So my ecu is all confused... Both LEDs are on all the time and when I turn ignition switch on they light up brighter..... Start the engine and they disappear.... Car is stuck in limp mode Aswell.... Can't access diagnostic mode. Any help would be great. Are LEDs meant to be on with key out of ignition?

How is computer getting volts from eccs relay with key out of ignition. Whats changed?

I dunno... I deleted the datsun voltage regulator and a few other bits out of the factory loom. I think it must be an earth problem

I someone could tell me the cycle for the LEDs? As in when keys out of ignition are the ecu LEDs still on?
When engine is cranked.
When engine is rubbing
When engine switched off

The LEDs are supposed to be OFF when ignition is OFF.

The ECU voltage feed is supposed to be IGN. If instead it is connected to 12V unswitched, the LEDs will stay on. So check that first.

This datsun will be the death of me...

It's not the Datsun's fault ... it's the NISSAN's fault

Like it's not the car that usually causes the crash .... it's the 'nut' behind the wheel

you should check out the S13 FSM (Factory Service Manuals) they are easy to find on the various silvia forums