Hi, have you reset the mixture screw on the ecu?
I had a similar problem and it was down to the mixture screw not being reset and setup, on L8 it's 5 turns clockwise and approx 2 1/2 turns anticlockswise for a ball park figure, and L6 i think is opposite but you will need to ask as i'm not sure, you MUST check fuelling after doing this as you you don't want to melt your engine if it's running lean.
Hope this helps.