[Stewhoppy]

Hi,

Thanks for the input, however I have the AFM (active fuel management)tied up out of the exhaust, not the O2 sensors.

Originally Posted by alan91z28

I don't normally post on these forums as i just read this for interest as I focus on 3rd gen F bodies, but i do a lot of engine swaps, engine tuning, etc

I have not worked with the GEN V LT so my statement is only for your general consideration.

You may indeed be running rich, but to know you really need to see a real number such as the actual fuel trim, a wideband o2 reading, etc... you can use a scanner, hp tuners, aftermarket wideband o2 kit etc

Why could you be running rich? Again I am not making a GEN V specific comment, but you state you have the O2 sensors hooked up outside the exhaust (i am assuming you only mean the post CAT sensors and the front exhaust sensors are there). While commonly believed to only be used for diagnostics, the post cat o2 sensors can and are used by some OEM to aid with the fuel trim control. If used this information is combined with the front sensor to give a more accurate situation as the front sensors see a lot of stress over time. Does GM use this on the GEN V i do not know. However you have the sensors hanging out in open air so you can imagine that the information provided to the ECM by these sensors is lean condition so if used by the ECM to modify what the fronts are seeing only it would want to respond by adding fuel

Again, just a general thought and i have not tuned a GEN V, just speaking from other experience