Bad Earth, I Think

[saveloy 8]

I'm running an Omex 500 ecu on my 8 valve turbo.

It's mis-firing and struggling to rev under full load. Checked on the laptop, the map and throttle readings go mad with the engine running. But are fine with just the ignition on. The wiring for the ecu and sensors has been checked and passed off as fine. I have changed the coil pack, tps, cps and map sensor. I have checked the plugs, lambda, air and coolant temp sensors. With no joy.

The earth block behind the N/S headlamp is fine.

I've run out of ideas.

[Tom Fenton 1,542]

Have you got a decent thick earth from the ECU back to the battery? Sometimes you can get weird earth loops, tying everything back to the battery may help?

[saveloy 8]

Tried an extra earth cable from ecu to battery - no joy.

Re-wired the earth and signal wires of the map and throttle position sensors straight back to the ecu and there was no change.

Which other of the ecu wires could cause an interference issue like this? If I was 100% confident it was the Omex wiring loom I'd purchase another and re-wire the lot.