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Auto Electrical Works Paper 2, May/June 2014  
Questions: 1 2 3 4   Main
General Comments

Question 3


Question 3
(a)        State three faults that could cause the ignition warning light not to show when the ignition is in the ON position.
(b)        State three effects of a very large dwell angle.
            (c)        State three factors that affect the ignition timing of a motor vehicle.

The expected answers were:
             (a)     Any three faults
                      Burnt or loose bulb
                      Flat battery
                      Short circuit in ignition system
                      Open circuit
            (b)   Too large dwell angle will result in
                   (i) over saturation of the coil winding at low speed;                                          
                  (ii) overloading of condenser;                                                                             
                 (iii) burning of the points if the contact breaker;
                 (iv) weaker spark;
                 (v)  hard starting;
                 (vi) loss of power.                                                    
            (c)   Any three factors
                   Engine speed
                   Intake air volume
                   Shape of the combustion chamber
                   Inside temperature of the chamber
                   Compression ratio                                                                           
            The question was on Ignition System. It was unpopular with the candidates in spite of the   
            inadequacy in Question 3(a). The candidates’ performance was reported to be average.




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