What Is Engine Flooding? How Do You Deal With A Flooded Engine?

Technical

Nov 17th, 2020

What Is Engine Flooding? How Do You Deal With A Flooded Engine?

Even the most experienced and most careful drivers will have to contend with some mechanical mishaps, one of which is a flooded engine.

What is engine flooding or a flooded engine?

Engine flooding occurs when an internal combustion engine is fed an excessively rich air-fuel mixture that cannot be ignited. This is caused by a combination that exceeds the upper explosive limit of the fuel (be it diesel or petrol). Under this condition, the engine will not start until the excessively rich mixture has been cleared.

In simpler terms, the amount of fuel in the engine exceeds that of air. The spark plugs become wet and thus fail to ignite the fuel. As a result, the car fails to turn over or starts briefly then cuts.

How do you know you have a flooded engine? 

You may hear a whirring sound (similar to the noise made by ceiling fans) after ignition, notice a strong smell of gasoline near the exhaust, or experience a hard start.

Your car is more susceptible to engine flooding during colder seasons. The reason is that the engine will need more fuel to warm up during cold weather, unlike during warm days.

How do you prevent engine flooding?

Your car might fail to start if you turn it on and off within short intervals. If you drive the vehicle over a very short distance, allow it to run for a few minutes. Doing so will help warm up the engine. The procedure will also consume the fuel left in the combustion chamber, which in turn prevents flooding.

Moreover, be keen on the amount of fuel you send into the engine; avoid frequent or excessive pressure on the gas pedal.

How do you start a flooded engine?

Although it will take time, it is possible to start a flooded engine.

Before attempting to start the engine, ensure there is enough ventilation in an indoor garage. The procedure will result in a lot of unpleasant smoke.

To get rid of excess fuel, open your vehicle's hood to allow it to evaporate. You can wait for about 20-30 minutes. Next, restart the car without pressing the gas pedal.

If the vehicle fails to start, check the spark plugs. Excessive fuel in the engine can soak the spark plugs, making them incapable of creating sparks that are needed during ignition. If this is the case, clean and dry the plugs, return them then start the car.

Remember to press the gas pedal to the floor; then restart the engine. Avoid pumping the gas pedal.

The procedure will open the throttle, which allows more air into the engine. Once the engine starts, release the gas pedal. Let the engine run for a few minutes to warm up the system.

Note that this option might not work for some modern cars. Instead of a cable linking the throttle to the engine, modern vehicles have electronically-controlled throttle systems.

What will it cost you to fix a flooded engine?

Treating a flooded engine is a DIY procedure unless there are other serious issues with the engine. Fixing this minor hiccup will only cost you time, some effort, and a little fuel.

Can a bad fuel pump cause a flooded engine?

Yes. Although other vehicles will need more pressure, fuel pressure to the carburettor is usually 4 psi to 7 psi. A faulty fuel pump will deliver excess pressure, resulting in lower gas mileage, carburettor damage, and, eventually, engine flooding.

What is the difference between a flooded engine and a flood-damaged engine?

Flood-damaged engines are caused by flooding – yes, flooding as in submerging your car’s engine in deep water. On the other hand, flooded engines are the result of an imbalance between air and fuel in the engine system.

You can fix a flooded engine. Conversely, floods can be very destructive, and the damaged to the engine can be quite extensive. Therefore, a flood-damaged engine might need an expert.

Can a flooded engine be repaired?

Yes. A flooded engine can be repaired. The idea is quite straightforward – it’s all about balancing the amount of fuel and air in the engine. Once this is achieved, the problem is solved.

Can flood-damaged cars be repaired?

It depends on the extent of the damage. It could be just small stains inside the car or a hydro-locked engine. Contrariwise, the damage can also be extensive and cost you more to repair, in which case, you may have to consider replacing the affected part. Get a quote for the cheapest car part using CarPart’s auto part finder. 

Will a flooded engine fix itself?

No. You have to take appropriate measures to restore the fuel and air balance in your car's engine. The good news is that the procedure is simple.

Final thoughts

There are several things that can cause a vehicle to break down. You can fix some mechanical problems, such as a flooded engine, but many car issues need the skills of the pros.  

Apart from the discussed DIY procedures, WD-40 and ether sprays can also work to treat engine flooding. However, you need to apply this procedure with caution because these products are highly flammable. You shouldn't leave your car running or smoke while using either sprays or WD-40.

For parts that need replacing, please don’t hesitate to explore Carpart.com.au. It has a massive listing of used parts; if you don’t find the part there, you can always request us to locate the part for you. 


By Eric Anyega