if this is turbo you could have to much oil in and it gets into the turbo and will run on its own
The ignition system is powered up and ready to run the vehicle.
Bad relay
The old engine sputtered to life as she turned the key in the ignition.
WHY MY ECU 15AMP FUSE BLOWS EVERYTIME I START MY 97 ACURA INTEGRA
Faulty ignition switch.
probably timing or valves. cylinders getting too hot which is igniting fuel that is left after it has been turned off
Its not your engine. Its the fan running to cool the engine down. They all do it and nothing is wrong with your car.
Gasoline engine - spark is cut off when ignition is turned off Diesel engine- fuel is cut off when engine is shut down
Two answers:If it is an old car with a carburetor you could be suffering from a condition called pre-ignition or run on (same thing) the engine will rattle clatter and shake. This is caused by carbon build up. Change the spark plugs, check the mixture, and then try to de-carbon the engineOn a new automobile with injection you have a bad ignition switch or relay.
Besides the smart alec answer "start an automobile", a starter has a small gear, that will both extend as well as rotate when the key is turned. This gear will engage teeth on the flywheel/flexplate, which is bolted to the rear of the crankshaft. As the starter turns, the engine will be turned.
The ignition module will send a signal when the key is turned. If the module is no good the signal is not sent to the other ignition parts,thus not allowing the car to start
check the battery and connections/cables