Holy ****!!
I just tried to start my car after sitting for a day and there was like a loud explosion that came from the intake side. Smoke came up from the engine bay and dissipated. Cannot pin point. Then I tried to start again and it did after a long start.
It was doing this once in a while since I put the injectors in but not so loud as just now. Can leaking injectors cause this? Too much fuel leaking into the engine from the remaining pressure overnight?

Or maybe too much damn fuel at start up with my tune