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Vipec knock interface


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Hi - Just going through the process of setting up my Vipec digital knock interface with my V88 and would appreciate some help.

The first query is regarding the knock frequency -

I have recorded and analysed several instances of knock all appearing clearly at 11.3 Khz. This is odd however as my cylinder bore is 84.5mm - putting the calculated frequency at around ~6.8 khz, or ~13 khz 2nd harmonic.

Is this due to my knock sensor type? - (I am using stock siemens sensors, the engine is a BMW M54B30). I am unsure if I need to set the knock filter at 11 khz narrowband or use the 2nd harmonic wideband setting?

I have attached 2 instances of knock (recorded in wavepad).

The next problem I am having is the ECU does not appear to be receiving a digital knock feedback signal from the knock interface, I have checked wiring and software settings, but the ECU is not seeing any frequency reading from the input, so the knock system does not work. - I will hook a scope up to the knock interface over the weekend to test the output - but just wondering if there is anything else I should check or is there a way to test the interface?



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Made a little progress - I have got the interface to work with the Vipec but only intermittently. It appears the ECU is disabling the knock control on about 50 percent of startups because of a DI5 pulllup error.

The knock input is configured to DI6, and pulllup is turned off so I don't know what is causing it to be disabled intermittently.

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