E87 timing

After replacing the timing chain on my 116i e87 the engine will not fire turns over but will not fire .having said that the first time I turned the engine over after finishing the chain .it started and within seconds it cut out .
Prior to replacing the the chain it was running really rough and make quite a noise and cut out when warm and would not start until cool
Anyone have any ideas .
Ps not sure if I have the timing spot on ?
Done the usuall locked the crank locked the cams .how do I know I am not a sprocket or cog out.
Any pics or advice would be appreciated or help .anyone live in Hampshire 😀That has some time ha!