how to prevent flooding the engine?

breadbin

i had to call out the breakdown the other day after trying to start the engine of a 00 petrol corolla. the lad said it wouldn't start cos the engine was flooded and needed a quick tow to get it going.

it was a fairly cold morning but the car was working perfectly up until then. i told him that i just moved the car out of the drive the previous night and parked on the road and he went 'aahh, there's your problem - engines flooded'.

so what i want to know is how it happened - like is it just because i drove it out onto the road and turned the engine off before it had a chance to heat up or what? thanks

Tea drinker

happens with a lot of different cars, and there's a thread somewhere about similar issues. I can't explain the theory behind it either, I know some VAG people have complined about it. Never happened to me.

Nissan doctor

breadbin wrote: »

i had to call out the breakdown the other day after trying to start the engine of a 00 petrol corolla. the lad said it wouldn't start cos the engine was flooded and needed a quick tow to get it going.

it was a fairly cold morning but the car was working perfectly up until then. i told him that i just moved the car out of the drive the previous night and parked on the road and he went 'aahh, there's your problem - engines flooded'.

so what i want to know is how it happened - like is it just because i drove it out onto the road and turned the engine off before it had a chance to heat up or what? thanks

On older injection systems, lots of extra fuel is injected into the cylinders when the engine is cold so if you start it from cold and then quickly turn it off, such as moving it a short distance like you said, the fuel that has been injected hasn't been burned fully so gets left in the cylinders.

90's Japanese cars are especially prone to it. I did it a couple of times myself without thinking to my old Micra. The only thing you have to do is you need to start it just for a moment is leave it running for maybe a minute to burn the excess fuel.

Thats all assuming that its only happens in those circumstances, if its happens all the time then your looking at perhaps a faulty injector.

breadbin

thanks, yeah it happened before once maybe last year probably in the winter, i vaguely remember just moving the car to the side of the house so its probably just under them circumstances:)

so is it true then if i put my foot on the accelerator and start the engine the car knows the engine is flooded and turns off the fuel injector for a while til it starts? i read somewhere that this was the case but i'm sure the guy who came out would have known that though. might be handy to know in the future but i won't be doing any short trips like that in a while:)

Nissan doctor

breadbin wrote: »

thanks, yeah it happened before once maybe last year probably in the winter, i vaguely remember just moving the car to the side of the house so its probably just under them circumstances:)

so is it true then if i put my foot on the accelerator and start the engine the car knows the engine is flooded and turns off the fuel injector for a while til it starts? i read somewhere that this was the case but i'm sure the guy who came out would have known that though. might be handy to know in the future but i won't be doing any short trips like that in a while:)

On a fuel injected car if you press the accelerator before you start the car nothing happens as the injectors do nothing until the ecu is powered up and the engine is being turned over.

alias no.9

breadbin wrote: »

thanks, yeah it happened before once maybe last year probably in the winter, i vaguely remember just moving the car to the side of the house so its probably just under them circumstances:)

so is it true then if i put my foot on the accelerator and start the engine the car knows the engine is flooded and turns off the fuel injector for a while til it starts? i read somewhere that this was the case but i'm sure the guy who came out would have known that though. might be handy to know in the future but i won't be doing any short trips like that in a while:)

If the engine is flooded, you need to get the unburned fuel to either burn or evaporate and exit the exhaust. With your foot on the floor, i.e. throttle open for maximum airflow, you get maximum evaporation as air passes through the cylinders even if the spark isn't catching. The ECU will limit the amount of fuel injected according to the rpm which will be whatever the starter motor can spin at until the engine fires up. So this is a technique to start a car with electronic fuel injection that is flooded, but it doesn't really matter if you plant your foot before or after starting to turn the starter motor over.

langdang

Would a fly-by-wire throttle over-ride what you were doing with the pedal during start up? ( Also, I guess pressing the pedal when engine is off doesn't move a FBW throttle at all)

breadbin

alias no.9 wrote: »

If the engine is flooded, you need to get the unburned fuel to either burn or evaporate and exit the exhaust. With your foot on the floor, i.e. throttle open for maximum airflow, you get maximum evaporation as air passes through the cylinders even if the spark isn't catching. The ECU will limit the amount of fuel injected according to the rpm which will be whatever the starter motor can spin at until the engine fires up. So this is a technique to start a car with electronic fuel injection that is flooded, but it doesn't really matter if you plant your foot before or after starting to turn the starter motor over.

well i did that for about 10 minutes and the breakdown man did aswell but we didn't get anywhere. it did sort of sound a bit better later on but he reckoned a tow was the only thing for it. he did take one of the spark plug leads off when he was trying to start why was that you think?

alias no.9

breadbin wrote: »

well i did that for about 10 minutes and the breakdown man did aswell but we didn't get anywhere. it did sort of sound a bit better later on but he reckoned a tow was the only thing for it. he did take one of the spark plug leads off when he was trying to start why was that you think?

Just took the leads off and not the plugs out? Bizarre, prevents any chance of burning the fuel and does nothing for vapourisation.
Removing the plugs lets the cylinder breathe directly from atmosphere when turning it over, also allows plugs to dry.

breadbin

alias no.9 wrote: »

Just took the leads off and not the plugs out? Bizarre, prevents any chance of burning the fuel and does nothing for vapourisation.
Removing the plugs lets the cylinder breathe directly from atmosphere when turning it over, also allows plugs to dry.

well i never removed the spark plugs myself but i presume from my last car that they are deep in there and you need a socket and extension to get into where the plug is. all he had was a regular wrench like and he undid the lead and popped it out. was sort of a long rubber thing but it was sparking when he was trying the engine so maybe the plug came out with it?

i really should learn more about how it all works;)

alias no.9

breadbin wrote: »

well i never removed the spark plugs myself but i presume from my last car that they are deep in there and you need a socket and extension to get into where the plug is. all he had was a regular wrench like and he undid the lead and popped it out. was sort of a long rubber thing but it was sparking when he was trying the engine so maybe the plug came out with it?

i really should learn more about how it all works;)

Definitely had the plug out then.