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Author Topic: Knock voltage on 3  (Read 2720 times)
opticaltrigger
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« on: January 23, 2017, 02:40:00 PM »

Hi guy's
Iv'e been looking through a few logs of my own and other peoples and noticed that the knock voltages from cylinder number three seem to be consistently higher than the other cylinders (1.8Ts that is).
I was hoping to get any thoughts on the reason for this.Perhaps I haven't looked at enough logs yet but there does seem to be a pattern to it.
Is there any particular reason for it anyone knows of.

All the best
O.T.
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veigy
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« Reply #1 on: March 12, 2022, 03:56:49 AM »

Hi, I see same behavior on mine car. Did you find out something?
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prj
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« Reply #2 on: March 12, 2022, 04:32:07 AM »

Stop looking at knock voltage because it is completely irrelevant.
It is heavily influenced by where the knock sensor is located physically.

"Knock voltage" base level is not used for knock detection. It is an integrator with peak to peak measurement, and what matters is the factor between the minimum and maximum level in the knock window, not the absolute level.
And sure as hell you should not be comparing it to other cylinders because it means absolutely nothing. In fact there is a pre-amp on the knock input, and chances are that the pre-amp level is just set to different levels between different cylinders.
« Last Edit: March 12, 2022, 04:34:16 AM by prj » Logged

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