knock input voltage

[ssddaa]

if the knock sensor is Mitsubishi MD 159216 also is given the knock gain is 1.00, set up at 7kHz and sensor is reporting numbers between 180 and 225, what is the voltage from sensor at V88 knock input

 

[Adamw]

The numbers arent directly related to voltage as it is passed through various filters first, then only sampled during a small crank angle (knock window) before being processed into a "knock level".  The voltage at the actual pin will be much higher than the processed signal that the knock level number is derived from.

 

BTW, I deleted your post with the same question from the G4X forum.

[ssddaa]

Hi Adam

I swapped the engine and as you can guess new has different parts. It shows now random knocks (2-4) sometimes when TPS is less than 40% and slight deceleration . The two tuners that have seen the logs are puzzeled. The only sensible suggest so far was from Ray Pampena who modified many of these engines "What is the knock voltage that you are seeing?"

What should my answer be?

Thank you in advance

Stefan

[Adamw]

I would suggest you get someone to connect audio knock detection to the engine to confirm if there is any knock and calibrate the knock control system to match the new engine.  There are many factors that will affect how much mechanical noise the engine makes and its knock signature so you need to calibrate the knock system so that it only indicates knock when there really is knock.  Piston to bore clearance, drivetrain backlash etc will all vary significantly engine to engine.  In fact even seemingly unrelated factors can have a big influence, there is an article in one of the Motec manuals where the best knock detection frequency for a mitsubishi evo changed from 5KHz to 6KHz just from fitting a rollcage and different exhaust system...