Car amp install help.?

ok so i got a 250w sony xplod amp and really old mtx terminator 10 in subs but i have to turn it up really loud and my front speakers start to crackle yet i turn the subs on and off and there is no difference, i did notice the power light on the amp is "dim" compared to the hook up in my room( and yes there is audio comming from the subs). i did not remove the paint on the chase for the ground plus i dont think its exactly on the main chase either. will complete grounding change anything?