I just installed one in my 2002 civic lx, and now when the engine is running the check engine light stays on. How could i have installed it wrong to make it do this? Could i have grounded a wrong part?

just disconnect the battery(both positive and negative) for like 10 mins then reconnect it and start the car. if it comes on again then take it to a shop or autozone and see what code is it throwing.

what's an engine grounding kit?