I just repaired this same model with a soda spill. You'd be surprised what gets shorted out in the keyboard. I would replace the top case (trackpad too unless it didn't get damaged) and clean whatever (you didn't specify what was spilled, like coke is corrosive) you can with isopropyl alcohol taking static precautions of course. Definitely dis-assemble to air it out, You can even put the logic in an oven on cookie sheet at it's lowest temp with door open or in a container with a desiccant. No quick or easy way with this model.
Double check all connections just to make sure then put the original front back on and see if you still have the problem. That way it rules out the new part. If it still has the problem there is something you missed in reassembly.
It seems mine collects a lot of dust so I keep a microfiber cloth (think Billy Mays) over the keyboard and when I'm ready to use the Mac I dust everything off and as a bonus, if I wet it a tiny bit I can even clean of my grubby fingerprints. This is also the least expansive of the tips