sometimes we might need to move a cold car, say out of the driveway to unblock your other car. You start your car up, back it out of the driveway and park it by the curb in front of your house and shut it off. You take the other car to work.
The NEXT time...you go to start your curb-parked car...it balks, cranks a long time and maybe doesn't run right when (or if) it starts. It might even show you a "check engine light". What happened, you ask? Well...
When the engine starts up cool-or cold, the fuel injection system allows more and more fuel to enter the engine to overcome the frictional losses in a cold engine and to help it to run better until it warms up. We "seasoned" folk might remember the car term..."choke"?
You started the engine and ran it only for about 1 minute or so, just long enough to move the car before leaving for hours and hours...the excess fuel sitting in and around the combustion intake area can condense back into a liquid and literally "wash" the oil coating from around the piston rings and also fouls the spark plugs. This "gas washing" prevents the cylinder from creating enough compression to ignite the new air/fuel mixture and there you have it. (We really tried for 25 words but it just doesn't work with us that way)
How can I avoid this, you ask? Well easy...let your engine run for 2 or more minutes before shutting it off. You could also move the cars around the night before if you're not too lazy. Don't allow the car to sit in this "flooded" condition for hours and hours.
If it's happening to you right now...put your mobile device down...press the accelerator pedal all the way to the floor...(ALL the way) and crank the engine for no more than 10-15 seconds at a time...This causes the on-board computer to enter "clear-flood" mode and the engine should start right up...might complain a little but will straighten out in a few moments. Try not to over-race the engine when it does start by releasing the gas pedal.
Hope this helps! Might just save you a tow bill too!