i did the test on mine with a timing light and a hammer. before i tapped the block, the marks on the pulley were jumping around.....whatever that means, but when i tapped the block with a hammer, i understood it should have went backwards or whatever (retard timing) which never happened. i will try to put my new one on today. although my car is not "slow" because of this. im just getting really S***** gas mileage.