Had the same with the Calibra V6 that we took the engine out of for the Astra conversion.
It would keep running with the igniton turned off, without the key and even if you disconnected the battery
The guy who stripped the Calibra interior, just ripped stuff out and cut through loads of wires, so we assumed that was the problem. The V6 is all wired into the Astra and runs fine - so whatever the problem was, it was on the car side of the loom, not the engine loom.
I would re-check everything you have touched when putting the OBC in, and have a good look round for any wires behind the dash that may of come loose or been broken, or any faulty earthing points.
318-is wrote:also, the two outside connectors for the OBC temp loom , the blue and black connectors, were on earth do they go, iv read the article and it dont make sense!
Do you mean for the temp sensor in the brake duct?