[Fanuc5]

A spark knock (or pining) is caused when the fuel going in to the cylinder is pre ignited. The cylinder isn’t all the way up in it’s compression stroke, when the explosion happens it tries to force the cylinder down but it cant go down until it has reached top dead center. This causes the ping.

What causes this? A hot cylinder chamber.

What can prevent this? Proper cooling of the engine.


I would check you cooling system and maybe have your radiator flushed, and change out you thermostat to a lower temp.

A higher Octane fuel lowers the temperature at which the fuel will auto ignite.


I hope this helps…