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-   -   Knocking without knock correction and knock correction without knocking (https://www.ft86club.com/forums/showthread.php?t=119520)

SorryTires 06-15-2017 11:18 PM

Knocking without knock correction and knock correction without knocking
 
So I've been getting quite a bit of low rpm/load knock like 20+ knock occurrences in a five minute drive. Almost all below 3000rpm and below 0.4g/rev load. Very few of these knock occurrences cause any knock correction and AM is pinned at 1 the whole time does that just means they are small knocks? is it normal to have so much knock but not have any knock correction?

Also sometimes knock correction happens without a knock signal. Is it normal to have knock correction happen when its not immediately preceded by a knock signal? or is it an error in the log?

Wayno 06-15-2017 11:44 PM

1 Attachment(s)
Opening up the rom and looking at the data will give you an inidcation of the logic.

SorryTires 06-16-2017 01:09 PM

That explains why there is usually no knock correction but I still don't get why there would be knock correction when it doesn't detect knock

Kodename47 06-16-2017 05:06 PM

What are you using to log, I'm assuming EcuTek? Don't forget that unless the knocking signal is the exact moment the logging polls that parameter it won't show. Also, not all instances that could trigger the knock sensor will retard timing. That and @Wayno's post answers the question.

SorryTires 06-16-2017 05:32 PM

Quote:

Originally Posted by Kodename47 (Post 2929972)
What are you using to log, I'm assuming EcuTek? Don't forget that unless the knocking signal is the exact moment the logging polls that parameter it won't show. Also, not all instances that could trigger the knock sensor will retard timing. That and @Wayno's post answers the question.

Yes I'm using ecutek. So there's potentially a bunch of knock that isn't shown as a knock signal because it happens between the log points? That significantly reduces the usefulness of logging knock signal

Kodename47 06-16-2017 06:57 PM

Quote:

Originally Posted by SorryTires (Post 2929991)
Yes I'm using ecutek. So there's potentially a bunch of knock that isn't shown as a knock signal because it happens between the log points? That significantly reduces the usefulness of logging knock signal

Yes, it's useless. I logged it once, but it's not clear what it's logging so I've not used it since. It may not even be filtered.

phrosty 06-16-2017 10:03 PM

OP2 logs with such a high frequency that you're not going to miss any knock.

steve99 06-16-2017 10:35 PM

Not sure if the OPis logging raw knock sensor input, if so its likely theirs a lot of signal processing done by ecu to determine if its a valid knock input or just noise probably looks at crank position ignition etc and applies a lot of filtering before its even decalred a valid knock signal then processed through the stuff wayno posted.

Kodename47 06-17-2017 04:57 AM

Quote:

Originally Posted by phrosty (Post 2930123)
OP2 logs with such a high frequency that you're not going to miss any knock.

If we can't determine if pre/post processing or have any control over the knock control system it's not really worthwhile logging.


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