Backfire

SYMPTOM DESCRIPTION
This condition occurs when; fuel ignites in the intake or exhaust system, making a loud popping noise.


POSSIBLE CAUSE ACTION


Voltage Output - Check for proper secondary output voltage with spark tester.


Spark plugs - Check for wet plugs, cracks, wear, improper gap, burned electrodes or heavy deposits.


Ignition Timing - Check distributor indexing.


NOTE: Check for crossfire between spark plugs (distributor cap, secondary wires, and proper routing of secondary wires).