oh if fails to turn the engine? then does so a few minutes later? check the grounds on the bell housing, theres 3 wires there, 1 fat neg bat cable, and two smaller. make sure the nut is tight, and the ends of the 2 small grounds wires are tight to the eye loop.

if those are ok, check the pos cable on the starter.

and of course clean your battery terminals make sure those are also tight.