engine makes a loud click wen starting on cold start HELP

[tye730]

so the other day i thought i would change my injectors clean and sand down my plenum to get rid of those rough bumps in there, clean throttle body and sand and clean the 6 trumpets and replace the inlet manifold gaskets put it all back together runs really nice but i noticed wen i start her on a cold start its starts fine but with a CLICK if i try turn the engine off straight away and start it again it doesn't do it again any ideas

[tye730]

oh and took out the pcv valve gace it a clean and the little plastic thing under it