Why do my o2 readings jump?

[Cool Mr Steve]

Ok, I'm trying my best to log my car, and I am having no luck. My car is stuttering and where it stutters my o2 shows that I am lean. Right now I have my SAFCII (with 550cc injectors) set to +4% all the way across. By the way, if anyone has any idea why I need to ADD fuel to my 550cc injectors, jump right in... Anyway, it's rainy and trafficky around here, so this is my pull to almost 5000 rpm. I probably could have pulled it more, but the stuttering was more like a long hesitation and it was scaring me. If anyone has any ideas why my o2 jumps so akwardly, please let me know.
RPM Timing O2
2752 10 0.92
2884 9 0.92
3000 8 0.94
3132 8 0.94
3324 4 0.94
3456 4 0.94
3732 4 0.96
3900 5 0.94
4148 7 0.96
4276 8 0.9
4484 8 0.98
4992 9 0.98
4768 9 0.24
4928 9 1
4824 9 0.98
4692 10 1

 

[1LE]

Why do you have to add fuel? Looks horribly rich to me. Timing is horrible, but that can happen when you're real rich too. If you want to know for sure, you need an accurate way to measure AFR.

 

[Pure92TSi]

Yeah it was way rich. Lean it out a good bit and see what happens. If i'm not mistaken you want ## 02 readings at WOT at around .92 but hopefully someone else will confirm that or tell you what it is supposed to be.

 

[1LE]

Yeah it was way rich. Lean it out a good bit and see what happens. If i'm not mistaken you want ## 02 readings at WOT at around .92 but hopefully someone else will confirm that or tell you what it is supposed to be.

You really can't go by that O2 number. Too much inconsistency. At .92 mine is so rich it's blowing big clouds of smoke. It's about right at .84 to .86...

 

[Pure92TSi]

You really can't go by that O2 number. Too much inconsistency. At .92 mine is so rich it's blowing big clouds of smoke. It's about right at .84 to .86...

yeah your right and also i have a 1g and his and yours are 2gs and they vary a little.

Here is a page from Road Race that explains it some:

http://www.roadraceengineering.com/instructions/autotimer.htm

 

[Jimmy Jr.]

Do not tune with the stock narrowband o2. While tuning with widebands on many different cars I've seen the narrowband voltage ranging from .6 - .9 when the wideband reported 11.5 afr.