Anyone care to comment on these readings? I made some dyno runs a couple days ago and my numbers were lower than expected. The first two pulls the 02s were steady around .920 to .940 from 5000 rpm all the way to 6900 rpm. But then on the last three pulls instead of staying at a steady reading they were increasing with the RPM all the way up to above 1.0. However, the AFR was pretty much steady at 12.9. Timing was 30.5 across the board.

For example:
RPM......O2
5400....0.910
5600....0.920
5800....0.930
5900....0.940
6000....0.950
6100....0.955
6200....0.960
6300....0.970
6400....0.980
6500....0.990
6600....1.000
6700....1.010
6800....1.020

Anyone?

 

Why do you call those readings “crazy”? They correctly indicate that your AFR is rich. My guess is that the difference from earlier observations is due to higher temperatures.

 

My AFR was not rich. As I stated above, AFR was 12.9 from 5000 rpm all the way to 6900 rpm. The O2's should have read a fairly constant number but they did not. Just at the drag strip last Friday the O2's were back to reading constant numbers across the entire RPM range. So I'm not sure why they were acting so weird on those couple dyno pulls.

 

That is why narrow bands are teh suck

 

get a wideband or hook up your own oxygen sensor into your exhaust and do searches to see how to hook everything up. My plans are putting an oxygen sensor in the rear driver side of my Y-pipe (since i have no cats, and i have 02 sims on the rear oxygen sensor connectors) and use an Autometer gauge to measure about where my air to fuel is. I'm going to borrow a friends wideband that has already been tested to see if my gauge is calibrated right.