What can fuel flooding of an engine cause?

Updated July 19, 2017

Vehicle engines must have an appropriate amount of air and fuel to run. An engine flooded with too much fuel will not start normally. Cars with carburettor engines commonly flood with fuel, but it can also occur on vehicles with fuel injection systems.


An engine flooded with fuel will cause the vehicle to smell of gas. The engine will crank but not start, and may sputter. Black smoke may come out of the tailpipe once the vehicle is started.


One cause of fuel flooding is pumping the accelerator while starting the engine. Pumping the pedal creates excess gas in the engine that can soak the spark plugs. Wet spark plugs cannot generate adequate voltage to form a spark, which prevents ignition. Another cause is dirty fuel injectors, since they can remain open and allow too much fuel into the engine.


Let the vehicle to sit 15 to 20 minutes with the hood open to allow the excess fuel to evaporate. Next, try starting the vehicle again and do not pump the accelerator. Removing the spark plugs will allow them to dry faster. Perform regular vehicle maintenance on the fuel system to keep it clean.

Cite this Article A tool to create a citation to reference this article Cite this Article

About the Author

Nicole Hamilton has been a content writer since 2005. She uses her journalistic style to create informative articles for websites such as Hamilton earned an Associate of Science in multimedia design from Okaloosa-Walton Community College in Florida.