1.Evaluate the
symptoms
–Narrow down possibilities
2.Pinpoint to a
specific engine system
- Compression
- Fuel
- Ignition
3.Perform basic
tests first
–Visually inspect
PRELIMINARY TESTS
Look for obvious
problems
- Loose Connections
- Cracked components
- Deteriorated/Burned components
- Inspect other systems
lDo you have a
“dead cylinder”?
- Perform manual cylinder balance test
- RPM will change if cylinder is good
SPARK INTENSITY TEST
- Usually used with a No Start
- Can be used to test component integrity
- Install spark tester and observe spark
- Spark should be a good strong spark
- Wide
- Bright blue
- Snapping electric arc
- Is it weak at one spark plug or all?
spark plugs
can cause many problems
- Misfiring
- Lack of Power
- Poor Fuel Economy
- Hard Starting
- Can become coated with ash, oil, and fuel additives
- Electrodes can burn and widen gap
- Electrodes can deteriorate with age or cylinder efficiency
- Number wires to cylinders
- Grasp boot, not wire
- Blow debris from hole
- Do not mix up spark plugs
- Inspect “Read” spark plugs
- Clean spark plugs
- Gap spark plug to specifications
- Install Spark plugs
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
DISTRIBUTOR CAP AND ROTOR
- Must visually inspect cap and rotor
- Can cause backfiring and misfire
- Carbon arcing can cause problems
- Cracks can cause problems
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
PICK UP COIL SERVICE
Follow
procedures to replace
Some ignition
systems pick up coil air gaps are adjustable
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