[olddog]

I been reading some more stuff. I have been very confused, as different authors lead you to believe different things that they never state for certain. Many times I read that the factory O2 sensors can only read in a very small range around 14.7:1 AFR. No one ever says just how far from 14.7 they will read!

So when you are running at say 13.5 AFR, the big question is: can the O2 read that you are at 13.5 or is it out of range? When you read how the AFR is fattened up as the load goes up on the engine, you have to wonder if it is within the range of the O2. If not then it has to be running open loop. If the O2 range is as tight as some lead you to believe, then under most conditions your in open loop. It just so happens that under normal driving conditions in a factory stock car it is in a condition to run in closed loop (I understand that this so happend by ford engineers designs). But my point to this is that when we get into highly modified engines, cars, etc. we may rarely be in a condition that it runs in closed loop.

From your question on where your AFR is at, do you know what the O2 are reading? Is it open or closed loop at that time? You said your closed loop AFR is 13.5, but are you sure it is in closed loop or just assuming it is?

Wish I new more.