It is using a special code for all engines as only #1 will start with the usual CTRL E in FS 9, (the usual result of a non default satrting code) as many of our model here won't due to their own coding.
Each engine has to be started separately and in the case of the APU it is probably slightly different to the other engines.
In FS9 it starts just fine using the procedure but sometime thing you'd expect to come across in FS.X don't, but any modified code published should address any issues
Garry
"In the world of virtual reality things are not always what they seem."
I seem to remember (it was a long time ago) that the default jet start code was different between FSX and FS9, and initially when FSX was released, the like of the VC10 wouldn't start. I found this out again recently as I managed to end up using a really old version of DM's VC10 CAB when I rebuilt my computer. I re-downloaded the current one from DM's site and all was well. Its worth mentioning also that the current VC10 start code works in both FS9 and FSX so I'm not sure what the difference is. The behaviour (on the VC10 with the old CAB) was that the engine would spin up to the point where the fuel flow would get switched in and just stick there. I'm guessing (and its just a guess) that the problem would relate to when the fuel flow starts for the engine.
It's generally to do with the starter code; FS9 toggles the starter on and off repeatedly until the engine lights, whereas that won't work in FSX, you need a separate command to turn it off again, so processing, as opposed to mouse click commands don't work.
It appears that the engines DO use the same command. This code fixes engine 1, and if you swapped every 1 with a 2, it would fix engine 2. I will see if I can figure out how to get the APU to work using this principle, as swapping every 1 with a 3 will NOT work.