0.04v O2 WOT figured out

[Coldandafraid]

Well, after a week of cautious experimentation with the afc settings I have finally found out why I was getting 0.04v O2 at WOT. It turns out, that if my fuel is perfectly tuned to my boost, I get good timing and O2 readings, however, if I am just a couple percent above what it should be, instead of my O2 readings going up to 1.0 v, it actually goes straight down to 0.04v. So, basically, if I am too rich, I get nothing on the O2 reading.... which caused me to add more fuel at first, making it worse... so I added more, and I got rich knock, timing when down, car started hesitating... so, I got brave and took all the fuel away, and I got real knock! So, I added bit by bit till my timing came back. However, its still very hard to get it exactly right...

 

[azteck2]

that makes alot of sense, i'v been trying to find why i'm getting knock at mid throttle and i keep riching it up and it's getting worse, i'm going to try what you said this weekend when i'm on the dyno.

 

[kpt4321]

That's why you don't tune by O2 voltage.

....Kyle T.
93 TSi AWD "TURBO4"
14b - 12.8 @ 108

 

[nowayout]

I don't utne to O2.

I mainly use knock, timing and inj/pw.

 

[Turboniam]

Same thing happened to me when I was WAY WAY too rich.

 

[Coldandafraid]

yeah, but for me, its not WAY WAY too rich, its basically 1% on the AFC difference.