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Ignition System Diagnostics. Reading A Scope Pattern. The Scope. FIRING ORDER. FIRING ORDER. Some older scopes read # 1 cylinder to the far right. Secondary Patterns. Most often used Are read in Parade or Raster Display actual voltage needed to fire each spark plug Duration of each spark
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Ignition System Diagnostics Reading A Scope Pattern
FIRING ORDER • Some older scopes read # 1 cylinder to the far right
Secondary Patterns • Most often used • Are read in Parade or Raster • Display actual voltage needed to fire each spark plug • Duration of each spark • Coil condition • Secondary circuit resistance
NORMAL PATTERNS • FIRING LINES HAVE 7 THOUSAND TO 10 THOUSAND VOLT RANGE • NO MORE THAN 3,000 VOLT DIFFERENCE BETWEEN CYLINDERS • KV IS AN ABBREVIATION FOR THOUSAND VOLTS
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Can Be Caused By • Spark Plugs • Coil • Cap/Rotor • Fuel Air Mixture • Timing • Compression