323ti o2 sensor(s)

[kipower]

Hey guys, I have an oxygen sensor question. The car is a 96 TI with a 99 e36 323is motor. Obd2 with m50 manifold, open long tube headers, m3 cams, 96 328 harness and a tuned ms41 DME with ews delete. The car is running. The original harness and ms41.1 was fried so I replaced it. My original harness had conectors for rear o2 sensors only(1 pre and 1 post cat), and the current harness has those plus the two on the injector section for the front o2 sensors. I am running with no o2 sensors and no check engine light(?). The gauge is from the 323 doner car and does seem to be working. The battery light is on because my alt. Is not charging, rpm's are working, so I assume it is functioning correctly. My question is what way should I go about running the o2 sensors? I contacted the guy I bought the computer from and he said it is meant to run off the two pre-cat sensors, but the 323 was not set up for that. Now that I have the 328 harness I could utilize the two connectors for the front, but I worry that he doesn't know 323's ran only of 1 pre-cat and 1 post. He did mention that both after cats have been deleted in the DME but again 323's never had 2 post cat sensors. Last question is why am I not throwing any check engine light? I would just throw 2 sensors in the headers but that's a lot of money if its wrong. I do have the full 323 exhaust laying in the shop with both o2's in them, but only the rear shares the same part number, plus the wires are too short to reach from the headers to the injector rail. Anybody ran into this conundrum?