Car runs for a few seconds then stops

[E-bmw]

Joking aside it could be that you have air trapped in the fuel lines, never heard of it before but can't think of anything else.

With many injected common rail cars there is a shrader valve at the end of the fuel rail above the injectors.

This looks EXACTLY like the one on your wheels, and to open it up you need to carefully depress the pin in the middle of it.

If this is the case with yours start the car & then when it cuts out quickly depress the pin in the valve & hopefully you may get air out, you may need to do this a few times before you get good fuel flow out of the valve, then give it a try.