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Feedback Knock Correction Question

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IAG 700+ forged full build

As seen on the image attached i once in a while see these Feedback Knock Correction 1byte/4byte they read the same showing that a correction to a precived knock i would assume. No Roughness was triggered and Fine Learning Knock Correction also did not adjust and no Knock count was recorded either and it is always in the same type of place top graph where i am off engine load in yellow and RPM's are headed down in green lower graph yellow requested torque.

Could this be forge false Knock ? What could be causing this. I have retarded the timing to very low numbers as well as advance timing and it always shows up in the same place at random times and i do not belive its a real knock.

Its a very small and quick correction as well that returns to its normal setting as fast as it kicks down.

Attached Files

That is an engine noise that triggers the knock detection. You are off the throttle and not under load, I would not worry about it.

Scott, a few suggestions.

The knock event precedes the response and your logging rate is likely extremely slow, so keep in mind the event the ECU is responding to happened before what you see there, and the response continues based on a time delay, so while the timing is mostly retarded after you lift, the knock that caused it happened prior.

Retarding timing is a good test. I also suggest you take a lot of boost out, along with conservative timing in the area you'll hit at lower boost, and see what happens. Timing won't necessarily stop an unwanted event if your issue is induced by extreme heat, and dropping boost way down will allow you to narrow that down.

And to throw another possible cause in the mix, I don't know what valvetrain you have, but dropping the boost will also reduce exhaust pressure on the backs of the valves in case that was causing valve float.

So i have a fully built IAG 700 Forged build.

I have tried most including removing boost and it still randomly happens in the same pattern as above image. Funny enough adding more boost seems to keep it from happening as much. And i am not even close to where my boost will be once i swap out the turbos.

I have my adjustable blow off valve set to its max spring rate due to the bosot that i produce but when not using full boost i wonder if it might be an adjitator to this but this is a guess and when i do lower the blow off valvue spring rate it seems to make it a bit better but stil is there but then my targets have issues. So catch 22

It's possible your BOV is a large air leak causing the turbo to work a great deal harder than the boost you're seeing suggests, which can cause knock. The adjustable ones generally have not worked well in my experience. Have you tried a boost leak test with smoke while viewing the valve at perhaps 5 psi over boost target to see what it does?

I have not just ordered a smoke machine to just have and see if there are leaks anywhere in the system

So finnaly found the issue those darn banjo bolt filters all but one was removed and the one was on the vvt side and it was not progressing the same way as the other side causing a small hickup that it picked up. Car now runs great and vvt which i now log are showing them moving in tandum. Was fun to debug since i was not logging VVT intake and exhast so never noticed one side was stuck on 10 deg while the other side went up and down thru the range set in the rom.

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