Confidence votes 131. The cam sensor tells the computer where your cam is in it's rotation. The info is used to determine spark timing and fuel delivery. if it's bad, you'll run rough or not at all.Vehicles with distributors will sometimes integrate thet sensor with the distributor.onfidence votes 131. The cam sensor tells the computer where your cam is in it's rotation. The info is used to determine spark timing and fuel delivery. if it's bad, you'll run rough or not at all.