Went lean...
I'll try to get some pictures tonight, if I can get to it before dark.
YES! My ability to be clear is not great. Your comprehension is great.
Yes. It did as you state.
I can understand this totally. But mine did not exhibit this. It responded to the change in AFR. Sounds like my engine responded to some unknown change. Your engine's performance responded to a sensor that was lying.
The sensor doesn’t lie. It can only measure oxygen content in the exhaust. So it can’t tell the difference between a lean miss and being rich because there is so much unburned fuel left over from the misfire.
That’s what I’m trying to get across for anyone using an O2 sensor. Just because it’s saying something it doesn’t mean that what’s actually happening.
I’m still looking for the other paper by Shrinker. I know I have a copy at home. In it he discusses working with an engine on the dyno and the O2 was saying one thing but the end of it was something else was happening. It s a great paper.
My point is just don’t take the O2 sensor reading as gospel. Look at it and then look at everything else around it and then you make the decision on what’s happening.
You can get into a similar situation with EGT’s. I had a customer call me one day from the track and his EGT’s were horribly high. Like over 1500 degrees or something. I asked him what the plugs looked like and he never checked them. So I asked what was doing to lose them and said he was adding fuel and pulling timing.
So that was the answer. He had delayed the combustion process so long that there was still combustion happening when the exhaust valve opened and that was what the thermocouples were reading. They weren’t wrong. The tuner just didn’t correctly assess what the data really said.
So I had him add timing and pull a bunch of fuel out of it and the EGT’s were right back in line.
It’s easy to get data overload and become data dependent. One or the other isn’t good, but if you happen to be at a place where you are doing both you can get lost very quickly.
Hopefully that clears up my original post.
