Hello,

Recently, I'm in trouble by this kind of knock.(Please see below pic.)

1. It occurs when I loosen the accel pedal and the throttle begins to close after wot or half throttle.
2. It continues, consistently occurs under above condition.
3. It has 3, 4 or up to 5 of max knock count.
4. So far, it occurs between 2000rpm to 4000rpm.

What could be cause this kind of knock and what should I check? For this poor novice, could you give me some advices?

Thank you.

a sample of the knock:

 

can you make the image bigger? its hard to see

 

Would be helpful if you log ignition timing

But for me it doesnīt look like knock.

More like "pink". Donīt know if there are other words for this in english.

I would listen to it with headphones to make sure what it really is.

 

tephra,

Sorry, I re-linked to more large image(sample 1) and added sample 2. (Don't be surprised at laaaaaarge images.)

After logged sample 1, I changed my 'Open Loop Load High Octane' tables and logged sample 2. as you can see on the sample 2 image, I guess the knock occurs at the boundary of the load(increasing to decreasing).

I don't change the gear at that time. I took both logs with keeping 4th gear. It's not shift knock.

 

Hello, Schneider. Thanks to replying.

Sorry, I didin't logged the timing for sample 1. I re-logged sample 2 with the 'Timing Adv' row. Please see it.

>I would listen to it with headphones to make sure what it really is.
Sounds like a sonar! Because I'm not a tuner, just a DIY newb, I don't imagine how to use your headphones to listen to the knock music!

 

He is referring to det cans (its an audible knock sensor).

I'd say pull back timing slightly there, if it doesn't go away its probably phantom knock.

 

Thatīs why I think itīs no knock

If your LC-1 is right, then youīre running very rich at that point. What kind of fuel?

 

In Japan, we use 100ron(about 93.5aki?) gasoline for 'high octane' specified cars like EvoX.(We have just 2 type of gasoline. 'regular'(90ron) and 'high octane'(100ron).)

>If your LC-1 is right,
Though I calibrate it regularly(once per a month), I'm not 100% certain. Roughly 80%?

 

With that AFR and Timing I can go on 98RON without any knock

 

Thanks. I guess you think it isn't a real knock. If so, though I'm glad, I can't find a way to determine what causes the sensor to always show some counts of knock under the same condition. no need to worry it?

 

Hi,

>He is referring to det cans (its an audible knock sensor).
Thanks to the info. I've never seen a 'det can'. Though I can't imagine how expensive, sounds very interesting.

>I'd say pull back timing slightly there, if it doesn't go away its probably phantom knock.
Thanks to the comment. I'll try to test it.

referring to Schneider's advice, I've just modified the high octane fuel map to be more lean at spool and peak boost area. Interestingly, the knock sum count reduced to 1 or 2.(before modifying the table, up to 4 or 5 counts of knock had been showed.)

Because I am stupid, I don't know why it was reduced. But I learned suitable afr for spool and peak boost areas. I confess because of the notes on the second image showing the ignorance of me, I was ashamed of that. But I chose to show it to get comments from ecu gurus was better than not to show it.

 

There is such a thing as knock from being too rich or having too little timing... but on standard pump gas these instances are sometimes harder to find.

 

Funny thing

This thing is not called knock. I donīt know the right word for this in englisch.

There are 3 phenomenons that can make the sensor work. Only one of them is knock.

Ok 4 things with phantom knock

 

Thank you for the comments Schneider and fostytou,

>This thing is not called knock. I donīt know the right word for this in englisch.
I just noticed you are posting from Germany.

Those knocks are maybe "phantom knock" as fostytou posted earlier(thanks fostytou) and probably was caused by too rich fuel.

Now I'm adjusting "High Octane Fuel Map". I think "Calibration Fuel Map" are also need to be adjusted.

Thank you.