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bk T
24-09-2012, 10:36 AM
I couldn't start my car this morning! Called AA for help and the guy checked and told me that I have a 'flooded engine'. He got it started by cranking the engine for almost a minute.

What exactly is a 'flooded engine'? Late yesterday afternoon, I moved my car out of the garage to clear out those junks and moved it back. Will this cause a flooded engine? Of my 40+ years of 'car-ownership' I never experienced such thing as a flooded engine!

I've done the 'short' moving the car in and out of the garage countless times but never experienced any 'flooded engine' issue. Is there anything 'not quite right' and needs attention to my car?


Any car mechanics in this forum who can give me some advice?

Cheers

gary67
24-09-2012, 10:46 AM
Flooded is when the engine has too much fuel in the carb and it isn't sparking to burn it

SP8's
24-09-2012, 10:53 AM
What make and model bk ?

Trev
24-09-2012, 10:55 AM
If it has electronic fuel injection this can happen if you move the car a few meters before the engine can warm up don't ask me why. I had a freind who had the same problem a few years ago on a fuel injection car who had to get the AA to start it, and said it was caused by moving the car a few meters before it had time to warm up. Something to do with the electronic sensors and something doesn't shut when you switch the engine off, and petrol just pours into the motor.
SJ if hes around will till you.
:)

bk T
24-09-2012, 11:10 AM
SP8's: It's a Nissan Wingroad 2006 model (Jap import).

Bryan
24-09-2012, 11:16 AM
In olden times you use to floor the accelarator and keep it there. Then turn on the key and let it crank over until the motor fired. Sometimes we use to pull out the choke as well but can't remember the reason other than cutting out air to the mixture.

Bobh
24-09-2012, 11:26 AM
I used to flood my old Ford Econovan quite often on a frosty morning. If I kept turning it over it just flattened the battery. I quite often went inside and had a cup of tea or something. When I came back and tried again it usually started first time. Swearing at it did not help.

prefect
24-09-2012, 11:41 AM
With fuel injection its not your fault the car flooded. All you can do is try different amounts of gas pedal on a cold start. It might well be another fault that is causing the engine to not start and run straight away.

Trev
24-09-2012, 12:39 PM
And another thing you should never do on a FI car when doing a cold start is touching the accelerator as this can also flood the engine and make it hard too start.
:)

The Error Guy
24-09-2012, 02:16 PM
Flooded cars no, mowers yes. Too much fuel in the engine, basically makes the mixture to rich for the fuel/air to go bang. On smaller engines like mowers/saws etc or older cars you can just cycle the engine a bit with the fuel pump off/throttle closed or just let it sit. If it's really flooded (like what happens with our old pump engine) you can remove the spark plug to let the cylinder ventilate.

kahawai chaser
24-09-2012, 07:14 PM
How did the AA determine it was flooded? Any visual inspections or by engine sound? or diagnostics? Because it's a 2006, i.e. relatively new, would not expect any faulty components. I think I had similar flood start symptoms with a weak fuel pump. Another time was a dying cam angle sensor.

Maybe a leaky fuel injector, faulty fuel regulator, or faulty/disconnected temp sensor triggering a excess of fuel. Once I had a hidden disconnected wire on my Nissan to the engine temp sensor, which required a restart, due to the car conking out after a warm drive, after being parked briefly (engine off) and then attempting to drive again. But always started cold.

The Error Guy
24-09-2012, 08:43 PM
Could be that actually, my car has a sticky thermostat meaning the lower radiator hose stays cool/cold. The result is the Auto choke sensor thinks the engine is cold, when trying to up the RPM's the engine will nearly stall going from 1000-2000 RPM. A Quick high rev frees it up. Doesn't happen often.

Trev
24-09-2012, 09:32 PM
How did the AA determine it was flooded? Any visual inspections or by engine sound? or diagnostics? Because it's a 2006, i.e. relatively new, would not expect any faulty components. I think I had similar flood start symptoms with a weak fuel pump. Another time was a dying cam angle sensor.

Maybe a leaky fuel injector, faulty fuel regulator, or faulty/disconnected temp sensor triggering a excess of fuel. Once I had a hidden disconnected wire on my Nissan to the engine temp sensor, which required a restart, due to the car conking out after a warm drive, after being parked briefly (engine off) and then attempting to drive again. But always started cold.

What happens when the engine is started from cold and only runs for a minute or two it doesn't burn all the fuel that is injected into the motor which is determined by the electronic sensors, so when you go and try and start the engine again later when the engine is still cold the injectors squirt more fuel into the engine, which is added to the fuel which is already there, hence you end up with a flooded engine.
:)

lakewoodlady
24-09-2012, 10:59 PM
Yep, happened to me once, outside supermarket. Called AA and felt very embarrassed when told it was flooded. Previously it had been idling too fast and then "running on" when turning engine off. (pre - ignition?) Sticky butterfly in the carburettor, I was told.

LL

coldfront
25-09-2012, 01:14 AM
Funny mate and I were talking about this type of thing today after hearing about the snowcat driver who got his wires crossed on a battery on a NI ski area. Anyways mate was telling me about an incident years ago someone he knew blew up and engine after flooding it! Flooding as in there was so much fuel in the engine when it was turned over the spark literally tore the insides of the engine apart. They wandered why one of the spak plugs was bent...lol.

Never mind the sparkplugs most the valves and gaskets were shot all because they flooded the engine.

For me the worse I have had from a flooded engine is a backfire that blew apart a silencer.

Winston001
25-09-2012, 01:42 AM
"Flood" means the combustion chamber becomes wet with fuel, including the sparkplug. Essentially there is too much petrol and not enough air for an explosion (burn) to take place. So far as I know the remedy is to turn the motor over with no accelerator or choke so as to suck clean air through the chamber. Once it has dried a spark should be possible.

prefect
25-09-2012, 09:35 AM
Funny mate and I were talking about this type of thing today after hearing about the snowcat driver who got his wires crossed on a battery on a NI ski area. Anyways mate was telling me about an incident years ago someone he knew blew up and engine after flooding it! Flooding as in there was so much fuel in the engine when it was turned over the spark literally tore the insides of the engine apart. They wandered why one of the spak plugs was bent...lol.

Never mind the sparkplugs most the valves and gaskets were shot all because they flooded the engine.



Sounds like BS to me.

SurferJoe46
25-09-2012, 10:37 AM
OK --- a fuel injected engine is not supposed to ever become flooded because there is never a pool of fuel anywhere in the system to collect enough to flood it.

Each cylinder on modern engines gets it's individual fuel allowance for itself, and it is not pooled with any other cylinder. The old centralized THROTTLE BODY fuel injection systems COULD give some grief if they had post-run leaks, and they could allow some fuel to flow past the injector head(s) into the throttle body resulting in what is perceived as a typical 'flooded engine'.

That's a misnomer though.

Modern fuel injection systems aren't built like that any more - but they might still be unloading some archaic engines and fuel systems n'stuff on Upsidedown Land.

Yet.

REAL 'Flooding' was a problem with an old carburated engines where the carb actually held a small amount of fuel inside it's float bowl - much like your toilet tank - and it was capable of dribbling into the intake under certain situations.

The real problem was almost always that the choke on those carburetors would stick or it needed adjustment seasonally to keep it from being 'ON' too forcefully and it would block the air from atomizing the fuel and entraining it, flowing with the air into the individual cylinders for combustion. The excess fuel in those situations would create a lot of black smoke (unburned fuel) and possibly wet the spark plugs sufficiently to keep them from sparking the fuel in the cylinders.

Fords with two- or four- barrel Holley or Autoilite carbs had a bad habit of smacking the choke closed when the engine backfired. When they got towed in, we called it a BPR (Ballpoint Pen Repair) since we'd just jam a ballpoint pen down the throat of the carb and crank the snot outta the engine and it would eventually start and run.

Fast forward to an injected engine ----------------------------->

Fuel injectors are not supposed to dribble or leak fuel after the engine is stopped --- even if it stalls. Once the distributor reference signal is lost, the ECM ceases allowing fuel to pass through into the cylinders and all fuel injection and in most cases the fuel pump too - will stop.

The ECM requires a 'GREEN BOARD' to allow fuel to be sprayed into the engine:::


1 - TACH signal from the distributor that tells the ECM that the engine has spark and is, indeed at least rotating.
2 - SOME vehicles also require a clean DC output from the alternator as a qualifier too.
3 - A 'cranking signal' from the cam position sensor and/or the crank position sensor too, if it has both/either of those sensors.
4 - Once the 'RUN' signal is in effect, the 'CRANKING' signal is ignored.
5 - ALL devices and sensors are supposed to be answering the ECM with one of two status reports:::

a. Oxygen sensor(s) in place and at least electrically capable, even if not 'talking' correctly.
b. Coolant sensors, airflow sensors or BMAP or MAF are at LEAST talking to the ECM, good or bad data is acceptable.
c. Distributor 'TACH' signal is steady and RPM is in a 'logical' range for the position of the Throttle Position and the air flow sensor (MAF/BMAP/Ionization Sensor/ and a few others, particular to each separate manufacturer.

IF there's bad data, then the ECM has pre-programmed responses to that situation:
1. it will light up the Check Engine light or
2. the more dreadful "CHECK ENGINE SOON"
3. AND THE VERY WORST LIGHT: A blinking CEL!
4. It MAY shut off the engine if it is so programmed that way (think: BMW, Rolls and maybe Porsche)

#3 means you are damaging expensive parts and should stop running the engine immediately!


It's not as complicated as it sounds and it all takes place rather invisibly under the hood and the dashboard.

Here's what to do IF one suspects a FI'd engine is flooded (not very likely, but it can happen):::

Hold the throttle in the WOT position - that's WIDE OPEN THROTTLE position - and attempt to start the engine with the throttle to the floor.

This WOT mode turns off the fuel injectors and IF the engine is truly flooded, it will clear the cylinders out of any excess fuel.

If it really REALLY ALMOST starts, then indeed there was fuel in where it shouldn't be and got there from some bad control or leak in the pressure side of the injection system/injector(s)

But again I say: FI'd engines are NOT supposed to flood ------------ nor stall.

coldfront
25-09-2012, 09:41 PM
Sounds like BS to me.

Which part?

prefect
25-09-2012, 09:54 PM
Which part?\the spark literally tore the insides of the engine apart.

The Error Guy
25-09-2012, 10:56 PM
With regards to coldfront's story the only thing that might have happened there is a bit too much fuel got into the cylinder (by a bit I mean a lot) and the force of the rotating engine bent the con rod since the fuel wouldn't compress as air would.

Destruction could have happened if the engine flooded a cylinder tsunami style, engine was cranked and fired, as the flooded cylinder began it's compression stroke the conrod buckled, piston head/crank damage may have occurred at this point also. As this mess of twisted metal was thrashed around in the engine a lot could have happened. The un balanced crank could have ripped apart bringing the other pistons with it or the fuel and oil could have caught fire in the sump.

So total engine destuction is possible I believe however a simple bent conrod is more likely, the boys have been spinning yarns with ya cold front, nothing like a "it could have been THIS BAD!!! to cheer you up :D