Knock Retard without Knock

FlashPro questions & answers specific to the 2006-2009 (US, UK, Asia) S2000
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hyperkin
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Joined: Thu Mar 11, 2021 12:27 pm

Knock Retard without Knock

Post by hyperkin »

Good morning / Good afternoon,


I am wondering, what could cause the engine to retard timing without registering a knock?

Recently had the crank and journey rebuild. On the same stock tuned map, the ecu started to retard timing much more often while knock level is lower than before. The knock retard highest is 6 at the moment, but only for a short moment, this is during daily driving, without VTEC.


Also, what is the knock level I should expect at idle? I am using the APP to track this.


Thank you,
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Hondata
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Re: Knock Retard without Knock

Post by Hondata »

Read this:
https://www.hondata.com/help/flashpro/k ... tables.htm
The way Honda knock control works is that you can get knock retard without any knock.

But in your case it might be mechanical noise. The knock level is not that useful, so you can only go off knock count.
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hyperkin
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Joined: Thu Mar 11, 2021 12:27 pm

Re: Knock Retard without Knock

Post by hyperkin »

Thanks,

So far, the engine is running without knocks. hope this will continue.

So should I use the knock level at idle as an indicator on tracking the rebuilt condition? I noticed the the knock level at idle went up slightly recently.
Hondata wrote: Mon Mar 07, 2022 9:07 am Read this:
https://www.hondata.com/help/flashpro/k ... tables.htm
The way Honda knock control works is that you can get knock retard without any knock.

But in your case it might be mechanical noise. The knock level is not that useful, so you can only go off knock count.
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Hondata
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Re: Knock Retard without Knock

Post by Hondata »

Hondata wrote: Mon Mar 07, 2022 9:07 am The knock level is not that useful
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hyperkin
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Re: Knock Retard without Knock

Post by hyperkin »

Thanks, can you share the knock sensor voltage that corresponding to 100% knock level?
Hondata wrote: Mon Mar 07, 2022 10:13 am
Hondata wrote: Mon Mar 07, 2022 9:07 am The knock level is not that useful
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Hondata
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Re: Knock Retard without Knock

Post by Hondata »

It's not that simple. The ECU determines there is knock based on a crank angle window when knock is likely to occur, and the threshold varies based on rpm and load. The logged noise is just an average of the knock sensor reading without the conditions, threshold or window. I've never found it to be useful.
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