I found an interesting feature with my new car engine. It's done less than 50 miles so is not even close to run in or tuned (so I know there's loads of work left to do, including finding the 10% bias in fuelling between the banks) but I did expect it to behave the same way on two occasions on the same day.
Run 1 - half past 7 at night, air temperature around 3 degrees C.
https://dl.dropboxusercontent.com/u/8968424/vems/v3.3_u004371-2015.02.02-19.26.23.vemslogRun 1 - quarter past 9 at night, air temperature around 1 degrees C.
https://dl.dropboxusercontent.com/u/8968424/vems/v3.3_u004371-2015.02.02-21.14.52.vemslogin run 1 the car ran quite rich (as I wanted it to do when running in) such that the average EGO correction across both banks was around 95%. Idle was high for some reason, and the IAC couldn't reach target. EGO correction maintained good mixture throughout the drive and didn't appear to be biassed by air or coolant temperature.
In run 2, the car ran quite lean such that EGO correction averaged 103%. This is much less good! Again, there looks to be no obvious bias from anything the ECU is measuring.
You should be able to see that no tables were changed between the two runs - so why is the car behaviour inconsistent? What am I not measuring or seeing?
My first thought is that the cam sensor is not working right and the engine synchronised differently, however the cam sensor looked to be reliable when I tested it during installation.
My second thought is that fuel temperature has a much bigger effect than I thought - the car was warm for the couple of hours between runs, so the fuel would have become hotter, and there would have been less fuel for the same injected volume.
Any thoughts?
Thanks