rebuilt my sled put in new single ring pistons and low compression head. after putting it all back together i started it and it ran for a few seconds then died and wouldnt start again. tried switching plugs and got one big bang and could hear the turbo spinning after but that was it. started checking and found a piece of zip tie in between the head cover and head and a small coolant leak. fixed it and still no run. had put new fuel filter on and switched back but that wasnt it either. am i missing something? when it ran the afr was off the top. sounds funny when you pull it over and is harder to pull now. pull the plugs and it spins easy. do i need to do anything different for low compression head? give me some ideas please i would like to get this running again tomorrow