IGNITION SYSTEM SERVICE

1
IGNITION SYSTEM SERVICE
2
TESTING AND REPAIR

• Evaluate the symptoms
• Narrow down possibilities
• Pinpoint to a specific engine system
• Compression
• Fuel
• Ignition
• Perform basic tests first
• Visually inspect

3
PRELIMINARY TESTS

• Look for obvious problems
• Loose Connections
• Cracked components
• Deteriorated/Burned components
• Inspect other systems
• Do you have a dead cylinder?
• Perform manual cylinder balance test
• RPM will change if cylinder is good

4
SPARK INTENSITY TEST

• Usually used with a No Start
• Can be used to test component integrity
• Install spark tester and observe spark

5
SPARK TEST RESULTS

• Spark should be a good strong spark
• Wide
• Bright blue
• Snapping electric arc
• Is it weak at one spark plug or all?

6
SPARK PLUG SERVICE

• Bad spark plugs can cause many problems
• Misfiring
• Lack of Power
• Poor Fuel Economy
• Hard Starting

7
SPARK PLUG PROBLEMS

• Can become coated with ash, oil, and fuel
  additives
• Electrodes can burn and widen gap
• Electrodes can deteriorate with age or cylinder
  efficiency

8
SPARK PLUG REMOVAL

• Number wires to cylinders
• Grasp boot, not wire
• Blow debris from hole
• Do not mix up spark plugs
• Inspect Read spark plugs

9
SPARK PLUG SERVICE

• Clean spark plugs
• Gap spark plug to specifications
• Install Spark plugs

10
SECONDARY SERVICE

• Remove Spark Plug wire
• Test wire for high resistance
• Not over 10,000 ohms per foot
• Secondary insulation test
• Grounded Probe
• Spray water
• Look at wires at night
• Replacement of wires must be correctly done

11
DISTRIBUTOR CAP AND ROTOR

• Must visually inspect cap and rotor
• Can cause backfiring and misfire
• Carbon arcing can cause problems
• Cracks can cause problems

12
ELECTRONIC DISTRIBUTOR SERVICE

• PICK UP COIL PROBLEMS
• Can cause misfire, stalling, no-start, hesitation
• PICK UP COIL TESTING
• Use ohmmeter
• Must measure to specifications
• Wiggle and Tap test pick up coil
• AC analog voltmeter test
• Lab Scope

13
PICK UP COIL SERVICE

• Follow procedures to replace
• Some ignition systems pick up coil air gaps are
  adjustable

14
IGNITION TIMING

• Initial (or base) timing
• Must follow procedures exactly! Check Specs
• Must set during tune up or if distributor has
  been removed
• Must make sure advances not working during
  adjustment!

15
IGNITION TIMING ADJUSTMENT

• Disable ignition advances
• Hook up timing light
• Adjusting timing causes pickup coil and
  electronic control unit to fire the ignition coil
  sooner or later.
• Turning distributor housing against shaft
  rotation advances timing
• Turning distributor housing with shaft rotation
  retards timing

16
IGNITION TIMING PROBLEMS

• TIMING MUST BE EXACT! VERY IMPORTANT!
• Too far advanced will cause Pinging, engine
  damage
• Too far retarded will cause low power, poor
  mileage, engine damage

17
MEASURING IGNITION TIMING

• Strobe type timing light
• Magnetic timing probe
• Usually connect light to number one cylinder
• MUST DISABLE ADVANCE
• Vacuum advance
• Mechanical (centrifugal) advance timing
• Computerized timing advances
• Align timing marks to specifications

18
CHANGING IGNITION TIMING

• Loosen distributor hold down bolt
• Use distributor wrench if available
• Engine rpm low
• No advance operation
• Align marks
• Tighten hold down bolt
• Double check timing