I have a 81 245 glt and i am a new volvo driver so i haven't got a clue. when i bought the car the "sond" light was on and doing some research learned it was the o2 sensor. so i went to autozone and bought a new one but the light is still on. I've looked all over and can't find anything on how to reset the computer. i have disconnected the battery for 30 min and its still on when i plug everything back in. should i try an hour. anyways next question is about under the hood. I go to autozones website and enter my car info and the only option for the engine is the turbo model. not sure if this is turbo as important not familiar with it. the only thing under the hood i don't recognize is a black ball that is located under the manifold and injecters on the driver side. at the bottom is a tube coming from the air filter box and the top goes into the manifold. i have searched Google high and low and i can't figure out what it is. might be a stupid question but if its a turbo shouldn't i hear it spool up? thanks for all your help in advance.