BMW Repair: post intake manifold removal 530i 1994, fuel regulator, intake manifold

Question
Just finished putting it all together. Replaced all gaskets and pcv plate.Cleaned intake and all surface. Result backfire !!!! and engine wont run. Check the plugs all black. Thinking of changing fuel regulator.

Answer
the fuel press reg is a good idea but I don't think it would have failed because of this repair. I would think fuel or cleaner got down there during the repair. maybe take out the plugs and fuse for the fuel pump and crank engine for a while then let it dry out awhile. maybe spray out with compressed air. reassemble and try to start.
           Kimber