Make sure that round plug is in.
May sure your supply is on the back of the rail.
Vacuum leaks will make your car run like a bag, but it's gunna run.
Here's some info from strictlyeta.net and their 2.7 L build.
Later model 325i's use a secondary harness just for the fuel injectors, unlike the 325e's wiring harness which connects directly to the injectors. Because of this, you should use the 325i fuel rail because the 325e's fuel rail has an outlet for a return line right next to the #6 injector. If you do use the 325e rail, you'll have to figure out a way to wedge the 325i's harness rail underneath it without breaking anything.
Earlier wiring harnesses (1987 and 1988) had individual connectors for the fuel injectors and do not have a secondary wiring rail. If you are using this earlier harness, then you may be able to get away with using the eta fuel rail.