SpoolinEK9

OK well i just got finished hooking everything back up puttin oil in it blah blah blah... so i have shitty battery and i charged it and my car started then died tryied it again gave it about 5% throttle and it started and was staying on then i turned it off and now it wont start anymore. im getting code 41 which is the heated 02 sensor code but this should not stop it from start this is the only code i am getting and my car isnt starting. i have a new battery, getting spark, motor is cranking, getting fuel but just wont fire up. when i try and start it it just makes the noise, baa baaa baaa like it wants to fire up but wont. i have checked all the major sensors and everything is in place. just for backround i have a 99 civic hatchback with a 94 ls motor and obd2b to obd1 jumber harness, and currently have it running open header with no o2 hooked up but this should not stop it from starting. the part that doesnt make sense it that it started early and ran for about 2 or 3 minutes and now wont start again and when it was running it was rich of course but for the most part smooth but loud because its open header, please help me lol and if you live in the seattle area and you know your **** and could seriously help me out and get this thing started i would give you some cash.