1998 Buick Regal Manifold leak

Discovered that the upper manifold (plastic plentum) sprung a leak at the ERG input pipe and the water port. Needless to say I had coolant all over the top of the lower manifold. Replace the upper manifold and gasket. Also flushed the antifreeze. My issue, car won't start. I am concerned that possibly the oxygen sensor may have been polluted. The number 6 port got water in it when I opened the upper manifold. I pulled the spark plugs and turn over the engine to make sure that I did not hydralica the engine. I am curious as to weather residual coolant on the oxygen sensor could be the problem. I did verify that all the wiring was correctly replaced and seated properly. Thanks for any suggestion you can offer!