starting problem

So my car was put in the shop for not starting and now its not starting again. I put a new battery in there, just got out of the shop for a battery distribution part and it has new spark plugs. when its cold it really doesnt start at all, rearly. So what do you think it could be?
when you turn the key over, it just keeps trying to turn over. with rev limits starting and staying at 0 and moving up and down between 0rpm and 500 rpm. If I get luckey enough it hits over 1000 rpm and starts. Tonight I kept trying to start it and then I saw smoke from the exhaust, under the car, and under the hood.

Have you tried changing the distributor cap, rotor, and wires???? Have you ruled out a faulty fuel pump?

ive got the same problem before, fuel pump no problem, fuel filter no problem, the authorized bmw repairer did vanos solenoid replacement, and ecu cleaning, they also changed vacuum hoses, and changed 2 relays for the icv...well thats what they told me....maybe i was ripped off, i have no idea.