I don't know if the car made this noise prior to me putting the Zpi Crank Pulley on. Yssterday when I had my hood opened, I hard some sort of knocking noise from the engine compartment, I couldn't pinpoint where is was coming because it was really random. The noise went away after awhile. I dont know if it's the crank making that noise due to it not have the Oem heavier crank pulley. Any of you heard this noise?

 

Did it sound like it was coming from the same region? And do you still have your stock Crank Pulley, as slapping it back on in a matter of 10 mins could narrow down the solution to the problem. Typically speaking though, your car should not make a noise due to a lighter crank pulley, as I think you are the first to report a noise after crank pulley install. Slap on your OEM one, and see what happens.