Had my FD for about one year stored in the garage, as yearly garage cleaning came up, we had to get the cars out of it. So I reinstalled the battery and started her. Out of the garage I let the motor on for a few minutes and started reving a little, only until +/- 2.5k. Suddenly the engine died. Few hours later I started her again without problems and drove back into the garage.
Does anyone know the reason why the engine died?! Was the battery to weak? What else could it be?

Many thanks for any advise!

 

Without Datalogit logs of the incident, we can only speculate. Did it die after you let off the gas from revving it? It could be an idle speed related thing or a brief lean condition. If the engine wasn't fully warmed up when it died it could have gone too lean due to the adjustment of the water temperature compensation table. That's not dangerous for the motor or anything, it's just annoying to have it occur.

Based on what you've explained there's probably nothing "wrong" with it. Y just experienced a stupid little quirk from a modified engine with an aftermarket computer. Some adjustment in the PFC and possibly adjustment of the throttlebody might be able to help. There's not enough information to say.

 

A weak battery?

Only if the alternator was not working properly.

Any stored car should have its engine started more often than once a year.
Hope you changed the oil/filter before storage.

Might have died from your neglect of it.