Excessive cylinder wear Rebore or replace
block
Excessive valve guide Worn or loose bearing
clearance
Gap Bridged Deposits in combustion Clean combustion
chamber becoming fused chamber of deposits
to electrode
Blistered Engine overheating Check cooling system
Electrode
Wrong type of fuel Replace with correct
fuel
Loose spark plugs Retighten spark plugs
Over-advanced ignition Reset ignition timing
timing see ENGINE PERFORMANCE
Pre-Ignition or Incorrect type of fuel Replace with correct
Melted Electrodes fuel
Incorrect ignition timing Reset ignition timing
see ENGINE PERFORMANCE
Burned valves Replace valves
Engine Overheating Check cooling system
Wrong type of spark plug, Replace with correct
too hot spark plug, see
ENGINE PERFORMANCE
Chipped Severe detonation Check for over-
Insulators advanced timing or
combustion
Improper gapping Re-gap spark plugs
procedure
Rust Colored Additives in unleaded Try different fuel
Deposits fuel brand
Water In Combus- Blown head gasket or Repair or replace
tion Chamber cracked head head or head gasket
NOTE: Before diagnosing an electronic ignition system, ensure that
all wiring is connected properly between distributor, wiring
connector and spark plugs. Ignition problem will show up
either as: Engine Will Not Start or Engine Runs Rough.
BASIC ELECTRONIC IGNITION TROUBLE SHOOTING CHARTS
CONDITION POSSIBLE CAUSE CORRECTION
Engine Won’t Open circuit between Repair circuit
Start distributor and bulkhead
connector
Open circuit between Repair circuit
bulkhead connector and