Spark Knock noise?

TedB370z

I highlighted the times around when it happens....

Teds370zdatalog.zip

I had it log everything that the AutoGaugeX app could... (I have a Win8 phone...)

***This was from a parking lot, down a slight grade to a highway, regular driving on the highway, red light (when I pulled away is when the issue occurred) regular driving, then some spirited acceleration, then back onto the slight up grade, parking lot, then stopped and when I pulled in slowly it did it again, but very lightly.***

SouthArk370Z

It looks like the throttle plate isn't opening. "%Throttle" = 2 from 11:51:30 to 11:52:12. Ie, the ECU doesn't seem to be telling the engine to go faster. But, IIRC, the Throttle Position Sensor (TPS) that is reported via OBD has been massaged to account for VVEL. I'd try logging gas pedal position params (more than one) and see if it is sending the right signals.

And spark advance drops below zero. That sounds like anti-knock kicking in, which could cause the above. IAT and water temp aren't high enough to cause that much spark retard.

My wild guess is that it an anti-knock problem - the knock sensor(s) are too sensitive, something is rattling around and triggering the knock sensor, or you're actually getting knock for some reason.

But I'm definitely not an expert at this stuff, so take what I say with a grain of salt.

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