would a bad crank and cam sensor keep my car from starting? 97 5 speed maxima will crank hard but not turn over. cel codes are knock cam and crank sensor.

 

Those are common causes of cranking with no starting. Replace them and try again.

 

Pulling the crankshaft and camshaft position sensors out and cleaning them might help. They tend to get covered with metal particles. Knock sensor won't affect starting.

 

Indeed, if you do so much as search, you'll find that these are often the cause of a no start condition.

But that requires one to actually use this feature: http://forums.maxima.org/search.php

Clean them first, inspect the timing rings on the crank and flywheel. The CPS shouldn't have much of anything on it, considering it's soaked in oil most of the time.