2010 Clubman S with N14 motor. Timing chain tensioner failed while car was driving. Replaced with Gen 2 Timing Chain set (this included dropping the oil pan to clean out debris, replacing all guides, flywheel, chain, tensioner, etc.) and used a tool that I bought on Amazon to hold the cams in top dead center. We did a visual inspection of the valves while everything was opened up, they didn't appear to have any damage. When we got everything hooked back up and attempted to start, the engine wouldn't fire, instead it would attempt to crank, and every 5 seconds or so there was a soft pop out of the exhaust. Help! I'm hoping this doesn't mean full engine replacement!

 

Also, I got an error code of P15E8 (P15E8 - Engine shutdown time, plausibility: Time too short relative to temperature drop in engine coolant)...can anyone translate this into English?