Why the engine won't start after going through deep water

How deep was the car in water . are we talking a foot deep with a big splash or three feet or more . was it deep enough to get water into the interior. If the water was deep enough to go into the breather system and get into the engine you could be looking at a hydrolock condition . This is when the cylinder fill with water and it can be bad enough to not allow valves to open or pistons to move and can cause major damage.The damage occurs because you cannot compress water. if this occurs you can try removing spark plugs and cranking the engine by hand at first to move water from the pistons then use the starter to crank it faster to get the water out. Drain the oil if it looks like chocolate milk or if there's more oil than there should be . Then start the process of drying out the electrical components . If you got the computer wet it will only be a mater of time before you have trouble there . even if you are able to dry it out it will corrode and die eventually.

If the water was just a splash and you didn't get more than a little wet you could be looking at drying things out and it will run again . One simple way to dry things out is to spray WD40 on wire connectors on spark plug wires, on the coil and coil packs. WD40 repels water and dries out . Once everything has dried out its a good idea to go around and put dielectric gel on all electrical connections to help repel water in the future and to keep things from corroding since they already are likely starting to since they got wet

Hope this helps