Quote:
Originally Posted by simsalabim
I also run in Arizona.
Good food for thought here and I thank all. As far as the possibility of simply lugging the engine, would that create the dieseling noise I described (it sounds like scattershot pinging)? It does not seem to happen when I hard accelerate from say 3,000 rpm....
Also, by adding the Octane booster and/or dialing back the advance, which possibility will be tested for, pre-ignition or detonation?
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I have to agree with ClickClickBoom and say what you are likely experiencing is
detonation rather than pre-ignition. The difference between the two can be described as one is "too fast" (detonation) and the other is "too soon" (pre ignition).
Fuel is supposed to begin a burn (not explode) from a moment before the piston reaches the top of its stroke until the piston reaches its top, where the hot, expanding gas forces it back down. Detonation happens when the fuel mixture detonates or explodes (burns too fast) and expells its full energy on a piston that is moving upward towards it, causing a "bang" from its impact on the moving piston and its assembly. This is caused, as has been posted, by too hot of conditions within the cylinder (from a too lean a mixture), improper timing, or too low of octane. Adding octane booster or dialing back the timing can reduce the chances of detonation as can a fuel mix enrichment.