Originally Posted by
steveo
didn't look at your log, just a few thoughts
your analysis and logic sounds good. knock count followed by retard followed by the knock count increment stopping is usually real knock. if the knock counts are real, carbon buildup in the combustion chambers or poor fuel quality would be the first things to look at. another reason would be more aggressive timing than your particular engine or vehicle can handle (running a light truck tune in a bigass truck engine swap)
but keep in mind very subtle momentary false knock can behave the same way, just because it disappears after timing is retarded doesn't mean the timing retard caused it to dissapear (cause and effect)
a few hundred knock counts happening randomly is typical of false knock..
the conditions during which the knock counts occur is very important as well. is TPS% or MAP increasing during the knock events? if so, they are probably real. if you are cruising or in decreasing load when it occurs, i'd be doubting their authenticity.
keep in mind too, sometimes its not an internal engine problem. something as stupid as a loose exhaust pipe banging on your floor pan can resonate to the engine and cause knock counts (and in some cases the timing retard removes enough torque to relax the engine mounts and stop the banging, really throws you for a loop)
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