Flooded Engine

[Ro1]

This morning my IS250 wouldn't start. The engine turned over but it wouldn't catch. This is the first time the car didn't start on the first attempt. I was fairly sure it wasn't a failing Battery because the engine turned over quite strongly and the lights were working well and didn't dim.

After trying this a few times over the space of about 15 mins, I gave up, emailed my apologies for the 9am meeting I knew I wouldn't make and called the AA. The big yellow van arrived within about 40 mins.

No sooner was Mr AA out of the van and he asked me if I had moved the car. I said "No", thinking he was asking if I had tried to roll it. He clarified, looking at my narrow-ish driveway and asked "Did you start it up to move it out of the way of someone else". I remembered then that I had moved it briefly the previous afternoon and not used it since. The engine was probably running for all of 15 seconds. He proudly proclaimed "That's it! It's flooded!"

Now, I didn't think cars flooded since the good old days of my mother, an old Fiat and a choke. (The three of them just didn't seem to work well together!)

Apparently, I'm now well-informed, that an engine can flood if it is left running for less than a few minutes. It was a morning of revelations for me.

Anyway, as Mr AA is explaining to me how to remedy the problem, I'm breathing a sigh of relief and hoping he's right, because I had visions of the car sitting on the back of a flatbed truck, on its way to Mr Lexus, with my credit card taped to the bonnet!

The trick to starting the flooded engine, I readily observed, is to depress the accelerator. This tells the car to stop pumping fuel to the cylinders. Smart, but too-smart for me. I'd never have guessed at that bit of counter-intuitive logic. But, it worked. After three cycles of cranking the engine with the accelerator depressed, presumably burning off the excess petrol in the engine, the car started with the accelerator released.

Has anybody else encountered this problem?

I've read elsewhere that this starting procedure this can damage the cat in some cars - is that possible? Should Mr AA (to whom I was very grateful at the time) have done this? If it's okay, why don't Lexus describe the procedure in the manual?

[dazed]

It's probably a special mode. Remember, modern cars are mostly 'drive by wire' as far as the throttle is concerned. Certainly not recommended on older cars.

Useful to know if that is the case.

[Tango]

It's probably a special mode. Remember, modern cars are mostly 'drive by wire' as far as the throttle is concerned. Certainly not recommended on older cars.

Useful to know if that is the case.

It's an old remedy, and has been a fix for flooded engines since Adam was a lad. My original modified Cooper 'S' (I'm old) had twin 1.5" SU carburettors with chokes and would flood easily if it turned over too many times without firing up.

Full throttle gives maximum air, minimum fuel mixture (as without the engine firing the intake vacuum is minimal), so as it turns over the over rich mixture is weakened until it reaches an optimum mix to fire up.

[jamesholden]

It's quite common on fuel injected cars when there only moved a few yards. Basically, when you start the car a load of fuel is injected, usually more than is required to move the car the few feet your moving it. So the next time you start it, more fuel is squirted in and it floods.

If it does it again, rather than trying to start, letting off, trying again, just keep your foot on the accelerator and keep it cranking, after about 10 seconds it'll have cleared itself, you'll get a nice puff of smoke as the excess fuel is burnt off.

[Steve ( West Mids )]

I've never had a problem with mine, even when I manouvre onto the drive for cleaning / loading up etc. It's starts on the button every time.

[dazed]

It's probably a special mode. Remember, modern cars are mostly 'drive by wire' as far as the throttle is concerned. Certainly not recommended on older cars.

Useful to know if that is the case.

It's an old remedy, and has been a fix for flooded engines since Adam was a lad. My original modified Cooper 'S' (I'm old) had twin 1.5" SU carburettors with chokes and would flood easily if it turned over too many times without firing up.

Full throttle gives maximum air, minimum fuel mixture (as without the engine firing the intake vacuum is minimal), so as it turns over the over rich mixture is weakened until it reaches an optimum mix to fire up.

Cheers. I didn't know that.

[mraines]

Happened once on my previous car, a 15 year old and utterly reliable Toyota Corolla in the exact same circumstances and the fix was the same by the RAC. Live and learn as they say.

Thanks.

[Exiled]

Apparently, I'm now well-informed, that an engine can flood if it is left running for less than a few minutes. It was a morning of revelations for me.

The Telegraph's Honest John has mentioned this on a few occasions. He says you should avoid running the engine for short periods of time if possible, for example getting it out of the garage and switching off. What I try and do now is only get it out of the garage when Im ready for going anywhere.