Backyard Rallying

All the lights and guages you mentioned are powered by a 12V feed once the key is turned to the "on" position. This wire is part of the instrument cluster plugs and all the lights etc are earthed by the sender units etc. I would check the 12V feed into the cluster as it may have come loose while you were behind the dash fitting speaker wires.

It sounds to me that the circuit opening relay is not working correctly when the key is turned to the start position. If this relay doesn't activate the fuel pump and the computer, then there will be no spark while the key is in that position. Also check the starter motor wire for a possible short, as the same wire activates the relay mentioned.

Another Corolla Driver in the family? 3 in Tas & 1 in Qld. :D