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 Spec’s • 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