is it possible the car knock at the rev limiter

phurmula ks3 knock detection kit and its telling me knock everytime i hit the rev limiter is it a real knock? or just a noise from the the backfire or any background

at rev limiter, the ecu limits the torque by various methods. Having said that, it is VERY unlikely to be real knock what you are hearing exactly at the rv limit threshold. More likely, the "microphone", which indeed the knocksensor effectively is, is picking up on the accompanying noise (backfire, etc).

Can you post a graphical engine noise profile here?

I have the ks4, and i get a big spike at the rev limiter too. Thats why i patched it thru to my dyno, so i can see what its putting out thru the entire run (=.

It's pretty unlikely in my experience. There is a lot going on when the ECU is fuel or ignition cutting to limit rpm though and this can trigger a knock detection system as it is inherently quite noisy. What are you using to limit the rpm? Fuel or ignition cut?

My KS4 also go nuts on the rev limiter. ECU knock log doesn't pick up any knock... Guessing the KS4 doesn't like rev limiters much!

im using fuel limiting to backfire when hitting the limiter