Confusing problem with internal coolant leak on '93 240sx

[djsilver]

Bought a late '93 240sx (auto, no SCV's, 135k miles) that had "ingested water" in a parking lot flood (got it real cheap!) Owner said it was running rough afterward (no kidding!) I pulled the head & found the #2 exhaust valves much lighter in color than the others but the head and block were both dead flat and pistons are at same level at TDC so I don't think it bent any rods. It had been sitting several months but there was no sign of water/rust in the combustion chambers. I bought new gaskets and put the head back on and did a leak-down check and got reasonable numbers. Hooked everything back up and did a compression check and all were in spec. Fired it up and had unburned fuel coming out the exhaust. Pulled the injector manifold and found #2 injector stuck wide open. Replaced #2 injector and the car runs OK but but it's still burning water somehow. I let it sit running for over an hour to see if it was just burning what was in the exhaust system but no go. I drove down the street and have a big vapor cloud behind me. There's no water/oil mixing and no bubbles in the coolant reservoir. I pulled the injectors, exhaust manifold and plugs and pressurized the coolant system to look for leaks. Let it sit pressurized all afternoon but didn't find coolant in the intake tract, back of the intake valves, combustion chamber or exhaust tract. ?