Hope that this will help the neophytes in the course of Automotive Servicing NC II Focusing in Servicing Ignition System

1. IGNITION SYSTEM SERVICE
PREPARED BY: RUEL L. MONTEFOLKA

2. OBJECTIVES
• Identify common ignition system
parts with problems;
• Check and diagnose ignition
system parts;
• Perform servicing ignition
systems appropriately.

3. IGNITION SYSTEM SERVICE AND REPAIRS
The purpose of the ignition system is to ignite, or
fire, the spark plugs in order to generate power to run
the engine. To do so, the battery sends current to the
ignition coil. Then that high voltage goes on to the
spark plugs — either through a distributor, if you have
an older vehicle, or directly to the spark plugs, if you
have a newer one.
As an Automotive Technician it is important to have
a periodic maintenance check up for the ignition
system and parts.

4. BATTERY
One of the Major parts of the
Ignition System that sometimes
neglected in terms of checking
and servicing.
Check for battery connectors
and loose ground wires or any
wires connected to the battery
terminal in connection to the
electrical components…
Fluctuating current flow will
damage the sensitive electric
circuits. Make sure to include
and conduct a periodic checking
in the battery… 

5. IGNITION SWITCH CHECKING
The ignition switch is the master switch
that provides power for the vehicle's
electrical accessories, computer, fuel and
ignition systems. It also routes current from
the battery to the starter to crank the engine.
1. Check the Status of the Switch if the light
indicators in the panel/dash board
addresses the correct position of the KEY.
2. Problems Starting and Running Your
Vehicle. (No response in starting)
3. Overheating Switch ( This may cause for
grounded circuits)

6. BALLAST RESISTOR CHECKING
A device that protects the ignition
coil… it the one that prevents the
coil from overheating or
damaging due to the high surge
during starting.
Check for the continuity of
current flow through the coil and
its resistance enough to protect
the coil from high surge current
supply during starting. You can
use multimeter/tester for the
resistance and continuity.

7. To test the ignition coil connect the
ohmmeter's two test leads to the coils primary
terminals (+ and -). Most coils should read
between 0.4 and 2 ohms. Zero resistance would
indicate a shorted coil while a high resistance
reading would indicate an open coil.
Secondary resistance is measured between
the positive (+) terminal and high voltage output
terminal. Newer coils with segmented core
construction typically read 6,000 to 8,000 ohms,
while others can may read as high as 15,000
ohms.
On coils that are not a can style, the primary
terminals may be located in a connector or even
under the coil. Refer to the vehicle
manufacturer's service information for the
terminal locations and ignition coil test
procedures.
IGNITION COIL CHECKING
WARNING!!!
Never pull off a plug wire or the
coil's high voltage output wire to
test for a spark. Besides risking a
severe shock, an open plug wire
or coil wire will increase the
voltage demands on the coil to
the point where it may damage
the coil. The only safe way to
test for spark is to use a spark
plug tester tool.

8. CONTACT POINTS/CONDENSER
CHECKING
Refer to Info Sheet No.
2.5.1
Check the burning around
the breaker points. If no
burning or arcing the
condenser is literally in good
condition. However, if it is
opposite you have to replace
the condenser for safety
purposes…
Current passing through
the contacts burns away one
of them and deposits a peak
of metal on the other.

9. DISTRIBUTOR IGNITION CHECKING/SERVICES
1. DISTRIBUTOR IGNITION SYSTEMS
-Unique maintenance requirements
2. DISTRIBUTOR CAP AND ROTOR
SERVICE
-Distributor is cracked: carbon trail often
forms
-Excessive resistance in secondary
system: creates a hole at the tip of the
rotor
-Distributor cap has an aligning feature

10. SPARK PLUG CABLE CHECKING
1. REMOVING SPARK PLUG CABLES.
- Must be a careful operation application.
2. DETERMINE INTERNAL STRUCTURE OF A
CABLE IS SOUND.
- Check continuity and resistance with an
ohmmeter
3. CHECK CABLE ENDS FOR POSSIBLE
DEFECTS.
- Terminal is crimped tightly to the cable
4. SPARK PLUG CABLES BOOT
- Installed in the holes around the distributor cap.
CHECK IF THE CABLES ARE STILL GOOD OR
DURABLE ENOUGH.

11. SPARK PLUG SERVICE
-Use correct replacement plugs
-Use the correct spark plug heat
range
-Check the size of the threads
-Check to see if the old spark plug
used a gasket
-Check the reach or thread length
-Tapered seat plugs can be
difficult to remove
IMPORTANT POINTS!!!

12. 1. TEMPERATURE OF SPARK PLUG
-Relates directly to combustion chamber
temperature
2. CONDITION OF USED SPARK PLUGS
a. Indicates condition of engine and fuel
system
b. Spark plug wear
-Some use double platinum plugs
-Worn rounded electrode more surface
area to be charged
c. Fouled plugs
-Oil and ash deposits
SPARK PLUG DIAGNOSIS

13. SPARK PLUG DIAGNOSIS (CONT’D.)
1. Checking and adjusting the spark plug gap
2. Gap is set at the manufacturers standard specification.
3. Always double-check before installation.

14. PLEASE CLICK THE PICTURE TO WATCH A
VIDEO!!!

15. REFERENCES
• http://what-when-how.com/auto-repair/the-ignition-system-auto-
repair/
• https://www.howacarworks.com/ignition-system/fitting-and-
adjusting-contact-breaker-points
• Ignition System Overview
by Mark Davidson (http://www.auto-repair-
help.com/automotive_maintenance/ignition_system.php)
• https://www.google.com.ph/search?
q=distributor+assembly&dcr=0&source=lnms&tbm=isch&sa=X
&ved=0ahUKEwj5_4qs1YbYAhUBlpQKHQaNDWUQ_AUICigB
&biw=1366&bih=700