Knock trim while no threshold is exceeded

[skeruno 0]

Hi there,

 

Maybe you have some insight in this. I see knock trim while the noise is not exceeding the threshold. In the attached example you see that cyl 5 does exceed the threshold but all cylinders show a trim. You guy's have some insight on this?

 

An other question, while im at it: on a warm start(ECT:90C) the engine is running lean for a short period of time(2 mins) which is normal. Is there any way to compensate for this?

 

Thanks a lot!

 

Kind regards

[remski2 6]

Look at your:

Advance delay

Advance rate 

in the Knock Setup section.

[Vaughan 61]

If that's a PCLink log then it is possible that knock occured on all cylinders but the log wasn't fast enough to capture it.

Have a look at the post start enrichment settings if the engine is lean for a time after startup.

[Ducie54 74]

Knock threshold would have occurred in a earlier part of the run. It then is applied to that cell each time after unless reset. All in the help file. 

 

[Rob W 6]

Do ECU logging for the same selected parameters at 100hZ and you might see it will pick up the knock event. Had the same issue.