Adam86

iTrader: (10)

I bought a new AEM UEGO Wideband gauge and just got the sensor hooked into the old rear o2 sensor on the driver's side. Even at idle, the thing seems to freak out, reading anywhere from 12.5-15.0. It seems to rarely be in the "green" zone of the gauge but from what I've seen 12-13 seems to be pretty good. What really freaks me out is if I get on it it will go to 17.0+ between shifts (m6) at times and when I let off the throttle. Is this normal? I've been trying to search for info but have come up dry and I am pretty new to wideband gauges as a whole. I understand that AFRs change constantly and I've heard that the UEGOs are good units. The motor was rebuilt about 300 miles ago and my compression is around 9.4:1 naturally aspirated. I figured that with the drop in compression and still being on the bolt-on tune it would be running pretty damn rich through the entire RPM range. I'm thinking that maybe the sensor is too far from the head being at the rear o2 bung.

SSpdDmon

iTrader: (10)

DFCO (fuel cutoff) kicks in during shifts sometimes on M6 cars. I can't remember off the top of my head, but I'm pretty sure it's enabled from the factory on our cars. You should see a swing in AFR's if you're running closed loop. 12.5 might be a little more than normal. Usually, high 13's to mid 15's is about as big of a swing that I see. Using the 2nd bung on the driver's side isn't too bad (as long as you don't still have cats). If you do still have cats, your reading will be skewed slightly.

You might benefit from a retune and maybe a couple of new O2 sensors...not in the sense that it's going to make much more power. But, it might run a little better/smoother.