Hiya, Newbie here

I have a Civic 1995 (N) and in the space of sitting under a bridge for 4 hours after being driven 30 miles, it has died

Its turning over, but doesn't seem to be firing. There's no spark coming through the leads, we've checked the 2 power terminals under the dizzy cap, and 1 has power and 1 hasn't.

The 1 that hasn't power traces back to a plastic box at the back of the engine bay. Inside are several wires, some tubes and a breather filter. We have found out that a blue wire running from the dizzy cap is the one without power.

If anyone has any ideas or can point me in the right direction, you'd make me a very happy chappy!!
(Have fuel, battery fine, imobiliser is switching off and fuses checked)

This is quite urgent as the car needs moving ASAP and is currentl 30 miles away from where I live.

 

This could be a long shot but worth a try.
When you turn on the ignition (but not start the car) can you hear the fuel pump priming for about 5 seconds? If you cant it could very well be the main rely. This controls the fuel pump but it also controls wiring going to the ECU hence you would have no spark. Similar thing happened me. You should clearly hear the fuel pump turning when you turn on the ignition.It’s a common problem among civcs for this rely to go bust.

 

I believe the main relay controls power to the fuel pump and to the fuel injectors via the ECU. I don't think the main relay controls ignition/spark.