weird knocking in L12b

  • hey guys ,

    i have honda amaze with same brio engine L12b . i have installed a small conical pipercross air filter and a nitto axle back exhaust. lately i have noticed that whenever i drive my car with A/C on , in third gear my car gives weird knocks / minor jerks . this is only when rpms are below 2500 . once the rpm goes above 2500 this problem goes away.

    what you guys think ? is it due to the air filter?

  • Hi gautamracer, welcome to Honda Brio Community.
    Changing air filter means changing air - fuel ratio, normally the ECU will adapt itself to amount of air coming into combustion chamber, but... it needs time.
    Knocking in your engine means that the air fuel ratio is too lean, and it gets worse when engine load is bigger, ie when AC on.

    There is a way to make your ECU adapt faster:
    1. Try this procedure when the engine temperature is low.
    2. Start the engine
    3. Hit throttle pedal to 2500-3000 RPM and hold until the extra fan spins.
    4. Release throttle pedal, then turn off your engine.
    5. Restart the engine.
    6. Done.
    7. Tell us if it works

  • Hey admin , thanks for your input. I tried your method . Initial observations are as follows-

    1. Car jerks/knocks in 3rd gear at about 35km/h , rpm would be 1500 or less , with or without A/C.

    2.Overall performance has increased.

    3.When I engage first gear , the moment I used to release the clutch there used to be shuddering with or without A/C. Now that shuddering has gone.