VI ELECTIIICAL 3 41 IGIIITICII SYSTEM Pm ni Disirihulor S rvio 4 3 50 lgnilion Sysi m Diagnosis 3 41 Cunnral 3 41 llparallon 4 3 M Ignition Sysiom Conponmls 3 II Tro bI sliaoIInn Procnilnros 4 347 GENERAL tent spark knock which is a result of climatic factors such as temperature air density and humidity The ignition spark must occur at the correct time Underhood temperatures are increased by the and with sufficient intensity to ignite the compressed use of air conditioning especially during long fuel air mixture All components of the ignition sys periods of idling overloading trailer pulling op tem must function properly for satisfactory and erating in too high a gear and the installation economical operation of accessories that restrict airflow The coil must be able to transform the low primary Air density increases as barvmetriv Preeeure voltage to a secondary voltage high enough to supply riees arid as temperature drePe A eieiiee miitture sufficient spark for all conditions of load and speed of air and fuel drawn inte the cylinder has the The ignition distributor must perform two functions Same effect as raising the cerripreeeiuh ratio It must distribute the high tension secondary voltage Which ih turn increases the Pessibiiity of spark to the spark plugs in proper sequence It must also k 0k give the electronic control unit a signal to operate the Low humidity aisv iricreaeee the teridericY tv coil primary so the coil can fire the spark at just the spark kn ck High humidity decreeeee spark right instant for the engine to develop full power imcck At high speeds the spark must occur at the plug earlier in the ci 1pression stroke in order to give the mm mum Mgimg Km fuel air mixture ample time to ignite burn and apply is power rr the pim as it starts dm 0 the power Fri R A e me c d stroke Spark timing must vary in relation to changes t p mlle Oll lllllgallell lll ls The iqlllled in engine speed This is accomplished by the Octane mlmg Valle wltll each mode year centrifugal advance mechanism of the distributor Yelllclel Fuels of lllllval nt leSealch Owing ral During part throttle operation or cruising speed lllg ml 1y lmly lll lillelll lmoclllllg chalacterlstlui lll the fuel mixture is drawn into the cylinder through a aglvell ellgllla lt may be necessary tu reduce lm resiricted opening ar the carburetor and is less amt al t F g i than 2 l g fm The less dense mixture will burn slower and additional ii f t S l select all illmillilw Bwrce l advance is necessary for maximum economy This ad ual Ti h ld b ditional advance is furnished by the vacuum advance lgllllmll llllllgDlglllll ll hlmlllg S iii unit and operates in relation to throttle position and k l ll lle Sure ll ls Sel Wlllllll llpellllilcllllolli engine load The vacuum advance unit is controlled by NOTE The white mimi mark 0 HW timmy www carburetor ports v q m The Q f z i edvevce scale represents the Spa mtr spark worry in idk will dadvance engine timing with increases in engine Speed m tTDg T0 Dead gmtm spee Combustion Chamber Deposits An excessive IGNITNN SYSTEM mnmosis buildup of deposits in the combustion chamber may be caused by not using recommended fuels To determine an ignition system fault other than allll llllll lllalltB pllolollgell ellgllle lllllllgf ol coll snark knock refer tn ignition System Diagnnsis tinuous low speed operation The occasional use Guide of Carburetor and Combustion Area Cleaner Part Number 8992352 or its equivalent Group 15 410 or operating the car at turnpike speeds Engim Spgrk Knock FIM will reduce these deposits Distributor Advance Mechanism The Spark knock in some engines can be attributed to a centrifugal and vacuum advance units should be number of causes The most common is the intermit checked to be sure they are operating freely