Symptoms
- Cranks a long time without starting after repeated attempts
- Strong gasoline smell from the engine bay or exhaust
- Eventually starts and runs rough for a bit, then smooths out
- May be worse in hot weather
Likely causes
- CommonRepeated failed start attemptsCranking without starting keeps injecting fuel, flooding the cylinders.
- PossibleStuck-open fuel injectorA leaking injector can dump excess fuel into a cylinder even when it shouldn't.
- PossibleWeak spark from worn plugs or coilsFuel accumulates because the spark can't reliably ignite it, and each attempt adds more fuel.
- Less commonCarburetor flooding (older vehicles)A stuck float or over-choking can flood the intake on carbureted engines.
What to do
- Stop cranking and wait 10–15 minutes to let excess fuel evaporate from the cylinders before trying again.
- On fuel-injected cars, try starting with the accelerator pedal held to the floor (check your owner's manual, since this clears flooding on many models by cutting fuel delivery during cranking).
- If it starts but runs rough briefly, let it idle a minute before driving.
- If flooding happens repeatedly, have spark plugs checked for fouling and replaced if needed.
- Have injectors tested if flooding keeps happening even with good plugs and normal starting habits.
- On a carbureted vehicle, have the carburetor inspected and adjusted by someone familiar with it.
Tools and parts
- OBD-II code reader (fuel-injected cars)
Spark plugsSearch: “spark plugs for [year make model]”
When to call a pro
If flooding happens repeatedly rather than as a one-time fluke, have a shop check for a stuck injector or weak ignition components.
Safety
Generally low risk
Generally low risk for a careful person. Stop if anything looks different from what this guide describes.