Failing to start when the car is warm - FLOODING

[427James]

Has anyone else had this?

The car runs fine, but if you stop the car and leave it to go and pay for fuel/ run round Sainsburys etc, and come back to the car when it has cooled a little (say 70c) the damned thing wont start. Feels like its flooded.

If you take off the plugs going to the injectors under the fuel rail, the car starts and runs for a couple of seconds. You can then plug everything back in and start the car without any trouble.

Any explainations gratefully received!

[simonsparrow]

Its not really the weather for it, but you can get fuel vaporisation sometimes. Generally I find if its a really hot day and I park and then try and re-start the car soon after it can occur. opening the bonnet for a few minutes usually fixes it.

But like I say, with these temperatures, that may not be the reason

[427James]

Cheers.

I have a suspicion it may be the temp sender unit issue, although I did change the thing last weekend and the MIL Light has now gone off. I may have to plug the laptop in this weekend to see if the things working.

[mars]

It's customary for the fuel map of Emerald ECUs to contain zeros (no injection) at the highest load site (foot on throttle buried into carpet) and lowest speed site (turning engine over). This enables you to clear the cylinders in the event that you have flooded it.

In practice, foot hard on throttle (until it won't go down any more), hit the starter and let it turn for 5 seconds. That ought to do it.

Not saying this approach has ben applied to all ECUs but it's such a useful idea that I'd find it hard to believe everyone hasn't adopted it.

[jesfirth]

Hi James-my car has done exactly this for the last couple of years but usually only on hot days. It was fine if switched off for a few seconds but almost always failed to start after popping into shop or filling up with fuel etc which takes a couple of minutes. Mine used to take about an hour to cool down and then would start perfectly.

Fuel vapourisation can be a cause but is unlikley at this time of year and also if you have had the car for a while and it has just started to occur it's unlikley to be that.

Mine was caused by a drop in the current to the injectors when the starter motor was spinning so they were not firing when the engine was turning over hence the flooding. It's now been cured but it was a bugger to trace the fault. Get the earths all checked and try putting a meter on the injector cables to see how much power is getting to them. I can't go into more detail because I am not an electrical expert but hope this helps.

If you get stuck you could try just tapping the starter button a few times rather than churning the engine. I believe that as the button is released the power to the injectors increases and it fires up. Usually takes a few tries though.

Jes

[427James]

Thanks for the hints guys, the only strange thing is that if you take the injector plugs off the car will start with whatever fuel is in the cylinders. Once you have cleared the cylinders and reattached all of the plugs, she will fire up first time!

[kojak]

Mines worse when its been stood for an hour or so, and then try to start it. It starts ok...but struggles for a couple of miles. Have to 'heal toe' at junctions.

[ridds]

Whats the fuel consumption like?

Does sound a little like coolant temp sensor failure.

Hot engine turning to fuel it rich for a cold start on key on. Does she smell of fuel too?

[427James]

Yeah, but the temp sender has now been replaced. I will know more when I have plugged the lap top in!