i have a 91 honda civic dx. it wont start and when i crank it over it backfires. i thought it was the timing belt. but i took it apart and the belt looks fine ive checked the plugs and they are ok as well. the inside of the distributor looks ok to. im lost i dont know what to do from there.

 

The timing belt could have skipped. With the upper plastic cover off, turn the crank (using a socket wrench on the crank bolt, and turn counterclockwise) to TDC then check the marks on the cam pulley. If the "UP" is at the bottom you need to turn the crank all the way around exactly once and check again.

 

witch one do i need on tdc?

 

The crank to TDC, which is the single mark on the accessory pulley. Leave the accessory pulley and lower plastic cover on for this test. You can also remove spark plug #1 and probe in the cylinder to determine that the piston is all the way at the top.