sorry you're having the issue. If you look on the bottom of the computer, what is the model #? Should start with an A..I can look at the schematic for the board's, but there are many core voltages so I would need to know which one you are wondering about?
Generally with a liquid spill on this model, liquid corrodes where your battery board connects to the logic board. The battery board has a 2nd level board on it which is the sleep switch. The magnet in the display close onto it which is how the machine knows its sleeping. Sounds like the unit thinks it supposed to hardware sleep, and it happens when the OS portion of the booting happens. Also, if the machine believes its sleeping all kb, screen and fan actions will cease.
Does the issue also happen if you perform a software sleep? I attached a link to the part in question. Keep in mind that the part # may be different depending on the specific version of your MLB
MacBook Core 2 Duo Battery Connector Replacement