Little sister in college has a '91 740 turbo. Her engine sucked an intake hose clip into the engine and killed the head and a piston. She left the car at my house as I offered to replace the engine for her. I acquired a '93 B230FT long block including all accessories from a 940 via ebay from out of state and had the engine shipped here and I have just finished installing it. I replaced the timing belt and gave it a general tuneup before installing it.

I tried to start it yesterday and it would not start; sounded like timing was obviously advanced. I double and triple checked the timing belt and it was in correct position so I backed off the distributor timing a few degrees. It will now start but will only run if I keep a heavy throttle. I figure this is a vacuum issue now, and I have spent two days verifying everything is connected, and that everything on the '93 engine exactly matches the '91 engine.

Are the '93 engines compatible in a '91 car. I assumed so, but this is crazy, as I can't find a vacuum leak or sensor/port not connected. I am matching everything to my personal '91 745 turbo as well to make sure it all looks good, I can't find a thing.