is sound - if not. the circut wiring can be checked as described Chapter 12. Section 2. 5 The solenoid contacts can be checked
Oy
connecting a voltmeter or test lamp across Ihe solenoid. When the ignition switch is turned to the start position, there should b»a reading or lighted bulb, as applicable. II thars is no reading or lighted bulb, the solenoid is faulty and should be renewed. 6 If the circuit and solenoid are proves sound, the fault must lie in the starter motor. In this event, it may be possible to have tre starter motor overhauled by a specialist, but check on the cost of spares before proceeding, as It may prove more economical to obtain a new or exchange motor