Replaced oxygen sensor, now car won't start

[88Classic]

OK, quick rundown on what I did...

I replaced the oxygen sensor on the car. The old one was original, and I had heard of good boosts in performance and mileage by changing it. I got a new one from autozone, had the OEM style 1 wire connector on it and everything. I put it in, and drove the car a bit that night. Ran fine. The next afternoon I went to leave for work, and the car fired up, ran for a second normally, then started running really bad almost like it was running on 5 or 6 cylinders, then died out. I haven't been able to get it to fire and run normally since. The only way I can start it is if I floor it then it starts and chuffs out huge amounts of black smoke and stinks like gas like crazy. Still runs like crap till I let off the gas then it conks out. Is this somehow related to the replaced o2 sensor? I'm wondering if one of nylon teeth on the timing gear decided to give up the ghost and I jumped time somehow. It has 133k miles on the original chain and gears.. Also was thinkin maybe its something carb related... It has new plugs/wires/and cap/rotor.

Any ideas? I'd like to get it running again just to putt around until I get around to dropping a 350 Olds in later this summer.

 

[Bonnewagon]

Sounds like a flooding carb. Is there gas around the base or the air horn gasket after it conks out? I don't think the O2 sensor is at fault unless it totally crapped out (unlikely) right after it was installed, BUT the wire may have come off/broken.

 

[88Classic]

When I was fiddling with it I did seem to see a bunch of fuel down in the bowls....not sure how much should be in there normally....I don't have a lot of experience working on carbs. I tried starting it the other day after the car had sat for a week. I cranked it without pumping the gas like I usually have to do in cold weather or if its been sitting awhile. It fired, ran for a few seconds, then conked out again. Back to square one. What could fail on the carb and cause it to flood itself? I did double check the wire on the sensor and its fine.

 

[Bonnewagon]

" it starts and chuffs out huge amounts of black smoke and stinks like gas like crazy. " That's classic flooding. The float is either saturated with gas, but that happens over time, not suddenly. Or the inlet needle/seat is stuck open by a bit of debris. I test by removing the fuel line at the filter, and screwing a short cut-off fuel line with a rubber hose so that I can blow into it. With the fuel bowl full, if you can blow air, the seat's leaking, it should stay shut and not pass any air. If it's dirty, cleaning is indicated.