Lots of cranking

Hello all I have a 92 4o 5sd had it about 2 mo now when you go to start takes a lot of cranking have read post about this have tryed the key on till fuel pump stops then try it . sometimes help but not much.have read its CPS or Cam sencer dose any one know how to check it what the oms or to be or the votage have looked on past post but no help. Seems like its hard on the starter have to do this. any help thank you