Vr wagon not starting

[Simvrlexcen]

I have just bought a vr commodore wagon i had to replace the intake manifold gaskets i have had it running since it was running fine then stalled and has not fired up since. I have spark and fuel. When i bring up fault codes it says 12 which says its fine but it still doesnt start.

[edals]

I am assuming its turning over, but just not starting?

[woteva]

Check wiring connections etc.
It is cranking but not firing ??