Page 196 - CTS - Mechanic Diesel - TP

MECHANIC DIESEL - CITS

EXERCISE 11.3: Trouble tracing in the ignition circuit and

components

Objectives

At the end of this exercise you shall be able to
• check continuity in ignition circuit
• check open circuits in ignition circuit
• check short circuits in ignition circuit
• check the spark plug for proper functioning
• check the ignition coil for proper voltage build up
• set ignition timing
• check a condenser for proper functioning
• set and adjust the ignition timing.

Requirements

Tools/Instruments
• digital multimeter - 1 No. • Ignition timing light - 1 No.
• continuity meter - 1 No. • Spark plug testing m/c - 1 No.
• ohm meter - 1 No. Materials
• DE spanner 6 to 32 - 1 Set
• electrical tester - 1 No. • Tray - as reqd.
• executive auto electrical toolkit - 1 Set • Cotton cloth - as reqd.
• pulley set universal for bearing • Kerosene - as reqd.
& bushes - 1 No. • petrol - as reqd.
• Spark plug feeler gauge - 1 No. • Engine Oil - as reqd.
• Spark plug spanner - 1 No. • Coolant - as reqd.
• Test lamp - 1 No.
Equipments/Machines • Spark ignition coil - 4 No.
• Multi cylinder four stroke Petrol • Spark spare plug - 1 Set
engine - 1 No. • Spare HT wire set - 1 No.
Procedure

1 Check the battery terminals and tighten them if found loose
2 Using a AVO meter (multimeter) in 12 volts range, connect the leads on both the +ve terminals of the battery
(1) and the ammeter (2) input lead to check continuity. Fig.1

3 Check the continuity between:
• Ammeter (2) and the ignition key (3).
• Ignition key (3) and ignition coil (4).
• Ignition coil (4), ignition point (5) and condenser (6)
• Ignition coil (4) and the distributor cap (7) motor.
• Distributor outer terminal (7) and each spark plug (8).

4 If there is any open circuit replace the defective leads. If any loose connections are found in the above circuit
tighten them.
5 Check the ignition coil by (Fig 2) connecting the DC voltmeter (1) in parallel with the primary circuit and switch
“ON” Note the reading in the voltmeter

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CITS : Automotive - Mechanic Diesel - Exercise 11.2