BMW Repair: BMW still wont start, air flow sensor, bmw shop

Question
BMW 1996 318i touring 173000
its been great until now.. it wouldn't REV so we came home and here its sits.
A Diagnostics Firm came out and we replaced the following.
 Air Flow sensor plus the whole unit, the throttle body and the ECU plus new spark plugs.. it does try to turn over and all you smell is Gas.  He himself doesn't understand why it is not starting, which it should after replacing all the above..  CAN YOU PLEASE HELP AND GIVE SOME IN-SITE ON WHAT IS GOING ON.   Thank You  

Answer
Laura, Do you have good spark? Fuel delivery, pressure, volume? Injectors pulsing? Good compression? Try tapping on the idle valve next to the throttle body and see if that does the trick. If you are smelling raw fuel then injection is PROBABLY okay, but needs to be checked. Is the engine cranking over at normal speed? What is battery voltage? What faults do you have in the system? A lack of airflow from the idle valve will cause a no start, but if you put your foot to the gas usually it will start, just not idle. Have you taken the car into a BMW shop or dealer?
-Evan