Conversions & Hybrids - 6.0 will not go into closed loop

Hello, I installed a 6.0 with trans onto a "rockcrawler of sorts" jeep for a friend, the engine has a mild cam and it ran very nice. It was replacing a TBI 454 and it delivered great performance, it was all great.
However my friend called me yesterday and told me it wasn't running as good as always, I gave it a quick check and it stays on open loop, with no fuel trim action. I checked the program -using HP Tuners- and it is does not seem to be a programming issue.
I will check it better tomorrow, but what causes the ECM to stay in open loop?
The left bank O2 sensor is reading rich and the right one lean...
Any comments, Ideas?
Thanks a lot
Rat Chevelle

There are several things.
Coolant temp is one IIRC.
It has to see a specific voltage on the sensor for another.
So a bad ground, bad map/maf, etc can keep it from ever getting up to the correct voltage. (rich keeps the voltage low)

I forget what HPT calls it, does it have the correct AFR setting for stoich?
Did he do any work with silicone/RTV? It can kill the sensors.

Now is a good time to tune it in OL LOL so you can get the tables closer.