fuel switch FIAT PUNTO 1995 176 / 1.G Owner's Manual

5A«2 Starting and charging systems
1 General information and precautions
General information The engine electrical system consists mainly of the charging and starting systems. Because of their engine-related functions, these components are covered separately from the body electrical devices such as the Ilght3, Instalments, etc (which are covered In Chapter 12). On petrol engine models refer to Part B for information on the ignition system, and on diesel models refer to Part C for information on the preheating system. The electncal system Is of 12-volt negative earth type. The battery fitted as original equipment is of maintenance* free (sealed for life} type and Is charged by the alternator, which is belt-driven from the crankshaft pulley. If a non-original battery is fitted It may be of standard or low maintenance type. The starter motor is of the pre-engaged type Incorporating an integral solenoid. On starting, the solenoid moves the drive pinion into engagement with the flywheel ring gear before the starter motor is energised. Once the engine has started, a one-way clutch prevents the motor armature being driven by the engine until the pinion disengages from the flywheel.
Precautions Further details of the various systems are given In the relevant Sections of this Chapter. While some repair procedures are given, the usual course of action is to renew the component concerned. The owner whose interest extends beyond mere component renewal should obtain a copy of the Automobile Electrical & Electronic Systems Manual, available from the publishers of this manual It Is necessary to take extra care when working on the electrical system to avoid damage to semiconductor devices (diodes and transistors), and to avoid the risk of personal injury. In addition to the precautions given in Safety first! at the beginning of this manual, observe the following when working on the system: Always remove rings, watches, etc before working on the electrical system. Even with the battery disconnected, capacitlve discharge could occur If a component's live terminal is earthed through a metal object. This could cause a shock or nasty bum. Do not reverse the battery connections. Components such as the alternator, electronic control units, or any other components having semi-conductor circuitry could be irreparably damaged. If the engine is being started using jump leads and a slave battery, connect the batteries positive-to-posibve and negative-to-
negative (see Jump starting). This also applies when connecting a battery charger but In this case both of the battery terminals should first be disconnected. Never disconnect the battery terminals, the alternator, any electrical wiring or any test Instalments when the engine Is running. Do not allow the engine to turn the alter-nator when the alternator Is not connected. Never test for alternator output by flashing the output lead to earth. Never use an ohmmeter ot the type Incorporating a hand-cranked generator for circuit or continuity testing. Always ensure that the battery negative lead is disconnected when working on the electrical system. Before using electric-arc welding equipment on the car, disconnect the battery, alternator and components such as the fuel Injection/ignition electronic control unit to protect them from the risk of damage. Several systems fitted to the vehicle require battery power to be available at all times, either to ensure their continued operation (such as the clock) or to maintain control unit memories or security codos which would be wiped if the battery were to be disconnected. To ensure that there are no unforeseen consequences of this action. Refer to Disconnecting the battery In the Reference Section of this manual for further Information.
2 Battery- % testing and charging
Standard and tow maintenance battery - testing 1 If the vehicle covers a small annual mileage, it is worthwhile checking the specific gravity of the electrolyte every three months to determine the state of charge of the battery. Use a hydrometer to make the check and compare the results with the following table, Note that the specific gravity readings assume an electrolyte temperature of 15*C (60'F); for every 10*C (18°f) below 158C (60aF) subtract 0.007, For every 108C (16'F) above 15"C (60'F) add 0.007. Ambient temperature Above 26"C Below 25DC Charged 1,210 to 1£30 1,270 to 1.290 70% charged 1.170to1.l90 1.230to1.250 Discharged 1.050toJ.070 1.110 to 1.130 2 If the battery condition is suspect, first check the specific gravity of electrolyte In each cell. A variation of 0.040 or more between any cells indicates loss of electrolyte or deterioration of the internal plates. 3 If the specific gravity variation is 0.040 or more, the battery should be renewed. If the cell variation Is satisfactory but the battery is discharged, it should be charged as described later in this Section.
Maintenance-free battery -testing 4 In cases where a sealed tor life maintenance-free battery is fitted, topplng-up and testing of the electrolyte in each cell Is not possible. The condition of the battery can therefore only be tested using a battery condition Indicator or a voltmeter. 5 Certain models may be fitted with a maintenance-free battery with a built-in charge condition Indicator. The indicator Is located in the top of the battery casing, and indicates the condition of the battery from its colour. If the Indicator shows green, then the battery is In a good state of charge. If the Indicator turns darker, eventually to black, then the battery requires charging, as described later in this Section. If Ihe indicator shows clear/yellow, then the electrolyte level in Ihe battery is too low to allow further use, and tho battery should be renewed. Do not attempt to charge, load or Jump start a battery when the indicator shows dear/yellow. 6 If testing the battery using a voltmeter, connect the voltmeter across the battery and compare the result with those given In the Specifications under 'charge condition'. The test is only accurate if the battery has not been subjected to any kind of charge for the previous six hours. If this is not the esse, switch on the headlights for 30 seconds, then wait four to five minutes baforo testing the battery after switching off the headlights. All other electrical circuits must be switched off, so check that the doors and tailgate are fully shut when making the test, 7 It the voltage reading Is less than 12.2 voHs, then the battery Is discharged, whilst a reading of 12.2 to 12.4 volts indicates 8 partially discharged condition. 6 If the battery Is to be charged, remove It from the vehicle (Section 3) and charge it as described later In this Section.
Standard and low maintenance battery - charging Note: The following is Intended as a guide only. Always refer to the manufacturer's recommendations (often printed on a label attached to the battery) before charging a battery. 9 Charge the battery at a rate of 3.5 to 4 amps and continue to charge the battery at this rate until no further rise In specific gravity Is noted over a four hour period. 10 Alternatively, a trickle charger charging at the rate of 1.5 amps can safely be used overnight. 11 Specially rapid boost charges which are claimed to restore the power of the battery in t to 2 hours are not recommended, as they can cause serious damage to the battery plates through overheating, 12 While charging the battery, note that the temperature of the electrolyte should never exceed 37.8*C(100°F),

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
%
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

5B*2 Ignition system - petrol models
1 HT leads 2 Support 3 Cover mounting bdt 4 Ignition coifs
5 Washer 6 Washer 7 Coil mounting bolt
1.2s Ignition coils and HT leads 9 Washer 10 Coil mounting bracket
11
Nut
12 Waslrer 13 Spark plugs 14 Coll cover 15 HT lead support
16 HT lead support 17HTlead support 18 Seat Id Bracket
1 General information
The ignition system is integrated with the fuel injection system to form a combined engine management system under the control of one ECU (see the relevant part of Chapter 4 lor further Information). The Ignition side of the system is of the static (distributorless) type, consisting only of two twin-output Ignition coils located on the left-hand side of the cylinder head. Each ignition coil supplies two cylinders (one coll supplies cylinders 1 and 4, and the other cylinders 2 and 3) (see Illustrations). Under the control of the ECU, the ignition coils operate on the wasted spark principle, ie. each spark plug sparks twice for every cycle of the engine, once on the compression stroke and once on tho exhaust stroke. The spark voltage is greatest in the cylinder which Is under compression, the other cylinder
having a very weak spark which has no effect on the exhaust gases. The ECU uses Its Inputs from the various sensors to calculate the required ignition advance setting and coil chorging time.
1.2b Ignition coll circuit 1 Primary windings 2 Secondary windings 3 Power module
ECU) 4 Spark plugs
2 Ignition system -testing i

A


Warning: Voltages produced
by
an electronic Ignition system an considerably higher than (hose produced by conventional Ignition systems. Extreme care must be tak»n when working on tho system with thi Ignition switched on. Persons wilfl surgically-implanted cardiac pacemaker devices should keep well clear ot the ignition circuits, components and (oaf equipment 1 If a fault appears In the engine management (fuel injection/ignition) system first ensure that the fault is not due to a poor electrical connection or poor maintenance: ie, checK lhat the air cleaner filter element is clean, tht spark plugs are In good condition and correctly gapped, lhat the engine breather hoses are clear and undamaged, referring to