Ya could be. I would think a bad knock sensor or timing issue would cause a detonation or pinning sound?
Do you think a bad knock sensor would cause a knock at 3000rpm+ or under load?
It does't seem to knock unless under load. I know these things have knock sensor problems.. what sort of sound would a faulty knock sensor make?
The KS can't CAUSE knock, but, it is supposed to adjust the timing if there is one.
IE: You hear/feel a knock, not the sensor. The sensor is ALSO supposed to hear it (Feel it), and then retard the timing to help stop it.
So, it (KS) might not be working, but, it would be a symptom not a cause.
Knock, or ping if less severe, is simply the timing being a bit fast, so the charge goes off/gases are expanding to push the piston back down again... while the piston is still coming up to it.
So, if you are pushing a kid on a swing, you wait for the swing to crest, and, to JUST start back out again away from you as you add more push to send the kid swinging away from you again.
If you push the swing when its still coming towards you, the kid gets knocked off (Knock), or, jarred (ping).
The way its supposed to work, is that the timing is set to explode the gasoline, which then undergoes a flame kernel propagation leading to combustion and a fast expanding gas that drives the piston back through the cylinder....providing your power stroke.
If the charge is set off too early, the swing is still inbound when the gas hits it...and WHAM...you have knock.
If it hits less early, but still early, say before the MOMENTUM is allowing the swing to smoothly accelerate (The swing is crested, but not on the way down enough to not topple the tike off backwards on your push...)...you have ping.
And so forth.
So, how fast the gasoline burns makes a difference.
Premium burns SLOWER than regular (Higher octane rating = slower burn = slower flame kernel propagation, etc...).
So, if your timing is set for Premium (SC use premium), then, its going to be advanced enough to give time for the "slow" gas to do its thing.
If you use regular, it doesn't NEED that extra time, and, you can get knock or ping, etc...because the timing is too advanced.
The barometric pressure/altitude impact timing, in thinner air for example, the propagation speed is affected. For example, in Boulder Co, "regular" is lower octane than in say NJ or Fl, because you want LOWER octane up in the mountains, not higher...for the same timing curves.
The lower octane burns faster, compensating for the thinner air's slower propagation speed.
If you fill your SC tank up in the mountains (Where the Premium is also lower octane then Premium down at sea level), and then drive down to the plains of Death Valley, you can get knock even WITH Premium for example.
So, having an SC and using Premium works, using less than Premium is going to be a potential issue...except the knock sensor (KS) is supposed to retard the timing if it senses your engine is knocking the kid off the swing...
...So, both problems go together, but, neither causes the other.
As engines age, the compression can change, etc, and that can also change the effective timing that works...and so forth.
So, do any of the above sound like they might be involved?
>
PS - I'm a bit dyslexic, and 50% of the time, I type the opposite of what I meant to - but I put the swing analogy in there to act as a "control" for what's going on, in case I say something backwards.