Crank, crank, crank, and now it smells like a gas station. The engine is flooded with raw fuel that will not ignite. Here is how to clear it right now and what is causing it.
An injector that drips overnight floods one cylinder before you even crank. Strong fuel smell, hard start, rough first 30 seconds. Most common on aging port-injected engines.
Get a full diagnosis →A purge valve that stays open dumps fuel vapor into the intake while the engine is off. The vapor floods the engine. P0441/P0496 codes.
Get a full diagnosis →A bad ECT telling the ECU the engine is freezing cold makes the system dump extra cold-start fuel even when not needed. Flooding within 2 cranks.
Get a full diagnosis →If the spark is weak (bad plugs, dead coil) the engine cranks but cannot ignite the fuel. Fuel pools in the cylinder, you have a flood. Pull a plug, if wet, you have spark issue too.
Get a full diagnosis →Pumping the gas on a fuel-injected car floods it (it only matters on carbureted cars). Modern cars: foot off the pedal, key forward, let the ECU do its job.
Get a full diagnosis →Stuck-open EGR + cold engine = poor combustion, fuel pools without burning. Less common but worth checking with carbon deposits.
Get a full diagnosis →| What You Notice | What It Usually Means |
|---|---|
| Smells like gas, will not catch | Classic flood, clear and diagnose |
| Cranks fine then dies after 1-2 seconds | Bad ECT or cold-start fuel issue |
| Black smoke at exhaust when finally starts | Excessive raw fuel |
| Wet spark plug | Flood + possible spark issue |
| Floods only on cold starts | Leaking injector or bad ECT |
| Floods after sitting for a few hours hot | Leaking injector |
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If your scanner is showing one of these, that's your starting point. Tap any code for full causes and repair costs.
Hold the gas pedal to the floor while cranking for 5-10 seconds. The ECU recognizes this as clear-flood mode and stops injecting fuel. Engine should fire and recover.
Most often a leaking injector dribbling fuel overnight, a stuck purge valve dumping vapor into the intake, or a bad coolant temp sensor telling the ECU to overfuel. Pull codes.
One-time, no. Repeated flooding washes oil off the cylinder walls (causing wear) and damages the catalytic converter from unburned fuel.
Fix the root cause (injector, ECT, purge valve). Do not pump the gas pedal on modern cars. Do not crank for more than 10 seconds at a time without a break.
Flooded: smells like raw gas, wet spark plug. No fuel: dry plug, no gas smell. Two very different problems.
Injector: $200-$700. ECT sensor: $60-$220. Purge valve: $80-$250. Spark/coils: $80-$500. Diagnose by code first.
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