1998 chevy k2500 5.7



engine cranks but will not start, it kicks back after cranking over for a couple of times i have replaced the crank sensor it has done this once before it kicked back hard enough to knock a tooth off of the flywheel after replacing flywheel and starter it started fine for three months then it kicked back hard enough to break a starter mounting bolt. i replaced bolt had starter checked nad replaced again any ideas?


Recent rebuild or 200K on the engine?


Make sure the crank sensor pigtail is good. Could also be the distributor cap.




Any reason to believe that this isues is NOT related to wear in the timimg chain (like you have inspected or replaced it already?)


timing is correct this happened once before then started and ran fine for four months. then it would just crank but not start,


I am talking about possible slop in the valve timing. This would take someone more seasoned that myself to make a call on a worn timing chain/gear simply by moving the crank and seeing how closely the distributor followed it (with delay or without delay).

Backfiring through the carb says the firing event was not happening at the right time (as far as the valves are concerned).