Detonation - Pings, Spark Knock

A mild to severe ping, usually worse under load or acceleration. Sounds like something is rattling or knocking in the engine.

POSSIBLE CAUSE

Ignition Timing Advanced
- Check Ignition Timing in "Adjustment
Procedures"

Spark Timing Not Retarding
- Test the Ignition System

Poor or Contaminated Fuel
- Recommend higher grade fuel