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Lucss F a u f tD i a g n o s i s S e r v i c eM a n u a l m- &, ia._ trwtrFi] U i,rull w7 / \ oott @ F., t__j C a t a l oN g o .X l A l 1 6 F a u l tD i a g n o s i s S e r v i c eM a n u a l Informationcontainedhereinhasbeencarefully researched reliablesources.Whileall information is believed to be completeand accurate, we cannotacceptresponsibility for anyerroror omission.We reserve the right t o m a k ea n y n e c e s s a rcyh a n g e sa t a n yt i m e ,w i t h o u tn o t i c e .S h o u l da n e r r o ro r o m i s s i o n b e f o u n d ,p l e a s e reportit immediatelyto the LucasAftermarket OperationsMarketingDepartment. lntroduction F a u l td i a g n o s i s itsh em e t h o do i l o c a t i n gf a u l t sw h i l et h ee l e c t r i c aelq u i p m e ni st s t i l li n s i r u . ln rlre interestsof efficiency and.economy, the?iagnosismust be accuratednd mustbe carriedort in ii.,. s h o r t e spt o s s i b l et i m e u s i n gt,h e m i n i m u m - a m o u nor f e q u i p m e n t .l t i s t h e a i r n o r i t i i i " " r ' i " presenta logica.lseqqgnc_e3f tgststhat may be carriedout bn' the varioussections or tneequilmen t in order to achievethis objective The.majorito y f p r o c e d u r ei n s v o l v ec i r c u i tr e s t i n ga n d t h e p r i n c i p l eu s e dw i l l b e t h a t o t ' c l r e c k i n g l o r " v o l t a g ed r o p " w h e r ea v o l t m e t e irs c o n n e c l e di n p a i a l l e lw i t h t h e p a r t i c u l a r . i r c r l t io-U! tested. As.voltagedrop existsonly whencurrentis flowingand variesaccordingto the amount.of current i t i s e s s e n t i at h l a t t h e c i r c u i ti s c h e c k e d" u n d e r - l o a d " ,1 . . . * f i i l i i p a - s s i n !i t r ' r " i * r i ' . r . r . " , . ln certaininstancesthis currentwill be measuredusinga testammeiei. T h e a c c e p t a b lveo l t d r o p f i g u r ef o r m o s tc i r c u i t si s l O / , o f s y s t e mv o l t a g e( 1 . 2v o l t so n a l2 voir system)but thereareexcep-tions to thisrule as in the caii of the starterciiuit wherethe maximum voltagedrop allowedis 0.5 volts. Throughoutthe procedures whereveran exceptionappliesthis figurewill be clearlystated. T h e f o l l o w i n gi s t h e m i n i m u me q u i p m e nnt e c e s s a rt yo c a r r yo u t t h i s f a u l td i a g n o s i s : l. D.C. voltmeter(movingcoil; 4" openscale0_40volts. 2. -D.C.am,meter (movingcoil) 4" openscaletO_0_100 amp.' Note: The voltmeterand ammetercan be obtainedin a test box form as sho*,n. l . H y d r o m e t e(rF i g . l ) . 4. Heavyduty batterydischargetester(Fig. 2). 5. Ohmmeter. Page2 Fig. 1 T y p i c a lt e s ! b o x a n d h y d r o m e t e r Fig. 2 H e a v y d g s y b a c c e r yd i s c h a r g et e s r e r Contents Page(s) 2 INTRODUCTION .,. BATTERIES )-v STARTERS l0- t4 IU Battery check Checkingthe startersystem(inertiadrives) drives) Checkingthe startersystem(pre-engaged l0-ll l2-t4 l5-25 COIL IGNITION 16-r9 t9-21 Standardcoil ignitionsystem Ballastedignition sYstem Opus ignitiontestProcedure Staticignitiontiming timing Stroboscopic 1a 25 25 26-30 DYNAMOS AND CONTROL BOXES 26 26-21 27 7'7-28 29 29-30 Battery test Checkingdynamo Checking dynamo leads Compensatedvoltage cont Ignition warning light Current voltage control J I _ J / ALTERNATORS Batterytest i0/ll AC systems l 5 l l 6 l l 7 l l 8 l 2 0 A C Rs y s t e m s Battery test 32 32-35 36-37 ... JO 3 8- 4 l LIGHTING Sideand tail light circuit ... . Voltageat the batteryunde, ' t " " 0 . . . . . . Headlights,stop iightsancidirectioninciicatorcircuits... Headlampalignment WIPER MOTORS Wiper testprocedure 1A )t ... .. 39 39 4l 42-44 42 Page3 BATTERIES INTRODUCTION B A T T E R I E Sl N s E R V l c E ( F i g . 3 ) The lead-acidbatteryis a deviceusedto convertand store electrjcalenergyin a chemicalform and as the n a m e i m p l i e st h e b a s i ca c t i v em a t e r i a l sa r e l e a d a n d sulohuricacid. fhe purpos"of the batteryon thevehicleis primarily to provide current for the operation of the starter b u t i t a l s os u p p l i e so t h e re q u i p m e ntth a t m a y b e u s e d w h i l s t t h e v e h i c l ei s s t a t i o n a r y e. . g . r a d i o , p a r k i n g lightse , tc. During the courseof normal running,the batteryis recharged by the vehiclechargingsystemand provided the vehicledoesenoughrunningtime, will havestored energyreadyfor the next start operation. N o t e : A v e h i c l es t a n d i n gi d l e w i l l z D r m a i n t a i n a chargedbattery. As a battery fault can have adverseeffectson the operation of the various systems,particularly the starting and charging system,some knowledgeol b a t t e r yt e s t i n gi s a n e s s e n t i apla r t o f f a u l t d i a g n o s i s . l . C L E A N A N D D R Y - t h e b a t t e r yp, a r t i c u l a r l tyh e t o p m u s tb e k e p tc l e a na n dd r y . W a t e rs p i l l a g e ! c . during topping-up must be immediatelywiped away. 2 . E L E C T R O L Y T E L E V E L- t h e e l e c t r o l y t em u s t b e m a i n t a i n e da t r h e c o r r e c t h e i s h t w h i c h i s n o r m a l l yl e v e lw i t h t h e t o p s o f t h e - s e p a r a t o o r sr t h es p l a s h g u a r d . l . T O P P I N C - U P - s h o u l db e c a r r i e do u t w h e n t h e electrolytefalls below the correct level. Only distilledwater or de-ionised water must be added to replaceelectrolyte lost by evaporation. 4 . S T A T E O F C H A R G E - t h e b a t t e r ym u s tn e v e rb e lelt in a disdharged state. A batteryin a poor state of chargei.e.lessthanT0l shouldbe rem6vedand chargedfrom an independent sourceat the normal rechargerate. Otherwisethe platesmay become ( h a r d e n e dm) a k i n gi t d i f f i c u l tt o a c c e p r sulphated CLEANAND DRY _'-- CORRECT ELECTROLYTE LEVEI \' SM WITH PETR( JELLY & DRY Fig.3 B a t t e n e si n s e r v r c e Page5 a charge,with the consequent early failure of the battery. Ensurethat the generatordrive belt is adjusted correctlyand that it does not rest on the bottom of thepulleys. 5. 'clamped INSTALLATION - the battery mu'st be securely (not overtight)to preventdamagefrom vibration, which may causesheddingof active material from the plates resultingin a loss of capacityor short-circuitbetweenthe plates, The stowagearea.mustalso be kept cleanand dry. Any acid spillageshould be removedwith household ammonia or baking soda and hot water. otherwisethe metalwill be extensively damagedby corrosion. The metalwork should be repainted w i t h a c i d - r e s i s t i npga i n t a f t e r t h e c o r r o s i o nh a s beenneutralised. C A R E o F B A T T E R Y L U G S ( F i g .a ) The effectof acid corrosionis far more seriousthan is generallyrealised.For example,excessive corrosion of the batterylugswill leadto sluggishoperationof rhe starter. This is due to voltagedrop at the battery terminals,when the high startercurrentis flowing. The lead die-cast lug is designedto reduce rhe possibilityof corrosion to a minimum and is fitted almostexclusively to Britishcarstoday. T h e S . M . M . T . l u g , c l a m p t y p e ,i s u s e dm a i n l y o n commercialand passenger vehicles. ln both casesthe lug shouldbe clearedof oxidation and the lug and battery post smearedwith petroleum jelly as an addedprecautionagainstcorrosion. When fitting the die-castlug, ensurethat it is in full contact with the terminal post by pressingit down firmly and securingit in positionwith the self-tapping screw. Do n o t l s e t h es c r e wt o p u l l t h el u gd o w no n t o t h €t e r m i n a l post. Neveruselbrce when removinglugs. If. as a result of corrosion.a lug cannot be removedeasily,soak a t-,tE t-45 r (HELMET) TYPE Fig. 4 Typesof batcerylugs Page6 cloth in hot water and apply it to the corrodedlug. After freeingthe lug, removeall tracesof corrosion. C O R R E C TC H A R G I N G The importanceof correctchargingcannotbe overemphasised as far as the life of the battery is concerned. The batteryshouldnot be allowedto standin a low in the winterwhenthe electrostateof chargeespecially lyte could freezedue to its low specificgravity. li. however,the batteryshouldbecomefully discharged, ir shouldnot be left on the vehiclein the hopethat ir will become fully rechargedby the vehicle'scharging system. Unlessthe battery is chargedby an external sourceit will probablyneverbecomemore than halfcharged,and even though it appearsto be working satisfactorily, the plateswill hardenand the life of the batterywill be considerably shortened. presents Generallyspeaking, recharging no problems il the rechargingratesquotedon the instructionlabels are adheredto. The normal chargerate is approximately one-tenthof the A/H capacityof the battery at the l0 hour rate or 20 hour rate. CHARGING METHODS Either the constant current method, which we advocatedfor initial charging,or the constantvoltage methodmay be employedlor recharging.ln eithercase a DIRECT CURRENT supply must be used. The connections to be madedifferwith the methodand can be seenfrom'thediagram. You will seethat, usingthe constantcurrent method(Fig. 5), .thebatteriesare in series.Thus, a limit is set to the numberof batteries that may.bechargedin series,sincethe voltageof the whenfully chargedmustnot exceedthesupply batteries voltage. lt is found in practicethat the most suitable arrangementis ten 6 volt batteriesor five 12 volt batterieswhenchargingfrom a ll0 volt supply. With the constant voltage system (Fig. 6), the batteriesare connectedin parallel.usuallyto a low SMMT (CLAMP) TYPE CONSTANT CURRENTCHARGING F inann-€ AMMETEFI l ! 44I I U flf- Fig.5 \ /-r r V U L I <r roc)r v C o n s t a n tc u r r e n t c h a r g i n g CONSTANT VOUTAGE D.C. SUPPLY CONSTANT VOLTAGE CHARGING Fig. 5 Constant voltage charging voltagemotor-generator s€t. The numberof batterres that can be chargedby one generatoris limited by the rated current output of the generator, and the total chargingcurrent requiredfor all the batteriesmust not exceedthis output. The supply voltage can again be regulatedby a rheostat,and, if necessary, a rheostator resistance can be includedin the supply line to an individual battery wherea lower chargingrate is required. TEST l. Battery Testing- Hydrometer . Testingshould commenceat the sourceof supply; the battery itself. If the battery is dischargedor uDserviceable,the readings in the other tests will be affectcd. There is a relationshipbetweenrhe state of battery charge and the strength of the electrolyte. As thi battery becomesdischarged,the specificg-ravity(S.G.) of the electrolytebecomeslowei. ThtS.G.'df tni electrolyteis measuredby meansof a hydrometer. This instrumentconsistsof a glasstube, with a rubber bulb fitted -cn one end. Inside the tube, there is a float. which is calibratedfrom 1.130to 1.300. When the end of the hydrometeris insertedin the battery cell, as shown in Fig. 7, and the rubber bulb is pressedand then released,a small quantitv of the electrolyteis drawn into the tube. The'positi6n of thc float is determinedby the specificgraviry of the clectrolyte. When the specificgravity is high,-thefloat maintains.a high positio-ninsidethe tube,aud if the specific gravity is low the float sinks to a lower position. Pagc7 Twin cadmium test PageE From the specificgravity (S.G.) readings,a fairly accurateindication of the battery state of chargecan be obtained. SpecificGravity Readings State of Charge Fully charged 701 charged Discharged Climates Climates normallybelow normallyabove 25'C (77"F) 25"C (77"F) t.27|U-^t.290 L210-1.230 1.170-r.r90 l .230-I .250 1 . 1 1 0 - 1 . 1 3 0 1.050-1.070 Note: The hydrometerreadingsshouldnot be taken if the battery has only just been topped up. It shouldbe chargedfor I to 2 hoursbeforetaking . any reaolngs. TEST 2. Battery Testing- Heavy DischargeTest This test should be carried out as a further check of the battery condition. A heavydischargetestershould be applied to the battery terminalsas shown in Fig. 8. The i6st ensuresthat the batteryis capableof supplying theheavycurrentsrequiredby thestarterat the moment of starting the engine. The tester should be set to dischargethe battery at rhreetimes the amperehour capacity(20 hr rate) for l5 seconds.(Example: lf the battery has a capacity of 50 Ah (20 hr rate),the testershould be setto 150amps on the ammeter). Observethe voltmeterduring the batterydischarge.If the voltmeterreadingis 9.6V or above, the battery is consideredsatisfactory. If the voltage falls below 9.6V, the battery is suspectand should be removedfor further testing. TEST 3. Battery Testing- Twin CsdmiumTest Chargea l2 volt batteryat (mamps(or at the20 hour rate, whicheveris thc lower) for 3 minutes. At the end of three minutesand with the battery still on charge(Fig. 9), recordthe overall voltageand the 5 i n t e r c e rl le a d i n g(si . e .I a n d2 , 2 a n d 3 , 3 a n d 4 ,4 a n d 5 , 5 and 6) usingcadmiumsticks. Subtractthe lowest intercellvoltagereadingsfrom the highest. CONCLUSION ( a ) I i t h e v a r i a t i o ni s 0 ' 1 5 v o l t s o r m o r e ,t h e b a t t e r y needsreplacing. (b) If the variation is lessthan 0.15 volts and the is lessthan 15.5for a l2 volt battery batteryvoltage or 7.75for a 6 volt battery,the batteryis satisfactory but dischargedand only in need of a fast charge. (c) If the variation is less than 0'15 volts and the batteryvoltageis 15.5or over for a l2 volt battery (7.75for a 6 volt battery)the batteryis discharged (and may be sulphated). Page9 STARTERS INTRODUCTION The starter is a motor which convertselectrical energy,supplied flrom the battery, into mechanical energyfor the purposeof crankingthe engine. Thereare two basictypesof starter,the inertiatype and the pre-engaged type,employingdifferentmethods of couplingthe starterdrive pinion to the engineflywheelring gear. The inerria type - usedon the majority of cars and light commercials employingpetrolengines.Whenthe starter is energisedrapid increaseof speed at the armature and screwedsleeve,'carrying the pinion. causesthe pinion to move along the sleeve(due to its inertia)and engagethe ring gear,thusrotary movemenr is transmittedto the engine,the ratio betweenthe starterqinion and the ring gear,being approximately l0: I . Whentheenginefiresandthe flywheelaccelerates to drive the pinion faster than the rotation of the armature,the pinion is ejectedback along the screwed sleeveand consequently disengaged from the engine. The pre-engagedtype - used on heavier petrol enginesbut particularly suitableon diesel engines. where,due to intermittentfiring characteristics and crankingspeedsurges(highcompression) the pinionof the normalinertiatype would be ejectedprematurely. B y t h e o p e r a t i o no f a s o l e n o i dt h e s t a r t e rp i n i o ni s engagedwith the flywheelring gear beforethe starter is energised, after which the pinion can be retainedin mesh for as long as is necessary to start the engine. W h e nt h ee n g i n ei s f i r i n ga n dt h ep i n i o nb e i n gd r i v e na t high speedby the flywheel,the armatureis protected againstoverspeedingby the freewheelaction ol a r o l l e ro r p l a t ec l u t c h . F i g . 1 0 E a c r e r yr e r m i n a l v o l t a g eu n d e r l o a d Page.l0 F i g . 1 1 S t a r c etre r m i n a vl o l c a g u e n d e rl o a d TEST I. Battery Test U s i n g a h y d r o m e t e rc, h e c k r h a t t h e b a t t e r y i s a r least701charged. The full battery-test procedureis o u t l i n e di n S e c t i o nl . N o t e : A b a t t e r yi n p o o r c o n d i t i o nw i l l c a u s ed i f f i c u l t starting. C H E C K I N G T H E S T A R T E RS Y S T E M ( T N E R T T AD R T V E S ) lf the previoustest has proved that the batrery is satisfactory,a moving coil voltmeter(0-40V range) shouldbe usedto determinewhetherthereis excessive v o l t a g ed r o p i n t h e c i r c u i t . N o t e ; D u r i n gt h e v o l t m e t ecr h e c k st,h e s t a r t e rs h o u l d c r a n kt h e e n g i n ew , i t h o u ts t a r t i n gi t . Petrol engines.' The low-tensioncircuit of the i g n i t i o nc o i l s h o u l db e d i s c o n n e c t e bd etween the c o i la n d d i s t r i b u t o r . Diesel engines.Operate engine stop so that e n g i n ew i l l n o t s t a r t . TEST 2. Checkingthe BatteryTerminalVoltage underLoad Conditions This checkenablesthe workingvoltageat the battery to be verified. Fig. l0 shows a voltmeterconnectedbetweenthe positiveand negativebatteryterminals. The reading is noted when the starrer switch is operated.The readingsfor a 12volt systemdependson the enginecapacity,battery size (Ah) and type of starter. A typical figure for petrol enginesis about 10.0volts. Proceedto Test 3. A low voltage reading would indicate excessive c u r r e n ti n t h e c i r c u i t . T h e s t a r t e rs h o u l db e r e m o v e d for benchtesting. Checkingthe Starter TerminalVoltage under Load Conditions the batteryvoltage'the voltage Havins ascertained slarteris checked'Fig' I I showsa voltmeter ".iott'tft? between the starter terminal and earth """"Li.a iJ"rn*"t"t"i end bracket).Whenthe starteroperating betweenthis readingand l*ircft ii .i"ted, the difference ift"il.t"n at the batteryshouldnot exceed0'5V' proceedwith the If the voltage drop is excessive following tests. TEST 3. Checkingthe VoltageDrop on the InsulatedLine as For this test the voltmetershould be connected between rno*n in fig. 12. The voltmeteris connected t?t-inat and the batterv supplvterminal' ;il; ;il;; When the operatingswitchis open, the voltmeter bu.twhenthe operating ,trot iJ'i.gitter'battery-volrage, ;;;t"h ;-;i"ted the voltmeteireadingshouldbe noted' TEST 4. TEST 5. Checkingthe VoltageDrop acrossthe SolenoidContacts The solenoid contactscan be checkedfor voltage droo bv connectinga voltmeteracrossthe two main ino*i in Fig. 13. when the operating i.#i#rr-"t open, the voltm;ter should registerbattery ;;;i;hii operatingswitchis closed'the volt""ii^t..-when'the be noted' should meter-reading 'Cbeckingthe VoltageDrop on the TEST 6. Earth Line To checkthe voltagedrop on the earthline' connect tne vo-ltmeterbetwee-nthe battery earth te.rminaland iii" tt.tt.. earth (commutatorend bracket),as shown in pin. 14. When starteroPeratingswitch is closedthe readingshouldbe practicallyzero' volta"ge Fig.14 V o l t a g ed r o p o n t h e e a r t h l i n e F i g . 1 5 C h e c k i n gt h e e a r t hc o n n e c t i o n s TEST 7. CheckingEarth Connections Connect the voltmeter betweenthe chassis.of the ueh-icie'andthe battery earth termin"t (lje' l5)' Operatethe starter. Once again note tne reaolng' Fig.17 TEST 8. CheckingBondingStrap (fig' 10 As most vehicle enginesare rubber mounted, the UoJin!-tt."p must mike a qood electricalconnection betweenthe englneorock aid the chassis'The units block (i'e. distributor,dynamo ."""i.a on the-engine must hive an efficientearth connectionin ;;e;i;;t order to function correctlY. If the bonding straPis incorrectlyfitted or frayed'.it u t"tiout effect on the performanceof the *iii il; starter,and may evenimmobilisethe vehicle' Note: ?'he total voltagedrop on the starler installation mustnot exceed0'5Y. V o l t a g ed r o p o n t h e i n s u l a t e dl i n e FEED Fig. 13 V o l t a g e d r o p a c r o s st h e ' o l e n o i d c o n l a c t s Fig. 16 C h e c k i n gt h e b o n d i n g s t r a P Pagc1l v o l t a g eu n d e r CHECKTNG THE STARTERSYSTEM (PREENGAGED DRTVES) The procedure for checking for excessivevoltage drop in the pre-engagedstartercircuit is similar to that used for inertia drive starter systemsbut in addition, the,voltageavailablcat the solenoidfeedterminal must be checked. The completeprocedureis as follows: TEST l. Checkingthe BatteryTerminatVoltage under Load Conditions Connectthe voltmeteracrossthe terminals.as shown in Fig. l7 and operatethe starterswitch. The readings for a 12 volt system depend on the engine capacity, battery size (Ah) and type of starter. A typical figure for petrol enginesis about l0-0V, and for dieselengine (l2V system),9'0V. A low voltage reading would indicate excessive current flow in the circuit. The startershould then be removedlor bench testing. Note: If the solenoidoperates intermittentlyduringthe test or the engineis crankedat a low or irregular speed,there may be insufficientvoltage at the solenoid operating winding terminal or the solenoidis faulty. To check the switchingcircuit for high resistance, connect the voltmeter between the solenoid operating winding terminal and earth (commutatorend bracket)as shownin Fig. 18. When the switchcontactsare closed,the readingon the voltmetershould be slightlylessthan the readingin Test l. A satisfactory reading indicatesa negligible voltagedrop in the circuit and consequentlythe fault may be in the solenoid. If the reading is appreciablylower than in Test l, checkthe switchingcircuit for high resistance or faulty connections.Check the cablesizeis as recommended, i.e. 28/0.30mm (28/.012"). In order to reduce voltage drop in tbe switching circuit on some vehicle applicationsa 4ST solenoidis incorporatedin the circuitas shownin Fig. 18a. Page 12 Fig. 18 C h e c k i n gt h e s o l e n o i ds w i t c h i n gc i r c u i t TO BATTERY F i g .l 8 A S o l e n o i sdw i t c h i n gc i r c u i ti n c o r p o r a c i n g a d d i t i o n aslo l e n o i d( 4 S T ) TEST 2. Checkingthe Starter Terminal Voltage under Load Conditions the battery voltaglunder load, Having ascertained the voltageacrossthe starteris checked.Fig. l9 shows a voltmEter connected between the starter inPut terminaland earth (commutatorend bracket). When the operatingswitch is closed,the differencebetween this readinglnd that taken at the batteryshouldnot exceed0'5V. If the readingis within this limit, the startercircuitis satisfactory.Il thereis a low readingacrossthe starter, it indicates but the voitageat the batteryis satisfactory, a h i e h r e s i s t a n ci en t h e s t a r t e rc i r c u i t . Fig. 19 S t a r t e r r e r m i n a l v o l t a g eu n d e r l o a d Fig. 20 V o l t a g ed r o p o n t h e i n s u l a t e dl i n e TEST 3. Checkingthe VoltageDrop on the lnsulatedLine The voltage drop on the insulated line is then checked. Fig. 20 shows the voltmeter connected betweenthe starter input terminal and the battery (insulated) termina[. When the operatingswitch is open, the voltmetcr should registerbatteryvoltage. When the operating switch is closed, the voltmeter reading should be practicallyzero. A high voltagereadingindicatesa in the insulatedline. high resistance All insulatedconnectionsat the battery, solenoid and startershouldbe checked. P a g eI 3 lf all connectionsare in order, the startersolenoid contactsmust be checked.(Proceedto Test 4). TEST 4. Checkingthe VoltageDrop acrossthe SolenoidContacts To checkthe voltagedrop acrossthe solenoidcontacts, connect the voltmeter across the two main s o l e n o i dt e r m i n a l s a, s s h o w n i n F i g . 2 1 . W h e n f h e operatingswitchis open,the voltmetershouldregister batteryvoltage. When the operatingswitch is closed, the voltmeterreadingshouldfall to a fractionalvalue. 'zero A or fractional reading on the voltmeter indicatesthat the high resistancededucedin Test 3 must be due eitherto high resistance startercablesor solderedconnections. A h i g h r e a d i n g( s i m i l a rt o t h a t i n T e s t l ) i n d i c a t e s l a u l t ys o l e n o i dc o n t a c t s . TEST 5. Checkingthe VoltageDrop on the Earth Line F i n a l l y , ' c h e c kt h e v o l c a g ed r o p o n t h e e a r t h l i n e . Connectthe voltmeterbetweenthe batteryearth terminal and the starterearth (commutatore;d bracket) a s s h o w ni n F i g . 2 2 . N o t e r e a d i n g s . Fig.22 Page14 Vokage drop on rhe earth line Fig.2l V o l t a g ed r o p a c r o s tsh e s o l e n o i d conracrs N o t e : l . C h e c ke a r t h c o n n e c t i o nasn d b o n d i n gs t r a p as describedin the "lnertia Starter" iection (Tests7 and 8). 2 . T h e t o t a l v o l t a g ed r o p i n t h e s t a r t i n gc i r c u i t ( i . e .i n s u l a t e dl i n e a n d e a r t hl i n e ) m u s r n o r exceed0.5V. colL IGNITION INTRODUCTION The function of the ignition systemis to provide suffi.cient voltageat the spark plugsto ignite the petrol/ air mixture in the cylinders,as eachpistonapproaches the correct firing position,i.e. a few degreesbefore too dead centre on compressionstroke. The exact ntimber of degreesvarieswith differentenginesand will be specifiedby the enginemanufacturers. The amount of voltageneededwill also vary with a number of factors such as enginetemperature,compressionratio, sparkplug gap. Although the standardignition systemwill quite adequatelymeet the requirementsof a six-cylinder engineup to approx.8,000rev/min, any increasein speedrequirements or in the numberof cylinderswill placeextra demandon the system Ignition systemscan be produced to compiy with these additional demands. For example,ballasted systemsto facilitate easiercold starting or electronic systemsto provide high sfieedoperation on multicylinderengines. The systems dealtwith in this sectionare: (a) Standardcoil ignition. (b) Ballastedignition (easystart). (c) OPUS(Oscillating pick-upsystem- fully electronic, no contacts). Fig. 23 showsa typicalcoil ignition circuit. F i g . 2 3 T y p i c acl o i l i g n i t i o nc i r c u i t P a g ei 5 Ammeter LightingSwitchOn lgnitionSwitchOn TEST 4. Voltageat '-' Terminal of Coil (ContactsOpen) Next, the primary winding is checked for continuity. The contactpoints must be open. A voltmeter '-' terminal of the coil and is connectedbetweenthe earth (Fig. 27). When the ignition is switched-on, the voltmeter should register battery voltage. If a zero readingis obtained,it indicates: l. The primary winding of the ignition coil may be open-circuit,or 2. Tbere may be a short-circuit to earth in the distributor or in the coil-distributorlead. To help ascertainthe actualcauseoffailure, the lead from the'-"L.T.'terminal of the coil is disconnected, and anothervoltmeter readingis taken. (a) If a zero reading is obtained,there is a break in the primary winding. (b) If the voltmeter registers battery voltage, the short-circuitis eitheron the coil to distributorlead or within the distributor. Warning l-ight Fig. 24 Battery- rapid check STANDARD COIL IGNITION SYSTEM TEST 1. Bettery: Rapirt Check (Fig. 2a) When dealing with the ignition system a quick method of checkingthe battery is as follows: Switch on headlightsand ignition and operate the starter. If the engineis turned over at a reasonablespeedand the lights remain fairly bright, (they will dim slightly) we cao assumethat the battery will supply sufficient current for us to be able to carry out the ignition test procedure. Should the lights dim excessivelyand the starter appear sluggish, the complete test procedure must be applied to the battery (i.e. hydrometer and high rate discharge). Fig. 25 Checkingfor H.T. sparking TEST 2. Cbeck for H.T. Sparking This test is to ascertainwhethera good H.T. spark is beingproduced. Remove the main H.T. lead from the distributor cap and hold the end of the cable approx. 6 mm (0.25') from the engine block (see Fie. 25). Switch on the ignition, crank the engineand checkfor regular sparking. Ifregular sparkingoccurs,this suggestsa fault other than coil output, i.e. plugs, fuel system,timing etc., but if sparkingdoesnot occur, proceedwith following tests. CHECKING THE PRIMARY CIRCUIT TEST 3. Yoltageat '+' Terminalof Coil (ContactsClosed) '*' terminal A voltmeter is connectedbetweenthe of the ignition coil and a good earthpoint (for example, the engineblock or chassis),seeFig. 26. It is preferablefor the contactsto be closedduring the test, so that current is flowing through the primary winding. The igrritioo is tben switchedon. If the voltmeter registersthe samevoltage as the battery voltageunder load, i.e. ignition on, contactsclosed,it provesthat the supply from the battery to the ignition coil is satisfac- Fig. 26 Voltage at '+' terminal of coil (contactsclosed) tory. On the other hand, zero or low voltage indicatesa fault betweenthe battery feed and the '+'terminal iu wbicb casethis circuit must be checkedback to the source of supply. Note: All testsare for negativeearth systems. It shouldbe rememberedthat in a positiveearth system,the supply sideof the ignition coil is the '-'terminal. . P a g e1 6 Fig.27 Voltageat '-' terminal of coil (contactsopen) TEST 7. Checkingthe SecondaryCircuit The secondarycircuit is checked to ensure that sufficientvoltageis inducedin the secondarywinding to producea high voltagespark. One end of a known good H.T. lead is connectedin the H.T. outlet of the ignition coil. The other end is held approximately6 mm (0.25') from a clean area of the engineblock (Fig. 30). With the distributor contacts closed,the ignition is switchedon. The contacts are then flicked open and if a good strong spark is obtainedacrossthe gap for eachflick, it provesthat the ignition coil and capacitorare serviceable. If oo spark-occursuntil the 6 mm (0'25') gap is eithera faulty capacitoror weak reduced,this indicates output,proceedto next test. secondary : arth F i g .2 8 D i s t r i b u t o r e TEST 5. Distributor- Eartb If the last test has shown that the distributor is short-circuitedto earth, the following points in the 'L.T.'line shouldbe checked,seeFig.28. (a) ' - The lead betweenthe ignition coil ('-' terminal) and the distributorL.T. terminal. (b) flexible lead, connectingthe distributor L.T' The ' terminal to the moving contact (terminal post). (c) The flexible lead, connectingthe contact breaker terminal post to the caPacitor. (d) Also checkthat the tagson the endsof thecapacitor ' and flexible leads at the L'T. terminal Post are under the shoulder of the nylon bush, and not under the securingnut' (e) ' ' Finally, check that the capacitoris not earthed' This is' achievedby disconnectingthe capacitor from its mounting. '-'Terminal of Coil TEST 6. . Yoltageat (ContactsClosed) When all connectionsare re-made,the voltmeteris left connectedas in the previoustest, i'e. betweenthe '-' terminal and i good earth (Fig. 29). The coil contactpoints areclosedby rotating the -engine.When the ieniiion is switchedon, a zero readingshouldbe obtai-ned. If the voltmeterregistersa voltage,it is due to one of the following faults: l. Dirty or oilY contacts. 2, Faulty earth connection(i.e. betweenthe distributor shanliand the enginebloik, or the flexiblelead from the contact Piateto earth). Contactsnot closingProPerlY. 4. A high resistancein circuit from the coii to the C'B' on the distributor. ). Broken flexible lead betweenthe distributor L'T' terminal and the contact breakerterminal post' 6. Open-circuitcoil to distributor lead. TEST 8. Checkingthe Capacitor The capacitoris checkedby substitution. The o.riginalcapacitoris disconnected,and a test caoacitor. known to be serviceable,is connected beiween the distributor L.T. terminal and earth, as shownin Fig. 31. spark is Switch on the ignition. If an unSatisfactory obtainedwhen the contactsare flicked open, as in the previoustest,the secondary windingofthe ignitioncoil is faulty. However,if the spark is now improved,it showsthat the originalcapacitorwas not functioning satisfactorilv. Fig. 29 V o l t a g ea t ' - ' t e r m i n a l o f c o i l ( c o n t a c ccsl o s e d ) t h e s e c o n d a rcyi r c u i t F i g .3 0 C h e c k i n g Pagel7 Fig. 3l C h e c k i n gt h e c a p a c i t o r 3mm{O'125') Fig.32 C h e c k i n g! h e r o r o r a r m i n s u l a t i o n TEST 9. Checkingthe RotorArm Insulation Next, the rotor arm is checkedto ascertainwhether it is punctured,this wouldcausethe sparkto be earthed on the cam-head.However,as the Duncturesare invisible to the naked eye, the following method is adopted. An H.T. lead is connectedin the chimnevo[ rhe ignition coil and the other end is hcld approi. 3 mm (0.125")from the rotor arm electrodeas shown in Fig. 32. When the ignitionis switchedon, the contacts are ffickedopen. If thereis a spark,it provesthat the rotor arm is earthedon the cam-head.The rotor arm should,therelore,be replaced. (The H.T. spark referredto shouldnot be confused with the faint sparking.due to electrostatic chargeand leakage). P a g e1 8 DISTRIBUTOR COVER AND H.T. LEADS (Fig. 33) T h e d i s t r i b u t ocr o v e rs h o u l db e t h o r o u g h l yc l e a n e d , inside and outside, with a soft, dry cloth, paying particularattentionto the.space betweenthe electrodes. Ilthe coveris "tracked"(shownby a thin, conducting track of burned bakelitebetweenthe electrodesor to earth),it shouldbe replaced. The condition of the H.T. cables,especiallythe i n s u l a t i o ni,s t h e nc h e c k e d . When the insulation shows siens of crackine or -care perishingthe cablesmust be reniwed. Special must be takento maintainthecorrectfiring orderwhen replacing theH.T. cables. BALLASTED IGNITION SYSTEM H,T,LEADFNOM corL / PLUG H.I LEA| Fig.33 C h e c k i n gt h e d i s t r i b u t o r c o Y e ra n d l e a d s CONTACT BREAKERASSEMBLY AND GAP SETTING (Fig.3a) The contact breaker must be maintained in good condition. Ensure that the contact surfacesare free from oil and grease. If the contacts show signs of excessivewear, they should be replaced. Ballastedignition.systems(lig. ]0) are usedto improve engine starting especiallyin very cold conditions,and alsoto providemaximumspark efficiency at high enginespeeds. Battery voltageis at its lowestwhen the engineis being cranked. This drain on the battery causesthe terminal voltageto fall well below its normal value. during startingthe H.T. spark is obConsequently, tainedfrom an ignitioncoil which is operatingfrom a reduced voltage. In these conditions the ignition performanceis usually satisfactory,but in extremely to usea systemin which cold conditionsit is preferable the voltage appliedto an appropriatecoil remains constant. A ballast resistoris connectedin serieswith the ignition coil primary winding, and the circuit is arrangedto short out the resistorwhen the starting motor is operating. The ballast resistornormally comprisesa coil of resistivewire housedin a porcelainblock with electrical connections by meansof'Lucar' connectors. The ballastresistoris clampedto its fixing (often an ignition coil mountingbolt) by a bracketsurrounding the porcelainblock. Note: The resistormay take the lorm of a resistive cableon someapplications. The cold starting performance is improved by permitting the ignition coil to operate at a voltage slightly above its normal operatingvoltage. Slight overloadingis not detrimentalto the coil as it occurs only while the engineis beingcranked. 0.015"GAUGE When settingthe contactbreakergaPensurethat the contactsare fully open (i.e. the contact heel is on tbe peak of the cam t6Ue). e gauge of the appropriate shouldmake mm (0'014'-O'016"), ihickness.0'35.-0'40 a slidine fit betweenthe contacts. It is advisableto recheck t6'egap after adiustment,to ensureno movement has taken;hce while the screwwas beingtightened. Providing the distributor is in good mechanical condition,in alternativemethodof settingthe contact gap is to usean accuratedwell anglemeter. C O N T A C T B R E A K E RA D J U S T H E N T F O R 35D DISTRIBUTORS F i g . 3 4 C h e c k i n g c h e c o n t a c t b r e a k e r a s s e m b l ya n d 8 a Ps e r E r n g The contactbreakersettingis adjustedby rotating stud which Protrudesthrough the the hexagon-shaped distributor body. It is adjusted to give the correct dwell angle(contactclosedperiod),seeFig. 35. Adiustmentshouldbe carriedout usinga dwellmeter set with ihe enginerunning. The dwell angle-should.be within the limits specifiedby the manufacturer. The hexason-shapedstud is screwedanti'clockwiseto increasi the dwell angle(closethe contactpoint gap)and the dwell angle(openthe contact clockwiseto decrease cap). Note: Static and strobosccpictiming are describedat the end of the chaPter. r d i u s t m e nf to r 3 5 D F i g . 3 5 C o n t a c tb r e a k e a distributors Page19 IGNITION SWITCH AMMETER BATTERY IGNITION cotL Fig. 36 Typicalballasted ignicionsysrem The primary windiog of an ignition coil (usedwith a ballast resistor) has a lower inductancevalue, which permits a more rapid build up of the magneticfield as thl: contact points close. There is also less heating effect inside the coil as the ballast resistor itseF dissipatessomeof the heat producedin the circuit. TEST l. Voltage at '+' Terminal of Coil @allasted System)- (ContactsClosed) To obtain a good H.T. spark it is necessary to havea good voltagesupply to the coil. TO IGNITION SWITCH to TO O{STRIBUTOB F l g . 3 7 V o l t a g ea t ' a ' c e r m i n a lo f c o i l ( c o n t a ect sl o s e d ) Page 20 Connect the voltmeter(Vl) betweenthe '*' tetminal of the coil and a good earth, as shown in Fig. 37. The sontactsshould be closeddurine the test to enablecurrent to flow through the primar! winding. Switch on the ignition and the voltmeter should lggister approx. 6V for a 12 volt ballasted system. If the correct voltageis indicated,the supply frdm the battery to the ignition coil is satisfactory.Next, temporarily earth the coil negativeterminalind crank the engineby the starter,'any increase in thevoltageindicates a satisfactory circuit. A slight decreaseindicates a faulty solenoidswitchor leadfrom the solenoidswitch. Removetemporaryearth connection, If no readingsare obtained,proceedwith the Tests2 and 3. If correct readings or battery volts are obtained, proceedto Test 4. TEST 2. Yoltageat '+' Side of BallastResistor With the cootactsclosed,connectthe voltmeter (V2) betweenthe feedside ofthe ballastresistorand a gbod earth (Fig. 38). On applicationswith resistivesupply cable, conncct the voltneter betweetr the ienition switch end of the cable and a good earth. If 6attery voltage is registered,proceed to Test 3. But if no voltageis indicated,checkback aloug supply cable. TEST 3. Yoltage at CoiI Side of Ballast Resistor Connectthe voltmeter(V3) betweenthe coil side of the ballast resistorand a good earth (Fig. 38). The ignition is.switchedon. No readingindicatesa faulty ballastresistor. TEST 4. Voltageat '-' Termiualof Coil (ContactsOpen) With contactsopen, conoectthe voltmeter betweeo the coil '-ve' terminal and earth as (V4) io Fig. 39. With ignition on, voltneter shouldreadbaitery voltage. No readingiudicatesopen-circuitcoil primary windiag or short-circuiton the lead from the coil to distributor or within the distributor. Fig: 38 Voltage at ballastresistor Repeat test with coil '--ve' lead disconnected;if readingnow appears,fault is on distributoror lead. No reading- faulty coi.. TFST 5. Distributor - Eartb If the last testhasshowntbat the distributoris shortcircuited to earth, the following points in the L.T. line should be checked,seeFig. 40. (A) The lead betweenthe ignitioncoil ('-ve' terminal) and the distributor L.T. terminal. (B) The flexiblelead, connectingthe distributor L.T. terminal to the moving contact(terminal post). (C) The flexible lead, connectingthe contact breaker terminal post to the capacitor. (D) Also, checkthat the tagson the cnd of the capacitor and flexibleleadsat the L.T. terminalDostare under the shoulder of the nylon bush, ind not under the securingnut. (E) Finally, check that the capacitor is not earthed. This is achievedby disconnectingthe capacitor from its mounting. Fig. 39 Voltageat '-' termlnalof coll (contacts open) TEST 6. Voltageat 1-' Terminal of Coil (ContactsClosed) When all connectionsare re-made,the voltmeteris left connectedas in Test4, (i.e. betweenthe coil '-ve' terminal and a good earth) (Fig. 41). The contact points are closed by rotating the engine. When the ignition is switched on, a zero reading should be obtained. If the voltmeterregistersa voltage,it is due to one of the followinglaults: l. Dirty or oily contacts. 2. Bad earth connection (for instance, between the diskibutor shank and the engine block, or the flexible lead from the contact plate to earth). 3. Contactsnot closingproperly. in the circuit from the coil to the 4. A high resistance C.B. on the distributor. 5. Broken flexible lead between the distributor L.T. terminal and the contact breaker terminal post. 6. Open.circuitcoil to distributor lead. Testsfor the secondaryH.T. circuit are identicalto those for conventionalsystems,as describedin the previoussection. Note: Static aod stroboscopictiming is describedat the end of this chaoter. Fig. {1 Voltagear '-' lermlnal of coll (contacts closed) Pzgc2l tacho ignition sw start- I :::rr'- amplifier ballast unit starter solenoid o lniti coil battery e !7 F i g . 4 7 T y p i c a'lO P U S s' y s r e m INTRODUCTION The "OPUS" (Oscillatingpick-up system)Fig. a2. is a fully-electronic systemwherethe distributorcam and contactbreakerassemblyhave beenreplacedby a pick-up moduleand rotatingdrum carryinga number of ferrite rods, one for eachenginecylinder. As each rod passes in front of the modulea smallvoltagesignal is generated by lhe modulewinding,this signalis then transmitted to the amplifier. The transistorised circuitsin theamplifierunit will instantlyswitchoff the current in the ignition coil primary winding, thereby producingan inducedcoil secondaryvoltage(i.e. the 'spark'). The iguition coil used is a speciallow-inductance type designedfor high speedoperationand as suchis particularlysuitablefor 8- and l2-cylinderengines. As no contactsare used, the problem of contact breakerbounceat high speedis non-existent. OPUS IGNITION TEST PROCEDURE TEST l. Battery - Rapid Check(Fig. a3) Switch on Jhe headlightsand ignition and operate the starter.If the engineis turnedover at a reasonable speedand the lights remain fairly bright (they will dim slightly),we can assumethat the battery will supply sufficientcurrentfor us to be ableto carry out the t-est procedure. Should the lights dim excessively and the starter appearsluggishthenthe completetest proceduremust be appliedto the batteryas in the battery sectionof this book. lgnition Switch On Ammeter aa, tr{'\) E\\ ST\ STA l t \ \ \ \./ Lighting Switch On Fig. 43 B a t t e r y- rapidcheck TEST 2. Check for Sparking Connecta test H.T. lead into the coil chimney(remove vehicleH.T. lead)and hold the free end approx. 6 mrn (0.25') from the engineblock, as shown il fig. A A With the ignition on, crank the engine. Regular sparkingshouldoccur. If no sparkingoccursproceed with testsin sequence. If sparking occurs,carry out Test 3a only, then proceedto Tests9 and 10. Page22 Fig, 44 Checkingfor sparking WarningLight o ' 9 o h mI l o z OHMMETER 2'5ohm t lOz 0.020'-o'022' ( AIRGAPCHECK Fig. 45 C h e c k i n gc h e d i s c r i b u t o r p i c k - u p m o d u l e Test 3. Distributor Pick-up Module ( a ) M o d u l e a i r g a p- R o t a t et h e e n g i n es o t h a t t h e ferriterod markedNo. I cylinderon Jaguaror the rod immediately under the rotor electrodeon A s t o n M a r t i n , i s i n l i n e w i t h t h e p i c k - u pm o d u l e , seeFig. 45. T h e g a p b e t w e e nm o d u l ea n d t i m i n g r o t o r s h o u l d be a parallel0.5H.55 mm (0.020"-0'022").Ii inmodulefixing screws. correct,adjustby slackening (b) Disconnectthe distributorto amplifier plug and on the distributorside,usean ohmmetefto check valuesbetweenthe centreand each the resistance outer terminal. The readingsshould be: Centre terminalto outerterminalwith red cable2.5 ohms Ll|%, centre terminal to outer terminal with black cable 0.9 ohm +107i. Leave plug disconnected. F i g . 4 . 6 C h e c k i n gb a l l a s cr e s i s t o r ( 9 B R ) TEST 4. Check Ballast Resistor(9BR) Withdraw socketat amplifierside of ballastresistor. Connectthe voltmeterbetweena good earth and each terminal of the ballastresistoras shown in Fig. 46. Caution:Ensurethat the voltmeterprod doesnot touch the resistorhousingwhile in contactwith the terminals. W i t h i g n i t i o no n , r e a d i n ga t e a c ht e r m i n a sl h o u l db e batteryvoltage. I f z e r o r e a d i n go n a l l t e r m i n a l s c, h e c k s u p p l y a t S.W. terminal (otherside of ballast)and if zero here. tracecircuit back via ignitionswitch. If zeroreadingon one or two terminalsonly, replace ballastunit. TEST 5. Voltageat Coil '+ve' Re-connectamplifierto ballastsocket. Connectvoltmeterbetweena good earthand the coil '*' terminal (Fie. a7). With ignition on, the reading should be 4-6 volts. A high readingindicatesa faulty coil or amplifier; proceedwith tests. Zero readingindicatesa fault in the amplifierto coil '*'lead. F i g .4 7 V o l t a g ea t ' + ' t e r m i n a lo f coiI Page23 TEST 6. Voltage at Coil '-ve' (Open-Circuit) '-' terminal. Disconnectlead at coil Coonect the voltmeter between a good earth and coil '-ve' as shown in Fig. 48. With iguition ON, meter should read BATTERY VOLTAGE. Zero readiogindicatesthat the primary winding of the coil is faulty. TEST 7. Voltage at Coil '-ve' (CloseilCircuit) Re-coonectlead to coil '-' terminal,leavevoltmeter connectedbetweenearth and coil '-' (Fig. a9). With ignition on, meter should read G-2V. If reading is battery voltage the amplifier is faulty and sbould be replacedtogetherwith pick-up module. If-readingis above2 vglts but belonrbatteryvoltage, check volt drop on amplifier earth coonectionby connecting_voltmeter betweenamplifierhousingand a good earth. With ignition on, voltmeter should show 0.5V maxinum. If higher, amplifier has a bad earth conoection. TEST 8. Amplifier Switching Re-conoectamplifier/distributor socket. Connect voltmeter betweena good earth and coil '-' terminal (Fig. 50). With test H.T. lead connectedin coil chimney hold free end 5 mm (0.25") from the engineblock. Swilch on ignition_andcrank engine,voltmeterreadingshouldbe 3-4V, fluctuating with regular sparking lrom H.T. lead. . A fluctuatingvoltrgeter readingwith no H.T. spark ind-jcatesa faulty coil secondarywinding, replace-the coil. If voltmeterstaysat low reading(below 2V) with no spark, amplifieris faulty, and should be replaced. Fig. 49 Voltage at coil '-' terminal (closed circuir) Fig. 50 Checkingthe amplifierswirching TF.ST 9. Rotor Arm Insulation Hold free end of test H.T. lead approx. 3 mm (0.125')-frgm.centre of rotor arm electroi6,seeFig. 5L Switch_ignition on, craok engine. No spark sh--ould orcur. If a ggod spark occurs replace the rotor arm. (A good spark should not be confused with the verv faint sparking that may be seen due to electrostatii chargeand leakage). TEST 10, Dishibutor Cover and H.T. Cables (Fig. s2) The distributor cover should be cleanand drv. The H.T. carbon brush must be free to move in its holder. If the distributor cover electrodesare badly erodedor tracking has occurred,a new cover should-befitted. Carry out test for sparking using vehiclemain H.T. lead insteadof test lead, if no spark,lead is faulty. Fig.51 Checking the rororarminsulation )P.'t CAFEONEFIUSH Fig. ,18 Voltageat coll '-' terminal(opencircult) Page?A Fig.52 ChecklngshedlstrlbutorcoverandH.T.cabler If spark occurs re-fit distributor cap and all leads. Eneinl should now fire. Misfiring on individual cyli-nderscould be due to a faulty H.T. lead (to that plrticular cylinder) or spark plugs. IGNITION TIMING After checking the ignition system, ensure the ignition timing is in accordancewith the manufacturers' recornmendations. Two suitablemethodsare shown(a) Static Ignition Timing. (b) StroboscopicTiming. S T A T T CI G N I T I O N T I H I N G Rotat€ the engine until No. I piston is just before T.D.C. on the compretsionstroke, see Fig. 53. (exact position as specifiedby enginemanufacturer). At this iioint the rotor arm shouldbe pointing to the djstributor iap segment connected to No. I spark plug. The contaci breaker points should be just at the point of ooenins in the direction of rotation. This can be virified by connecting a voltmeter between the distributor L.T. terminal and a good earth. At the precisemoment the contactsopen ttle_voltmeterwill iegister battery voltage. Should the ignition timing be iniorrect, centralisethe micrometeradjuster(if fitted), slacken the distributor clamp bolt and position the distributorto the point of contactsabout to openand re-tightenclamp bolt. It must be rememberedan incorrectcontactgap can affect ignition timing. The contactsmust be set and maintainedat 0.35-0.40mm (.014"-.016'). The ignition timing is now set with sufficient accuracyto be able to start aod run the engine. Final adjustmentmay be carriedout using the stroboscopic timing light and the micrometeradjustment. s T R o B o s c o P l cT I M I N G( F i gs. a ) Connectthe strobeH.T. pick-up into No. I plug lead and disconnectthe distributor vacuum pipe. In the caseof a separatestrobe,battery supply will also be required. Start and run the engine at the manufacturer's specifiedidling speed. Direct the strobe light on the timing marks aod checkthe degreesof advanceagainst the recommendedfigures. The strobe light can also be used to check that the centrifugal and vacuum advance mechanisms are operating,but in order to do this, the figuresobtained must be comparedto thosespecifiedfor the particular vehicie. Thesefiguresare quoted in the enginemanufacturer'sworkshopmanual. Timing marks and their positionswill vary with different typesof vehicles.Theseare normally quoted information. in the vehiclemanufacturer's STATICTIMING -.--n \€l9l \iw . |5 to' f ) ::lii: i.i:l: Fig. 53 S t a t i ci g n i t i o n t i m i n g Fig. 54 S t r o b o s c o p i ct i m i n g Pagc25 DYNAMOSAND CONTROLBOXES INTRODUCTION The D.C. chargingsystemis designedto maintain the battery in a reasonablestate of charge under averagerunningconditions. This means that the dynamo output must be sufficient to supply the normal continuous vehicle electrical.loadplus the little extra requiredto keep the battery charged. The inherentdesignof the dynamo is such that it must alwaysbe under some form of control, both to protect thc machine against overload and to protect the batteryagainstovercharge. A controlbox, therefore,is designed to operatewith a specifictype of dynamo on a given appliiation. VoltageControl" - For manyyearsthe "Compensated (2-bobbin)systemhas beenemployed,and in fact is still used on certain present-day productionvehicles. However, with the increasein electricalequipment fitted to the modern vehicle,it becamenec"ssirv to utilise a xylte4 better suited to present-dayrequirements. This brought about the "Curreni Voltase Control" (3-bobbin)-system.The main advantage6f this systemis that it allowsmaximumsafedynamo outpu!.fgr a longer period of time when the batt'-.-yis in a dischargedcondition. Dynamos or control boxes may be replaced as individual units provided two rules are stiictly observed. l. That the correctreplacementunit is fitted. 2. That, after fitting, the test procedureis carried out on both units to ensurethat the completesysternis operatingefficiently. Page26 TEST f. Battery Test Using a hydrometer, check that the battery is at leastT0l chargedand in good condition, seeFig. 55. A battery fault can have an adverse effect on the charging syst€m. for example,a sulphated battery will producelow chargerate whereasabattery with i shortedcell will producehigh chargerate. CHECKING DYNAMO TEST 2. Drive Belt Tension - Allow 13-19 mm (0'5'-0.75') play when moderate lnger pressureis appliedto the lohgestrun ofthe belt, Fig. 56. The dynamo will not chargethe battery if the drive belt is too slack. On the other hand, an excessively tight belt will damagethe bearings. If the beit is worn or oily it shouldbe replaced. 1.110-1.130 1'230-1.250 Fig. 55 Hydrometertesr ..::.// ,'.'13-1g^^ (12-9q'l t'.\ ,i,' ,// 'r, /,/ F i g .5 6 D r i v e b e l tt e n s i o n TEST 3. Testing the Armature Circuit the Disconnectthe leadsat the dynamo and connect'D' voltmeter betweena good earth and the dynamo terminal,Fig. 57. Start the engineand slgwly increase the speedto approx. 1,500rev/min. The voltmeter shouldregisterl'5-3'0V. TEST 4. Testingthe Field Circuit position as for the The voltmeteris kept in the same 'D' and an orevioustest (betweenterminal 'D' and earth), 'F', Fig' 58. and i,mmeter is connectedbetween The eneinespeedis increasedslowly,until the voltmeter reeisteri nominal battery voltage (usually l2V)' The arimeter should then read approx. 2AIf the ammeter indicatesa higher current, -t.hefield is low' resistance F i g . 5 7 T e s t i n gt h e a r m a t u r e c i r c u i t F i g .5 8 T e s t i n gc h ef i e l dc i r c u i t TEST 5. CheckingDynamoLeads If the correctreadingsare obtainedon the testsat the dynamo,the fault could be in the wiring between dynamoand control box. To provethesecables,testas the leadi at the dynamoand disf6llows: Re-connect 'D' and 'F' at the control box. Connectone connect 'D' lead, leadof the voltmeterto earth,the other to the The readFig.59,and run theengineatchargingspeed. dynamo(l'5ine shouldbe the sameas at'D' on the 'D' lead,a high :'dV). No readingindicatesa faulty the'D' and'F'cables. readingindicatesa shortbetween leavevoltmeter in position If the readingis correct, ('D' to earth) and short 'F' lead to 'D' lead. VoltIf the meterneedleshouldrisewith increasingspeed. 'F' only slightly,an open-gircuit lead readingincreases i s i n d i c a t e d .A z e r or e a d i n gd e n o t e s ' F ' l e a ds h o r t e d to earth. COMPENSATED VOLTAGE CONTROL TEST 6. Open-CircuitYoltageSetting 'D' and 'F' leads to control box. Re-connect R e m o v et h e ' A ' a n d ' A l ' l e a d sa n d j o i n t h e t w o t o sether (Fie. 60). Connect the voltmeter between 'D' and earth, and run the engineup until ierminai voltmeter settles. Increasespeed slightly and then regulationshouldtake placewithin the limits: l6 to t 6.5V. If the voltmeterreadingsafe outsidethe apPropriate limits,the voltagesettingmust be adjustedby turning screwat the backof the regulatorframe. theadiustment Turn ihe screwclockwise(or inwards)to increasethe (or outwards)to reduceit. voltage,and anti-clockwise lf iurning the adjustmentscrewhas no effecton the voltagesetting (readingoff the scale),check for a or an open-clrcult faultycontrol box earthconnection, s h u n tw i n d i n g . Fig.59 Checking Page27 . OPENCIRCUIT VOLTAGE SETTING F i g , 6 0 C h e c k i n gt h e o p e nc i r c u i tv o l t a g es e r r r n g TEST 7. Cutting-inYoltage -..N.lt, the cutting-in voltage must be checked(Fig. 6l). Connectan ammeterbetweenthe control boi .A' lerminal and the leads which have been disconnected from the 'A' and 'Al' terminals.The voltmeteris keot in the same position, betweenthe 'D' terminal and earth. Switch on headlights. Start the ensine and graduallyincreasethe speed. When the cut-out pointsclosethe voltmeterneedle will kick back. This should occur within the [mits 12.7-13.3V.If it doesnot, the cur-outsettinsshouldbe adjustedby meansofthe adjustingscrewat fhe back of the cut-out. Adjust with engineslationaryand repeat test. . Increase the engine speed. The ammeter reading should.increasewith speed. (The actual reading wil'i d-epend-o-ntle stare of the battery charge ani the electricalload). V o l t a g ed r o p o n r h e s u p p l y Page28 CUTTING IN VOLTAG€ Fig.61 Checking t h e c u t c i n g - ivno l r a g e Gradually reducethe enginespeed. The ammeter needle should fall until it indicates a discharge (or reverse)current of 3-5 amps. The ammeter ueedle should return to zero when the cut-out points open. Replaceall control box leads, ensuring correct connections. TEST 8. CheckingVoltageDrop on Supply Line Removethe 'D' lead from the dvnamo terminal and connectthe ammeterinto the circriit, seeFig. 62. Connectthe voltmeterbetweenthe dyaamo 'D'lead (removed)and the batterysupplyterminal'atthe starter solenoid. Start and run the engineat chargingspeeduntil the ammeter reads l0A. At this point the voltmeter readingshould not exceed0'75V. A higher reading than 0.75V denotesa high resistance in the insulatedcircuit. IGNITION WARNING LIGHT The "Ignition Warning Light", to use its more popular name, has two basicfunctions. Primarily,to indicatethat the ignitionis switchedon and secondly,when the engineis started and the rev/ min increased,it should fade and "go out". This indicatesthat the dynamo voltagehas risensufficiently to close the cut-out switch betweendynamo and battery. Note: The fact that the light goes out does rot necessarilymean that the charging systemis functioning correctly. One side of the bulb is connectedto the output terminal of the ignition switch and the other side to 'D' terminal, usuallydone at the control box 'D' the terminal,as shownin Fig. 63. With the'ignition on and the engine stationary, battery voltageis appliedto one side of the warning light via the ignition switch. The other sideis connect6d to earth via the dynamoarmatureand brush-gear. Whenthe engineis startedand therev/minincreascd, voltagefrom the dynamo 'D' terminal risesat one side of the bulb to opposebattery voltageat the other side. The warning light theq fades until both voltagesaie equal, when it is completelyextinguished.At almost the same instant the cut-out points close (l3V) thus shortingout the warninglight and allowingthe bulb to remainout. A warning light that "glows" faintly under normal runningconditionscan be due to any of the following faults. in the ignition switch. l. Internal high resistance 2. Dirty control box cut-out contacts. 3. A slippingfan belt (if slippingbadly enough). I o.c. A m b i e n lt - V o l t a g e I TemperatureI Checking 0"-25'C | 1 4 . 5 - 1 5 . 5| lf ln.r., Between I to 1 4 . 0 - 1 4 . 5| 14.5 ( 3 2 ' - 7 7 " F ) l l 1 5 . 5 - 1 6 . 0 l r s . s 26'-40"C I t4.25-t5.25 | tl.lS-tq.ZS| rc.Zs (78'-104'F)l 1 1 5 . 2 5 - 1 5I .1755. 2 5 TEST 2. Cutting-inVoltage The cutting-involtageis checkedasshownin Fig. 65. Connectan ammeterbetweenthe 'B'leads and the 'B' terminalon the control box. Keep the voltmeterin the samepositionas the previoustest (betweenterminal 'D' and earth). Switchon headlights.Start the engineand graduallyincreasethe speed. When the cut-outpointsclose,the voltmeterneedle will kick back. This should occur within the limits 12.7-13.3Y . If it doesnot, thecut-outsettingshouldbe adjustedby meansof the adjustmentscrewat the back cf the cut-outframe(6GC) or specialtool (R8340). B B3 4 O V O L T A G ER E G U L A T O R SETTING Fig.64 Checking the voltage regulator serring F i g . 6 3 l t n i t i o nw a r n i n gl i g h tc i r c u i t R8340 CURRENT VOLTAGE CONTROL TEST l. VoltageRegulatorSetting 'B' terminal(if morethan Removethe leadsfrom the one,join them together). 'D' terminal and Connecta voltmeterbetweenthe earth,(Fig. 64), and run the generatorup to a stable unning speed,normally about 3,000rev/min. If the voltmeterreadingsare outsidethe approplrate limits, the cover must be removed and the voltage regulatorsettingadjustedby meansof the specialtool. A reguiator checkedand found to be stable at not morethan 0.5V aboveor belowthe checkinglimits (see table) must be re-setto the nearestoutside limit (high or low). If the settingis more than 0.5V outsidethe limits, the regulator can be considered faulty and should be replaced. The regulator must be adjusted by means of the specialtool. Note: Boxesunder warrantyshouldbe replaced. CUTTINGIN VOLTAGE Fig.65 Checking the cutting-in voltage Page29 Increasethe engine speedand the reading on the ammetershould increasewith speed,(dependenton stateof battery chargeand electricalload). Gradually reducethe enginespeed. The ammeter needleshould fall until it indicatesa discharge(or reverse)current of 3-10 amps. The ammeterneedle shouldreturnto zero when the cut-out points open, TEST 3. Current RegulatorSetting(Fig. 66) For thepurposeof this testthedynamomustproduce its safe maximum output regardl4s of the state of chargeof the battery,thereforethe voltageregulator must be madeinoperative. This is achieved by connectinga crocodile clip acrossthe voltageregulatorcontacts. Switchoff all lights (from previoustest). With the ammeter still in position (connectedin serieswith 'B'lead) start the engineand increasethe rev/min to just abovechargingspeed. The meter readi^ngshouldcorrespondto the figureshownin the table lot a grvenclynamo. Associated dynamo C40ll (4r" dia. fan) C40/l (5" dia. fan) C4OA C4OL c42 C40T(exceptPart No. 22762) C40T(PartNo. 22762) Still with the headlightson, start and run engine at abovecharging speed,check ammeter reading. If incorrect to specificationsquoted,replacebox. F i g .6 6 C h e c k i n g c h ec u r r e n tr e g u l a t osr e t r i n g 1a TEST 4. CheckingVoltageDrop on Supply Line Removethe 'D' lead from the dynamo terminal and connectthe ammeterinto the circuit,seeFig. 67. Connectthe voltmeterbetweenthe dvnamo'D'lead and the battery supply terminal at the siarter solenoidStart and run the engineat chargingspeeduntil the ammeterreadsl0A. At this Dointthe voltmeterreadi n g s h o u l dn o t e x c e e d 0.75V.' A higherreadingthan 0.75Vindicatesa high resistancein the insulatedline. l8A CONCLUSION N o m i n a lS e t t i n g :E I amp r9A 22A 10.5.A 25A 30A Methodof adjustmentis similarto voltageregulator and cut-out. In the caseof boxesunder warranty wherethe cover should not be removed, the following alternative methodsof checkingmay be used. Switch on headlightsand leaveon for 5 minutesbefore startingengine. Having obtainedan idea of the various forms o f generatorcontrol units and their working, it may be desirableto add a note of caution. The successfulservicing of these important componentsdependson making adjustmentswhich are stableand permanent.Only a limitedamount of work can be successfully executedin the generalgarage. If, for example,a control unit will not respond to the adjustments outlined,it shouldbe replaced. FB34O BATTERY Fig. 67 Page30 V o l t a g ed r o p o n t h e s u p p l y l i n e ALTERNATORS INTRODUCTION currentwhich is The alternatorproducesalternating. convertedto direit current before being connectedto the vehicle electrical system. In this respect the alternator'.anddynamo are similar, sincethe current in the armaturewindingsof the dynamois eenerated ilso alternatingcurrentwhich has to be convertedto directcurrent deforeit can be usedto charsethe vehicle battery. In the caseof the dynamo,the alternatingcurrentis rectified bv meansof a commutator and brush-gear' The output of the alternator is rectifiedby semiconductor devices,which allow electricity to flow in one direction only - and so supply uni-directional current to the vehicleelectricalsystem. The alternator outPut is controlled by a voltage reeulatorwhich is completelyelectronic,having no viSrating contacts. The use ol printed circuits and devicesmake this type of regulator semi-conductor more reliableand more stablethan the conventional regulatorusedwith dynamos. type of mechanical No cut-outis requiredwith this type of controlsince devicesprevent reversecurrents the semi-conductor of the from flowing. AIso,theself-regulating Properties alternatorlimit the output curren! to a safevalueso that there is no needfor a currentregulator. The latest alternators represent an. inrportant developmentin design,as the alternatorand voltage regulaior are combinedto form a single unit, the resulator being housedwithin the end cover o[ the the chargingcircuitwithout aliernator.This simplifies changingthe operatingprinciples. Alternator designand constructionallows a wider speedrange and utilisationof higher pulley ratios' whictr in iurn enablesthe battery to be charged at lower enginespeeds.This can be beneficialin high densitytrafficconditionsand on modernvehicleswith high electricalloads. 1 . 1 1 0 - 1 . 1 3 0DISCHARGED 1-230-1.250 TOZCHARGED 1.270-1.290 CHARGED Fig. 68 Hydrometertest Page3l ln this sectionwe shalldiscussthe testprocedurefor two typesof A.C. system: l . T h e b a t t e r y - e x c i t e, m d a c h i n e( l O A C a n d l l A C ) , wherethe alternatorfielddepends on the battery,via a relay, for its initial excitation. Consequenilv. a flat battery would result in no chargeeven if'the vehicleis startedby towing, which is possiblewirh a Dieselengine. machine(the AC and ACR range), 2. The self-excited where,although some excitationis providedfrbm the batteryvia the warninglight this is not essential as the machineis capableof supplyingits own field circuit when driven fast enough. The difference betweenan AC and ACR systemis that the former usesan externalregulatorwhilst the ACR has its regulatorincorporatedin the machine. TEST l. BatteryTest Using a hydrometer,check that the battery is at l e a s t7 0 \ . c h a r g e da n d i n g o o dc o n d i t i o ns, e eF i g . 6 8 . A battery fault can have an adverseeffecton the charging system. For example,a sulphatedbattery will producea low chargerate while a batterywith i shortcdcell will producea high chargerate. TEST 2. Drive Belt Tension A l l o w l 3 - 1 9 m m ( 0 . 5 ' - O . 7 5 "p)l a y w h e n m o d e r a t e finger pressureis applied to the longestrun of belt. SeeFig. 69. The alternatorwill not chargethe batteryif the drive belt is too slack. On the other hand, an excessively tight belt may damagethe bearings. lf the belt is worn or oily, it shouldbe replacedwith a premiumgradetype. TEST 3. Connections E n s u r et h a t a l l l e a d sa r e i n p o s i t i o n . TEST 4. Checking6RA Relay The purposeof the 6RA relayis to de-energise the alternatorfield winding,whenthe engineis statlonary. The relayis connectedto the ignitionswitchso that it operatesonly when thc ignition is switched'on'. The rotor field is completedby contacts'Cl'and 'C2'. The alternatorwill not chargethe battery if the relay contacts lail to close. F i g .5 9 D r i v eb e l rr e n s i o n (a) With the enginestationary,disconnectthe battery earthcableand connectan ammeterin the alternator main output lead as shownin Fig. 70. ( b ) R e m o v et h e c a b l e sf r o m t e r m i n a l s ' C l ' a n d ' C 2 ' at the relay and link together. Re-connectthe batteryearthcable,'switch on the ignition and run the engineat 1,500rev/min. (c) If lhe ammeternow showsa charge.the previous lailure was due to the relay, oi its asiociated wiring, connections etc. (d) Connect voltmeter across 'Wl' and 'W2'. The voltmeter should read battery voltage if the relay has.agood earth and supply. If no reading,proceedto (e). (e) Check relay earth connectionby connectingthe voltmeterbetween'Wl' (white lead) and a good earth. The voltmeter should read battery voltaee. If not, check that the supply lead (vii igniti6n srvitcb)and its connectionsare in good condition. Note: Some vehiclesare fitted with a pressureswitch in the relay earth lead. Conneit a temporary to ignition s-witch trom battery Fig. 70 C h e c k i n g6 R A r e l a y Page32 to regulatof C h e c k i n g1 6 R A r e l a Y 'W2' on the relay and lead betweenterminal readsbatteryvoltage' now .".ttt. tf voltmeter the pressureswitchis probablyfautty' TEST 5. Checking15RA RelaY The l6RA relay is checkedin a similar mannerto 3-ia. The vaiiouschecksare shownin.Fig' 7l' tne "'Conni.t u.meter in the main charginglead to the batterY. 'Cl' and 'C2' and link to(a) '-' Remove connections voltmeter between ? Connect (Fig. la). littt". ' W l ' a n de a r t h . ' R u n a l t e r n a t o ra t c h a r g i n gs p e e d( 1 , 5 0 0e n g i n e rev/min). Ammetershouldnow showa chargeand the voltmeter6-8V. l l t h e a l t e r n a t o rs t o p s c h a r g i n gw h e n N o t e : l . 'Cl' to the and 'C2' are re-connected relay,proceedto Test (b)' 2. Il ammeterindicatesa chargebut voltmeterreadszero,proceedto Test(c)' (b) The foltowingcircuit checksnrrrstbe carriedout beforecondemningthe relaY. n e f o l l o w i n gp o i n t s : C o n n e cvt o l t m e t e i b e t w e et h Resu/ts ( i ) ' C t ' a n d e a r t h( F i g ' 7 l b ) - l Y s t e mv o l t a g e ' C I a n d ' W 2 ' ( F i g .7 l c ) - S y s t e mv o l t a g e tiii 1 1A C C h e c k i n gf i e l d c i r c u i t Page33 l4tithignition switchedon (i) 'R' and earth(Fig. 7ld) - Systemvoltage (ii) 'C2' and earth (Fig. 7le) - Approx. 2 volts (c) Removc'AL' lead at alternatorand connectvoltmeterbetween'AL' terminaland earth(Fig. 7li). Run engineat chargingspeed. Voltmeter should read 6-8V (l2V systems)or l,l-l5V (24V systems). If metershowszero reading,replacealternator. TEST 6. CheckingField Circuit Disconnectleadsfrom the voltageregulatorand tink 'F' t_ogether and '-' terminals,using an ammeter, F i g . 7 2 . ( I f l 6 R A i s u s e d ,c o n n e c t e r m i n a l s' C l ' a n d 'C2'). With the ignition 'on' rhe ammetershouldread approx.3,A. Note: Ifthere is no reading,connecta voltmeteracross alternatorfield terminals.Closeignition,if the voltmeterreadsbattery - voltagetheie is a fault in the alternator field. No rJadine indicatesa wiring fault between the alterna-torfield terminalsand the relay or regulator'F' terminals (on positiveearth checkearth fly-lead). TEST 7. CbeckingAlternatorMaximum Output Short out 'F' and '-' and connectthe ammeterin the main output lead at the alternator or starter solenoid,as shown in Fig. 73. Run thc enginc at should lPProx. 3,000rev/min. The ammeter.reading be: Alternator Model I Ammeter Readine loAc l rAc | I :sa cse | | z:a r rAc (23580) (23633) I IAC (24V) I 60A A zero or low readingindicatesthat the alternator statorand/or diode circuitis faulty. TEST 8. The 4TR voltage regulatoris checkedat normal operating temperatureson closedcircuit conditions usinga well-charged battery. (Run-cold engineat chargingspeedfor at leasr 8 mlnutes). (a) With ammeterin the main output cable,connecta voltmeteracrossthe batterytcrminals.SeeFig. 74. (b) Switch on side lamps, start and run engine at approx.3,000rev/min. (c) Ensure that the voltagc regulatoris regulating. (The ammeter must inlicat-e less than iOe ana shouldnot increasewith speed). (d) Vottmeterreadingshouldbe betweenthe limits: r 0/rr Ac STARTERSOLENOID Page34 Alternators VoltageRegulator Setting(Volts) l2V systems 24V systems t 3 . 9- 1 4 . 4 27-9-28.3 Note: l. A low readingindicatesa faulty 4TR unit. 2. If the readingis higherthan the limits or unstable, the test should be repeatedwith the voltmeter connectedacrossthe '*' and 'terminalsof the 4TR unit. 3. A high readingindicatesa faulty 4TR unit. A correct readingdenotesa high resistance in the sensingcircuit which must be located and remedied. 4. An unstablereadingis due either to a high resistancein the circuit (which must be checked)or a faulty4TR unit. 11AC F i g .7 3 C h e c k i n ga l r e r n a r om r a x i m u mo u r p u t CheckingVoltageRegulatorSetting (4TR) STARTER SOLENOID 12 VOLT BATTERY WELL CHARGED Fig.74 C h e c k i n gv o l c a g er e g u l a c o rs e t t i n g ( 4 T R ) -!tlC:ls - 7\ A L o o ; Fig.75 C h e c k i n g3 A W w a r n i n gl i g h cc o n t r o l TEST 9. Checking3AW Warning Light Control The 10AC and I IAC alternatorsystemsnormally incorporatea 3AW chargewarninglight control. but If the chargingsystemis operatingsatisfactorily' the warninglight doesnot functioncorrectly(eitherby 'on' or 'off'), it indicatesthat the 3AW or remaining the connectingwire is faulty. 'AL' terminalol' (a) ' Connecta voltmeterbetweenthe (Fig. 75a). the alternatorand earth. (b) Start and run tbe engineat approx.1,500_rev/m!g, The voltmeter should read between6-EV (l2V s y s t e m so)r l 4 - t 5 V ( 2 4 Vs y s t e m s lA . hirh voltage o r n o r e a d i n ga t t h e ' A L ' t e r m i n a il n d i c a t efsa u l t y rectifierdiode. ( c ) R e m o v et h e l e a d sl t o m t e r m i n a l s' E ' a n d ' W L ' o n t h e 3 4 W . a n d l i n k t h e m t o g e t h e r( F i g . 7 5 b ) . W h e r rt h e i g n i t i o ni s s w i t c h e d' o n ' . t h e w a r n i n g lamp shouldbe illuminated. N o t e : l . l f t h e b u l b n o w l i g h t s ,t h e 3 A W c o n t r o li s probablyfaulry. 2 . S h o u l d t h e w a r n i n g l i g h t r e m a i no u t . t h e bulb and circuitshouldbe checked. Page35 1 . 1 1 0 - 1 . 1 3 0DISCHARGED 1.230-1.250 TOZCHARGED 1.270-1.290 CHARGED Fig. 76 Hydrometer test 1s| 16117 l18l20ACR SYSTEMS TEST 1. Battery Test Using a hydrometer,check that the battery is at leastl0/, chargedand in good condition,seeFig.76. A battery fault can have an adverseeffect on the chargingsystem. For example,a sulphatedbattery will producc a low charge rate, whereasa battery with a shortedcell will producea high chargerate. TFST 2. Drive Belt Tension Allow l3-19 mm (0.5"-0.75")play when moderate fingerpressureis appliedto the longestrun of the belt, seeFig. 77. The alternatorwill not chargethe batteryif the drive belt is too slack. On the other hand,an excessively tight belt may damagcthe bearings. If thc belt is worn or oily, it shouldbe replacedwith a prcmium grade type. TEST 4. CableContinuity (a) Removeall the connectionsfrom the alternator terminals. (b) Switchon the ignition. TEST 3. Connections E n s u r et h a t a l l l e a d sa r ei n o o s i t i o n . belt tension Starter '., \l Fig.78 Cablecontinuicy Page36 (c) Connectthe voltmeterbetweena good earth and leadsin turn. Fig. 78. each of the disconnected The voltmeter should indicate battery voltage. open-circuitleads Note: l. A zero readingindicates 'IND' lead). (or faultYbulb if 2. Where the additionalearth terminalis used on the alternator,the voltmeterreadinglor that connectionwill be zero. 4. On replacingthe connections,failure of the warning light indicatesa faulty alternator field ciriuiior regulator' If the warninglight is illuminated,Proceedto Test 5. CheckingAlternator Maximum Output 5. TEST The alternatorshouldbe run for a fcw minutesto en' sure that the tests are carried out at the normal operatingtemPerature.Then, stop the engine. (d) Disconnectthe batteryearth cable. (b) Conne"t an ammeterbetweenthe startersolenoid ' terminal and the alternator main output cable' . Fie.79. at the alternatorand the the connections (c) Re-move moulded cover. Then re-make the connections. 'F' and Use a iumper lead to short togetherthe ' - ' c o n n e i t i o no s [ t h e v o l t a g er e g u l a t o ur n i t . 8TR - Greenlea<iand black iead(i.e. earth). 8TRD - Greenlead and earth. llTR/l4TR - Regulatorframe and earth' (d) Re-connectthe battery earth cable. (e) Switch.onthe ignition (or auxiliary switchfor diesel vehicles)and Checkthat the warning light comes ; Fig.79 C h e c k i n ga l t e r n a t o r m a x i m u m o u t P u t SOLENOID (f) Start the engineand slowly increasespeed. At approx. 3,000enginerev/min, the a.mmeterrea-ding si6uld equal thi maximum rated output of the al,ternator. Alternator Model I5ACR I5ACR ITACR ITACR (De-rated) I8ACR 2OACR AmmeterReading Fig. 80 SOLENOID 28A 34A 36A 25A 43A 66A Note: lf the ammeterreadingis low, the alternatoris at fault. TEST 6. CheckingVoltageDrop in ChargingCircuit in the Use a voltmeterlo checkfor high resistance chargingcircuit,seeFig. 80. (a) eonnecta voltmeterbetweenthe batteryinsulated terminaland the alternatormain output terminal' on (b) Switchon the vehiclelightingload (headlamps main beam). Start and run engine at approx. 3,000rev/min. The voltmeterreadingshould not exceed0'5V. (c) Transferthe voltmeterconnectionsto the battery earth terminal and the alternator body. (d) Start and run the engineas in,-(b).The voltm€ter readingshouldnot exceed0'25V. Note: If tlie readingsare higher,then there is a high resistancein the circuit which must be located and rectified. TEST 7. CheckingYoltageRegulatorSefting settlng'lt ls Before checkingthe voltageregulator_ essentialthat a bittery in a well-chargedconditionis fitted to the vehicle. (a) Disconnectthe battery earth cable. (b) Connect an ammeterbetweenthe starter solenoid ' terminal and the alternator main output cable. Connecta voltmeteracrossthe batteryterminals. F i g .8 1 . C h e c k i n gv o l t a g ed r o p i n c h a r g i n gc i r c u i t v Fig.81 C h e c k i n gv o l t a g er e g u l a t o r s e t t i n t (c) Re-connect the battery earth cable. (d) Start and run the engine at aPProx. 3,000 rev/min until the ammeter reading is less than l0 amperes' The voltineter reading should be within the limits 13.6-14.4V. If the reading is unstableor outsidethe.specified timits, the voltige regulatoris faulty and shouldbe replaced. first alterna.tors, Note: When checkingbattery-sensed check for hilh resistancein sensinglead' Connect known good lead between battery 'i-ve' terminal and alternator terminal 'B-i-' and repeatTEST 7' Page37 LIGHTING INTRODUCTION In order to comply with legal requirements,the motor vehicle must be fitted with ceitain forms of lighting which musr be maintainedin working condition. Although the requirementsmay vary s l i g h t l yw i t h different types ol vehicles,in general.the present requirements are as follows: l. Headlamps(two minimum). 2. Side,'rearand numberplatelamps. 3. Directionindicatorlamps. 4. Stop lamps. Apart. from the legal aspect,efficient lighting will enablethe driver to "see and be seen",and a driver usingdeflective. or in-correctlyalignedlamps is not only a danger to himself but also to other road users. Ii must be rememberedthat lights and lamp alignmenr are part of the M.O.T. test on vehicles'requ-iring a certi6cate. Additionallampsmay be fittedto a vehicle.but they must c_omplywith the regulationsgoverning thosl particularlamps. -Fcr example,any addirionallampsfittedto the front of a vehiclewhere the mounringheight exceeds24" from the groundto the centreof the lari'psautomatically becomeheadlampsunlessthey ari used in conditions of fog or falling snow. As such, they musr comply with requirements applicableto headlamps. When.testing ligtrting circuits the "volt drop" prin. c.iplewill be used. This will involve checliingthe 'irupply voltage available" under load (at the baitery) then the voltageavailableat the actual iamp involvei. Where the differencein voltageexceedsthi peruritted limits the voltmeter will be connectedin parillel with both the supply and return sidesof the ciriuit to deter. mine where the fault exists. The exact procedure will be statedin this section. In the caseof directionindicatorcircuits.it will be necessary to use an ammeterin addition to the voltmeter,as the operationofthe "flasher"unit is deoendent on currentconsumption. BATTERY TAIL LAMPS SIOE LAMPS F i g .8 2 C h e c k i n gt h e s i d e a n dt a i I l i g h rc i r c u i t Page38 LIGHTING IGNITION SlYITCH + H swlTcH TO orPSwrTcH SIDE AND TAIL LIGHT CIRCUIT ALL TESTSWITH SIDE AND TAIL LTCHTS SWITCHED ON. Refer to Fig. 82 for voltmeterpositions. TEST l. Vohage st the Battery under Load Connectvoltmeter(Vl) acrossthe batterytefminals and notc the reading. TEST 2. Yoltageat bulb connections Connectthe voltmeteracrossthe bulb connectrons as (V2). Note the reading. The differencein reading (volt drop) should not exceedl0l of the systemvoltproceedto Test 3 age. If the volt drop is excessive. ( i n s u l a t e dl i n e ) . TEST 3. Voltagedrop on insulatedline Connect one side of voltmeterto lhe batterv ins u l a t e dt e r m i n a l a n d t h e o t h e r s i d e t o t h e b u l b i n s . u l a t ecdo n n e c t i o na s ( V 3 ) . Note the reading. TEST 4. Voltagedrop on earth line Connectone sideof the voltmeterto thebatteryearth t e r m i n a la n d t h e o t h e r s i d e t o t h e b u l b e a r t h c o n nectionas (V4). Note the reading. lf the total of the readingsfor Tests3 and 4 exceeds l0l of the systemvoltage,a high resistance exisrson either the insulatedor earth linesor possiblyboth. Bearingin mind that the total volt drop allowedis 10ft (approx. l.2V for a 12 volt systero).it is permisibleto haveall this drop on one line or the other or as a combinationof both lines. TEST 5. Bulb earth connection lf the volt drop figureon tlreearthsideis the higher, it is probably due to a bad connection betweenthe lamp body and earth. To check.connectthe voltmeter betweenthe bulb earthconnectionand a good vehicle earth(V5). Any readingindicatesvolt drop. TESTS 6,7, 8,9 and 10. Checkinginsulatedline To checkvolt drop on the insulatedline connectone voltmeterlead to the batteryinsulatedterminal and movethe other voltmeterconnectionas in (V6), (V7). ( V 8 ) .( V 9 ) a n d ( V l 0 ) u n t i l t h ef a u l t ys e c r i o ni s l o c a r e d . HEADLIGHTS, STOP LIGHT AND DIRECTION INDICATOR CIRCUlTS To checkthesecircuits.exactlythe sameprocedure is usedas describedfor the sideand tail circuit. (Refer t o F i g s .8 3 . 8 4 a n d 8 5 ) . l n t h ec a s eo f d i r e c t i o ni n d i c a t o ros n ea d d i t i o n atle s r is carriedout togerherwirh the volt drop tests. This involvesremovingthe two leadsfrom the 8FL f l a s h eur n i t o r t h e l e a d sm a r k e d ' B ' a n d ' L ' f r o m t h e F L 5 a n d c o n n e c t i na g n a m m e t e ri n s e r i e sw i t h t h e s e l e a d sa, s s h o w ni n F i g .8 5 . with the indicatorswitchin either rhe rieht- or lefthand position,the indicatorlampson onelide should light and the currentregistered on the ammetershould b e t h a t o f t h e f l a s h eu r nitrating. E . g .3 - 6a m p so r 4 . 3a m p so r 4 . 8 a m p s . S h o u l dt h e c u r r e n tc o n s u m p t i o n o t m a t c h u p t o that specified on the unit, then the rate of ffashwill be incorrect.This is causedby one of the following: l. The wrong flasherunit hasbeenfitted. 2. Bulbsof incorrectwattagehavebeenfitted. 3. One bulb is faulty lthis can be checkedvisualty). 4. A high resistance existsin the circuit. This should be locatedusingthe volt drop testprocedure. Note: Whentestingindicatorlampcircuitsdo nol make a directearthconnection to any of the indicator (i.e. bulb conracts). lamp insulatedconnections BATTERY SoLENOTO W LIGHI F i g . 8 3 C h e c k i n gt h e h e a d l a mcpi r c u i t Page39 STOPLAMPS IGNITION swtTcH F i g . 8 4 C h e c k i n gt h e s t o p l a m pc i r c u i r FLASHER UNIT C h e c k i n gr h e d i r e c t i o n i n d i c a t o r c i r c u i c Prge 40 HEADLAMP ALIGNHENT As previouslystated, the headlampscan only be fully eificientwhen correctlyaligned. T h e L u c a sB e a mT e s t e rM k . l l l , a ss h o w ni n F i g . 8 6 ' for the accurate is an instrumentdesignedspecifically checkingand alignmentof all typesof vehicleheadlamps. an alternativebut In the absenceof a beamtester, lessaccuratemethod of checkingthe alignmentis as follows; (seeFig. 87). Positionthe vehicleon a pieceof levelground25 ft. from the wall (or door) to be usedas a screen' (25 ft. is requiredin order to obtain a suitablebeampattern). The iehicle must, as far as possible,be at right-angles to the wall (or door). Crossesare marked on the wall correspondingto the samecentresas the headlamps(i.e. samedistance apart and from the ground). Thesemarks are then usedas a guide line for the correctalignment. Fig. 86 CentreLine Of Vehicle LucasBeam Tester Mk. lll AreaOf Concentrated Light Lloinht f)f LampCentres FromGround A- FrontOf VehicleToBe SquareWith Screen. B-VehicleToBe LoadedAnd StandingOn Level Ground' C-RecommendedDistanceFor Setting ls At Least 25ft' D-For EaseOf SettingOne HeadlampShouldBe Covered' F i g . 8 7 H e a d l a m pa l i g n m e n c( w i t h o u c b e a m c e s t e r ) Page4l WIPERMOTORS ) \:. /r (s INTRODUCTION WIPER TEST PROCEDURE The modernwiper motor is a permanentmagnettype incorporating two ceramic magnets housed in a cylindrical steelyoke. This type of arrangementproducesa highertorque output than a normal wire-wound field systemand consequentlywiper arms having increasedspring pressurecan be used, "Permanentmagnet" wipers are producedin either single- or two-speedform. The high spced requirementsareprovidedby a secondpcisitivebrush position to which tbe supplyis connectedwhen the higherspeed is required. A further featureof this unit is dynamicor regenerative brakingwhen the wiper switchis movedto the park position. The control for this operationis on the gearbox casting. Thesemotors are also availablein "self-switching" or "sel[-parking"versions. The "self-switching"unit will stop at the end of its normalwipingarc. The "sell-parking" motor, when switchedofi will reverseits rotatioo, operate an eccentriccoupling and extendits length of stroke to park beyondthe normal wiping arc (usuallyoff the screen). Testingof wiper switchingand circuitscould become an exceedingly complex procedure. We therefore recommenda quick but simple method of establishing whether the fault lies in the wiper motor itself or the switching. ihis involvesthe usebf a made-uptestplug. The plug is the common wiper plug (easilyobtainable), as used on all present-daypermanentmagnetmotors, connectedwith four leads,red, blue, yellow and white as shown in Fig. 88. Note: Plug connectionsI and 2 should be linked at rear of plug (blue lead). Removethe wiper motor plug on the vehicleand insert the test plug. By connectinga lZY supply with ammeterin series acrossthe various conrbinationsof the test plug leads as shown in the following tests, it will be possibleto determine: (a) That the motor is operatingcorrectly. (b) The current consumptionof the motor (2-4 amps). ALL TESTS WITH SCREEN WET. ARMATURE NORMAL SPEED 1 4 W ,1 5 W , 1 6 W W I P E R S + SUPPLY F i g . 8 8 W i p e r m o t o r c e s tp l u g Page42 F i g . 8 9 T e s t1 . 1 4 W , 1 5 W a n d 1 6 W w i p e r s Connectrons '-' Batt. B a t t .' - ' rEsrr. (Fie.8e) I | I | I fyp. ol motor | | Result | I I All types M o t o r r u n sa t Blue I I I normalsPeed | | | Donotdisconnectbattcrysupplyfronrplugwhilethcwiperbladesareintheparkedposition Red TEST 2. (Fie9 . 0) Yellow Blue 2-speedmotors only M o t o r r u n sa t high speed Red White Sel[-switch ing typesonly M o t o r s h o u l dr u n to parkposition then stop TEST4. (Fig.92) White Red i ng Self-park typesonly M o t o r s h o u l dr u n to extended park position thenstop TEST3. ( F i e9 . tl HIGH SPEED 1 4w , 1 5 w , 1 6 w W I P E R S + ARMATURE F i g . 9 0 T e s t2 . 1 4 W ,1 5 W a n d1 6 W w i p e r s P A R K P O S I T I O N& S T O P 14W & rsw WTPERS + 12V SUPPLY F i g . 9 1 T e s t3 . 1 4 W a n d 1 5 W w i p e r s Page43 ARMATURE P A R K P O S I T I O N& S T O P 16W WTPER F i g . 9 2 T e s r4 . 1 6 W w i p e r s If the motor fails to functionin any one or more of the previoustests,a laulty motor is indicated.lf, however, the motor is satisfactory,the fault lies in the switchor wiring on the vehicle. Should the current consumptionduring the tests exceed4 amps,removethe wiperarms and bladesand repeattest. lf current is still high this could indicate friction in the rack or link drive mechanism. excessive Disconnectthe drive from the motor and againcheck current consumption. A high current reading now indicatesa faultymotor. On the rack-typedriv? a pull Fig. 93 Page zl4 C h e c k i n gt h e w i p e r m o [ o r I r a n s m i s s i o n of 6 lbf. appliedto the crosshead with a springbalance shouldbe sufficientto move the crossheadwithin the outer casing,see Fig. 93. If not. the assemblymust be examinedfor faults. Note: lt should be remembered that whereexcessrve frictionexists,overloading will result.Replacing the motor will not solvethe problem. ln caseswhere removal of the arms and blades Iowersthe current consumptionthe fault is due to eithera contaminated screenor faulty arms or blades. NOTES r..*ii: