Brucelinc said:
I may be mistaken but that makes zero sense to me from a tuning perspective. Usually there is a commanded timing formulated by a table of other sensor values (throttle position, load, IAT, ...). A car targets this timing as max/ideal for that situation and would pull timing from there if it detects knock. Its entirely possible this car does something crazy but I would have a better time believing they screwed something up in a formula.
Generally knock condition can be logged/displayed in 2 very different ways.
1: A number going from zero (no knock) to a positive number increasing with the frequency of the knock. This shows the actual knocks counts per time increment.
2: A number going from zero to positive or zero to negative (but never going through zero) showing how much timing is being pulled because of knock. This shows what the ecm is doing BECAUSE of knock but not the actual knock.
I really can't imagine an ecm just piling on the timing until it knocks. Increasing the target timing advance is something that's done when tuning to increase performance.
I also can't imagine how this read-out would flow from say -15 to 0 to +15. The engine starts at -15 adding all the timing it can but knock is detected so it instantly jumps to a positive number that keeps increasing the more knock there is? The engine starts at 0 and keeps going negative until knock is detected and jumps back to an increasing positive number?
The only way I can see this functioning is if its 2 gauges being displayed at the same time, timing advance and knock retard. But if that's the case their explanation of the positive and negative values should be backwards. You would really have to log / watch this gauge at the same time as the timing gauge while at full throttle to see whats going on. You would see actual timing advancing to targeted timing until it detects knock and removes some timing. At that time you'd have to see what this gauge is doing.
...or I just need to goto bed :baby:
