# The Right Way To Clear a Flooded Fuel Injected Engine?



## MichaelZ

My son flooded our 99 Buick LeSabre in the cold morning two days ago. I tried "clearing" the gas, but I only made the plugs wetter. I know this cause I had the front 3 plugs out, dried them off, and then tried to start, flooring the gas. But I apparently did not do this right since when I removed the plugs again they had a lot of gas on them. So later in the day I took ALL the plugs out, which is not easy on this car since you must remove a support bar and the back plugs are not easy to get at. An hour with the plugs out, and put it back together and it started. Perhaps it was just REALLY flooded. 

But here is my question: Should I 

Press the gas pedal to the floor as I am turning the motor over?
Press the gas pedal to the floor just before I turn the motor over?
Press the gas down right after I turn the motor?

And btw, the owner's manual recommends this procedure to clear a flooded engine, so it is supposed to work. They do not specify the exact timing of when to floor the gas pedal.


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## Roadking

With a carb and electric fuel pump, it's to the floor as you turn on the ignition/fuel pump.
Injection...I pull the plugs, hit them with a match, and reinstall when all 8 are done. Often, I put the plugs back in the wires and set them on the holes and crank it...get some neat flames (gets excess fuel out of the cylinder). FWIW.

Matt


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## farmerj

In an old carb engine, you'd floor the pedal and open the throttle plates AND the choke plate. The idea being you want as much air and as little fuel as possible to clear the extra fuel

In a fuel injected car, the pedal to the floor is telling the computer it's flooded, don't inject any fuel. Manuals refer to that as WOT or wide open throttle. It also opens the throttle body butterfly all the way too.

So BEFORE you start cranking, floor the pedal and don't move it till the car starts.


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## Guest

I've never flooded a fuel injected engine . I would think something would have to be malfunctioning for one to flood .


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## farmerj

WV Hillbilly said:


> I've never flooded a fuel injected engine . I would think something would have to be malfunctioning for one to flood .


Either something is wrong mechanically or you forgot the golden rule. Partly push down on the accelerator.


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## Guest

farmerj said:


> Either something is wrong mechanically or you forgot the golden rule. Partly push down on the accelerator.


On my fuel injected vehicle engines I think the computer is supposed to control the throttle position under starting conditions . I never touch the gas pedal when starting the engine . On older tractors & such that didn't have a computer controlling everything I can see where it might be necessary to manually position the throttle .
I'm just stating my own observations & thoughts & that most certainly doesn't make my assumptions correct .


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## joejeep92

Wide open throttle is known as clear flood mode atleast until drive by wire systems were introduced. Hold your foot to the floor and crank.


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## topofmountain

Holding the throttle does nothing on a computer controlled engine except open the throttle body butterflies. Gas is controlled TPS which is electronic. If it is flooded then you have a problem. Like maybe a FPR or leaky injectors.


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## farmerj

Tps. Stands for throttle position sensor. It tells the computer how much the person is pressing on the foot feed.

Idle is controlled by an IAC or idle air control. Its a liniear motor that drives a plunger opening or closing to lean or richen the mixture based on fuel curves programmed for the conditions.

Temp, map or bark sensors come into play then to tell the ecm current loads or demands.

These are used be the ecm to determine dwell time of the injectors which controls the amount of fuel used by the computer.

Bosch developed the original fuel injection system some 40+ years ago and not much has changed in the system since then.


As to the op,

Pu your foot to the floor before you crank it. 15 people will come up with 15 titles for it. The process is the same.

The next 5 pages will now be to debate the benefits of sfi vs mpfi vs tbi


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## davel745

I heat the plugs with a propane torch and get them hot put them back in and the car will start even if the plugs are cold. maybe do the two easiest ones and try it if it catches it will clear the others


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## MichaelZ

Thanks all. Farmerj and joejeep92 answered my question. Press and hold gas just before turning key to clear out a flooded engine . But for normal starting do not touch the gas at all. What I think happened was my son thought the car was running and then he pressed the gas just as it quit. 

To others that wondered why it flooded at all. The car was at -20F - a_ lot_ of things do not work right in a car at those temps


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## farmerj

Amazing what -20Â°f temps will give you fits of.


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## HuskyBoris

MichaelZ said:


> Thanks all. Farmerj and joejeep92 answered my question. Press and hold gas just before turning key to clear out a flooded engine . But for normal starting do not touch the gas at all. What I think happened was my son thought the car was running and then he pressed the gas just as it quit.
> 
> To others that wondered why it flooded at all. The car was at -20F - a_ lot_ of things do not work right in a car at those temps


it was minus 22 here monday morning and my Impala (same as your Lesabre) was choking,spitting,stuttering and just not liking it much,,after about 5 to 10 seconds it cleared up,,I think because it was so cold it dumped a buttload of fuel into the cylinders faster than my old sparkplugs could burn it off ig:


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## dodgewc

pedal wide open throttle then crank engine
check fuel pressure regulator, remove vacuum line and see if fuel present


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