In the old days this was carbon build up in the cylinders. I don`t know if this is still the case with modern engines.
Carbon builds up and gets extremley hot, so giving an ignition point for petrol fumes even though the spark plugs are not sparking. The engine stutters on until the fumes are too weak to ignite.
Ideally you should take off the head and clean it all up but thats a big job. Alternatively, buy a bucket of redex and follow the instructions for cleaning the engine (pouring it down the plug-holes). It makes an enourmous ( ) cloud of smoke when you start up but alledgedly does some good.
How it got to that state in the first place is also a good question. Maybe the temp sensor is gone and you have been runnig rich for ages? Check your exhaust for lots of black fluff.
The father of one of my friends has a Citroen Xantia that works even without the key, I mean, you turn it on and you can take the key out that it will continue to run and not for 20s but for the all day if necessary!!!
I'd go along with Mr Throttleman
In the old days cars not tuned correctly for the new fangled fuel would indeed run on, but what with knock sensors and the like your engine should be fine.
Time for a service though?
Thanks Chris - I've added Redex to the shopping list along with polish and t-cut (yes, tomorrow is going to be car day.... )
T-cut on a "Metallic" finish ??? (not sure what paint you have )
Even on a Plain, unlacquered car, the "worst" I would use is Meguiars Fine cut cleaner unless I has some really serious problems.
Would normally wash, clay bar to remove all the surface Cr@p , then use paint cleaner if nessecary, then "Wax"
Ok guys, you have it all wrong; a car with electronic injection canít run when the ignition key is off. For the engine to run we need two things; fuel and something to ignite it. Carbon residue can ignite the fuel, but once you turn
of the ignition the injectors won't inject any more fuel, so basically it's impossible. Since your car occasionally keeps on running Lips, I think either a relay is stuck or there's a short in the ignition switch. ( Hugo is right )
Concerning pouring something down the plug holes; don't If you pour to much fluid down there the piston cant go all the way up, and you might risk a bent connecting rod or damaged bearings. If you want to clean the engine internally use some new fandangly fuel or get a fuel additive from STP or Redex.
Concerning pouring something down the plug holes; don't If you pour to much fluid down there the piston cant go all the way up, and you might risk a bent connecting rod or damaged bearings.
I`m happy enough to be wrong, my mechanical knowledge is more in the carb times than these new fangled injector thingies However, don`t dismiss the fun factor of redex, it can smoke out an entire suburban street with smoke after you have cleaned the engine. Great fun for annoying the neighbours and impressing small children (or chav car drivers, which is often the same thing)
As far as putting the fluid in the chamber is concerned, you don`t actually put the plugs back in until you have turned the engine to get rid of the fluid first (the instructions are very clear on the bottle) because that woudl obviously be stupid. Its more of a soak to get rid of the crap in there and it makes your car go immensly fast for about 10 miles (then its back to normal again )
Hmm, I may go get a new bottle as the neighbours are annoying me this morning
Sorry Chris, didn't mean to dis you As an old Carb'ster you surely must know the mineral water cure then. Same fun factor as the redex stuff; remove the filter housing, start the car, keep the revs steady at 3000 rpms while slowly pouring at least one litre of Mineral water down the carb. The entire neighborhood will be covered in steam in less than one minute It's a cheap cure and it works wonders
Oh no diss was ever taken I assure you but thanks anyway
Nope, can`t say I`d heard of the mineral water one (does that clean the carbon? cool!) but it sounds cheaper than redex Now, how to do it through those twin dellorto's when they are mounted horizontally? Tricky
Well, I did buy some Redex fuel additive, and I'm going to put it in later when I go to fill up. Curiously enough, the problem hasn't recurred since yesterday afternoon. Is there any way possible that this could be connected to temperature? Both times it happened, it was really really hot outside - is that just a co-incidence???
As you say Fraser, the car is still under warranty, so I don't want to be tinkering about too much myself. My service isn't due for another 2k miles, but if the problem keeps recurring, then I'll take it in to AR for investigation.