Question about Knock Sensors and Spark Grounding...

[dc_justin]

I'm just throwing this idea out there to see if it may have any traction.
For quite a long bit of time, I've been seeing random KR spikes up in the 7s-8* while in boost. I've got plenty of fueling (Wideband isn't hooked up right now, but Narrowbands are in the 930s range). Normally I've never been able to actually hear the knock, but lately I've been driving by a wall on the highway with the window down and I've been able to pick up an audible *tick* sound. No resonant *ping* noise, just a single *tick*, much like you'd hear from a motor cooling down after you stop driving or what you might hear from a spark plug wire arcing. Since this is happening in boost, I'm incline to think that if it isn't real knock, then it could be the spark grounding out somewhere as the cylinder pressures are rather high and making it tough to make the jump.

Is this possible that a grounding spark plug wire could trigger the knock sensors??

3000 miles of driving with daily KR spikes, pulled the plugs and they look like I just pulled them out of the box, brand new...

[joecar]

I'm incline to think that if it isn't real knock, then it could be the spark grounding out somewhere as the cylinder pressures are rather high and making it tough to make the jump.Sounds plausible, tick sound; plug wire insulation has been known to dielectrically break down under load.


Is this possible that a grounding spark plug wire could trigger the knock sensors??Don't know.


3000 miles of driving with daily KR spikes, pulled the plugs and they look like I just pulled them out of the box, brand new... Possiblity, if you haven't already looked at this:
in your log chart, look at DYNAIR right where the KR spike occurs, if DYNAIR rises sharply, then the burst knock retard mechanism might be kicking in, and this will just look like a single KR pulse (if the KR looks like sawtooth shaped, then it may be real).

[dc_justin]

Sounds plausible, tick sound.

Don't know.

Possiblity, if you haven't already looked at this:
in your log chart, look at DYNAIR right where the KR spike occurs, if DYNAIR rises sharply, then the burst knock retard mechanism might be kicking in, and this will just look like a single KR spike (if the KR look like sawtooth shaped, then it may be real).

Yeah, I don't think it is Burst Knock, as the big spikes typically happen after I've been in boost steadily for a few seconds and my air mass per cylinder is not changing dramatically.
I have the Scan tool set up to play an alarm when I spike larger than 3*, so once that happens I typically back off the throttle so I'll never see the sawtooth activity.

[oztracktuning]

The alarm is a good idea - i just found out how to do this for my car