Forum » EFI Tuning Fundamentals » OEM Resonant Knock Sensor - Loud @ part-throttle, quiet @ WOT. Why?

OEM Resonant Knock Sensor - Loud @ part-throttle, quiet @ WOT. Why?

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ECU: AEM Infinity

I am literally banging my head against the wall. Please help. My 4yr old resonant F22 (AP2 S2000) OEM knock sensor is more quiet at WOT than at part-throttle.

My S2000 customer(s) knock sensors behave as expected. I can tune their cars just fine however my personal car knock sensor is a straight up rebel.

1. Second harmonic @ 13.14 KhZ got me enough of a signal boost to, at bare minimum, know what is happening and to see each cylinder talk.

2. Amplified Gain bumped x2 & Integrator (smoothing) Time modified

It is smooth as butter under WOT, it is loud (chatty) at part throttle and it defies all logic - impossible to set the knock floor. I have fresh engine mounts, OEM built engine and I have disconnected my supercharger belt.

I use LINK Knock-Block audio detection. I know it's not knocking however I just want to understand what makes my OEM sensor so silent?

My client Hondas behave as expected... yet my personal car at double kHz, increased Gain & Intergrator seems to still be silent. What gives?

Hello this is pretty interesting and no something i have come across before

have you tried an other sensor like the bosch sensor to see what that shows ?

Sorry for the delay, I just kept on playing with frequency and completed the tune by relying on Link Knock-Block.

I might just switch to the Bosch sensor... granted, OEM sensor use is my preferred method but for no good reason. Just because I like sticking with OEM.

I will post a screenshot shortly as I would love to hear your take on the current signal pattern.

Attached to this post is the comparison.

Left example is the norm and right example is my car. I had to bump everything up just to get this resonant sensor to talk.

Please let me know what your opinion is. Pay attention to how on the right map (my car) the part-throttle (cruise) knock-volts are close to my WOT noise. Is that normal? I can confirm it's the same with audio-knock detection.

Could folks with more experience than mine please confirm that it's normal for engine noise to hunker down as you go WOT instead of getting louder?

EDIT: The map on the left had no knock protection configured. I ended up configuring knock-floor for this customer as his tune was... well... interesting and none of the protections were setup AND this is with a big **** turbo. Boy o boy.

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