Faulty Secondary Patterns

Bad Secondary Pattern (Parade):

With the engine running at idle RPM, ignition voltage line height should be between (6-16 kV), and the maximum difference between cylinders should not vary by more than (3 kV). If the pattern indicates higher than normal required voltages at all ignition lines, a problem may be present with:

^ Faulty ignition coil wire or connections
^ Wide spark plug gap at all cylinders (possibly due to high milage or improper adjustment)
^ Faulty distributor cap or rotor

Bad Secondary Pattern (Parade):

Individual ignition voltage line heights that are abnormally high accompanied by short burn times may indicate: (Can occur at any engine RPM, with or without load)

^ Wide gap at the spark plug electrode
^ Faulty distributor cap
^ Fuel/air mixture too lean

Bad Secondary Pattern (Parade):

Ignition voltage line heights that are abnormally low accompanied by longer burn times may indicate: (Can occur at any engine RPM, with or without load)

^ Spark plug gap too small or partially fouled plug
^ Loss of compression
^ Fuel/air mixture too rich

Bad Secondary Pattern (Parade):

Burn voltages greater than 1.5 kV accompanied by sloping burn voltage lines may indicate: (Can occur at any engine RPM, with or without load)

^ Carbon or oil fouled spark plugs
^ Excessive resistance at secondary components

Bad Secondary Pattern (Single Display):

Ignition voltage line height that is less than 5 kV at engine cranking speed (Engine not running) may indicate:

^ Faulty ignition coil
^ Incorrect circuit 15 voltage
^ Incorrect circuit 1 voltage

Bad Secondary Pattern (Single Display):

No decay process at cranking speed (Engine not running) may indicate:

^ Faulty ignition coil

Bad Secondary Pattern (Single Display):

Missing or to few decay oscillations at any engine speed, with or without load may indicate:

^ Faulty ignition coil

Bad Secondary Pattern (Parade):

Ignition voltage line height at a single cylinder is less than 6 kV at cranking speed (Engine not running) indicates:

^ Faulty ignition coil

Bad Secondary Pattern (Parade):

Decay process too high on a single cylinder when accelerating engine to approx. 3000 RPM repeatedly or while operating the engine under a load on a dynamometer.

^ Air/fuel mixture is too lean at one cylinder

NOTE: Malfunction may occur intermittently

Bad Secondary Pattern (Parade):

Decay process too high on all cylinders when accelerating engine to approx. 3000 RPM repeatedly or while operating the engine under a load on a dynamometer.

^ Air/fuel mixture is too lean on all cylinders