Whats the best thing to do, leave the engine running or turn it off. I saw the following on the web (US based) and wondered what backroomers thought. I run a TDCI mondeo, is it best to leave it running or switch off?
www.slate.com/id/2192187/
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I can only speak from the point of view of a lorry but the advice in the last couple of years fron SAFED has been to switch the engine off and not let it idle at all.
With the introduction of vehicle trackers, it's not uncommon to find the office is monitoring idling, and a phone call to the cab will ensue to enquire as to why the engine is idling.
On a sizeable fleet there is apparently a considerable saving on fuel to be made.
Pat
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I was brung up with the approach that diesels, especially turbo-charged ones, need to be run above 35% power to prevent foulling from poor combustion. As this is not always possible, the Italian Tune-up is often necessary to maintain combustion efficiency
A local major bus company has recently issued instructions to its drivers that engines are to be stopped if the bus is likely to be stationary for more than 3 minutes.
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>> A local major bus company has recently issued instructions to its drivers that engines are to be stopped if the bus is likely to be stationary for more than 3 minutes.
In London, that would mean switching off at every bus stop! Not only would this wear out the starter motors, but would probably flatten the battery too - I was always told that it took 10 minutes driving to replenish a 3 second starter use on a diesel
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>> >>- I was always told that it took 10 minutes driving to replenish a 3 second starter use on a diesel
I think on older diesels this would be correct but on modern common rail systems perhaps this is not the case.
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Here on the railways out trains are not to be switched off they idle on there own for 15 mins with no key in then shut down with a timer, now it's switch off due to fuel prices the enviroment issue is not the reason.
As for your car in a traffic jam if you have been sat there for 15 mins and looks bad yes turn off but otherwise whats the point.
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A key point in the article is that modern fuel injection systems are so parsimonious with fuel when starting and idling, that any saving made by switching off for a SHORT stop (i.e. less than a couple of minutes) is going to be tiny.
For longer hold-ups (5 minutes plus) I personally don't like leaving the motor ticking over for that long.
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Does it matter how long you keep your TV, boiler etc. running?
Same goes to car engine. It's your car, your money - so burn as long as you wish ;)
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BMW, with their stop/start system, say it's worth turing off the engine if it's going to be stopped for 2 seconds.
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Dont Audi have a cunning arrangment where the pistons stop at the optimium point for easy restarting? on their cars equipped with stop/start systems?
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What is the optimum point for restarting ? Whether they have this system or not: id love to know the answer to the question!
Its a bit like the chicken and the egg if you think about it!
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I've currently got use of a Citroen C3 with a stop/start system and it does my head in. Everytime you pull up and stop, so does the engine. I think that I've stalled the engine - which is impossible to do as it's got a semi automatic gearbox. I've now found the relevant button on the dash to disable it. Trouble is, it defaults back to enabling the system when you next start the car. It does seem a very efficient system though. The engine fires back up with no noise heard from the starter motor and within milliseconds of releasing the brake pedal.
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anybody who has ever kicked over a large cube motorbike with one cylinder and no decompression switch knows the optimum point for the piston for this
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Fond memories...
www.4strokes.com/guests/uploadpics/1980HondaXL500....g
Better to bump-start it than risk kneecapping yourself.
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anybody who has ever kicked over a large cube motorbike with one cylinder and no decompression switch knows the optimum point for the piston for this
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And also to wear a shin-pad in case the ignition timing isnt set quite right and it kicks back !!
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I think one would need to now how much fuel the ECU chucks into the engine to start it up, and that would depend on all manner of things, engine temperature and ambient temperature for a start.
My 58 reg tractor tells me how much fuel it is burning. When cold the 6.6 litre engine normally shows about 2.5 litres/hr and nearer to 2.2 litres when hot. Considering it uses 32 litres/ hr under full load, any saving will soon be lost when in work.
I'm not sure what my old 1.4 litre car uses at idle, but I'll guess hardly anything. It was once sat in traffic for an hour and still averaged over 42mpg for the days journey.
Excessive idling can lead to glazed bores, mine normally gets switched off because of this and that I don;t like giving Gordon Brown any more money than is strictly necessary.
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i idle lots of cars if they needed a full valet and its cold out,sometimes for 4 hours if they turned out dirtier than at first looked (easy on modern stuff ) all i can say is they use minute amounts of fuel but i do remember as a lad on the local hill looking at the stars with the latest girlfriend and you could see the fuel guage going down as the carb trickled the jungle juice in ,so we turned the engine s off and cuddled up closer (did i mention a mate creeping up on us with no lights on once then turning them all on and blowing the horn? ive still got a bump on the back of my head)
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Modern hi-tech stop/start systems might be ok, but having taken the skin off my knuckles with two starter replacemments on the Mondeo I've had for six years I think I will suffer the odd few quid per annum by leaving the engine idle for two or three minutes at a time.
I'm getting too old for laying on my back in the rain trying to undo a stubborn bolt that I can't even see.
Edited by Robin Reliant on 29/12/2009 at 16:59
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i idle lots of cars if they needed a full valet and its cold out sometimes for 4 hours if they turned out dirtier than at first looked
Something I've never heard before, but read the other day from a mechanic strongly asserting that you shouldn't let a car idle for long periods as the lower oil pressure can mean that top-end isn't being lubricated properly.
No idea if there's any truth in this in a modern car, but wonder if hydralic tappets and OHC's might be affected?
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so we turned the engine off and cuddled up closer (did i mention a mate creeping up on us with no lights on once then turning them all on and blowing the horn? ive still got a bump on the back of my head)
BB - You seen the film "World According to Garp" dating from the days when Robin Williams was funny?
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I leave mine idling if I want an orange. One of the few snack foodstuffs it is more or less impossible to eat cleanly while driving.
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Don't let Paul hear you say that Humph:)
Pat
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Nuts are much easier to deal with. Though they can make you dry.
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But at least an apple core is biodegradable, and you can make false teeth out of orange peel to frighten parking wardens.
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no bagpuss but have logged it to favourites,maybe buy it in the new year when ive paid this months card off :-)
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I dont think this is a complex issue,
If you sitting in traffic for more than 5 mins and it doesn't seem to be moving turn off.
I'm more interested in idling on turbo cars. Especially after m-way driving or hill driving. Regardless of the advances in oil technology i always idling my car for 15 sec's... more if i've just come off the motorway or going up steep hills.
I'm not a fan of stop start at all. It seems like a silly marketing tactic to get the co2 emissions down and the MPG up to appeal to businesses and even private buyers in this absurd "green" way of thinking.
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Thirty or forty years ago I remember reading that in the real frozen far North*, the necessarily large vehicles, if left out of doors, were left idling all the time when not being driven. It was the cheapest way to keep them going. If you turned them off for a couple of hours it was the devil's own job to thaw out the fuel lines and get them started again.
I wonder if it's still like that?
*Finland, Northern Canada, places like that. I don't mean Aberdeen or the Orkneys.
Edited by Lud on 03/01/2010 at 22:51
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On a similar note, i read a few stories of motorists being fined by police for letting their cars idle on their own drive ways.
Its against the law
Tut.
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What law states that? A driveway is private property
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I wonder if it's still like that?
The last time I was in Canada in winter, (skiing), the cars parked away from a mains power supply for their block or sump heaters had a thermostatically controlled start stop system. Disconcerting when a car starts itself until you get used to it!
Edited by Old Navy on 04/01/2010 at 09:27
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"the days when Robin Williams was funny"
I'm not sure he's that old, BP...
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Two comments
(i) In der Galaxy I was intreigued at how much higher I could push the mpg figures from the trip computer ( which was/is accurate), IF I stopped the engine at traffic lights etc.
this in generally mixed semi rural driving.
Plus a mate with a borrowed Scania artic was looking for the "miles to fuel" when he happened across the %age fuel consumed when idling figure
=20%
=gulp
as far as I am aware this truck was doing food deliveries to supermarkets
cheers
M
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The trip computer in our Zafira 2.2 petrol shows around 0.3 gallons per hour when idling, once the engine is warm and air-con is turned on.
To put that in perspective, on a full tank it could sit there and idle for 32 hours before running out of fuel.
In that case, 10-15mins idling seems like nothing, fuel wise.
As to wear and tear, I've no idea.
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Local authorities have the power to fine car drivers £20 or so on the spot whose engine is idling. Its all in the name of so called 'green' issues although one can almost guarantee none of that revenue raised will go towards planting trees or producing informative and educational leaflets.
However I've read that unless stationary for more than a minute, its not worth switching off because the cat will not reach its optimum operating temperature and therefore be less efficient plus the initial burst of fuel used to fire the engine up will cause more CO2.
Unfortunately the technical facts won't stop local authority nazi's slapping an on-the-spot fine on you whilst you sit going nowhere in a jam.
Traffic lights showing a count down until they turn green would be beneficial so at least we as individuals could decide whether we switch off or not.
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A neighbour startes his 4x4 up every morning for the past 2 weeks while it's been -c leaves it idling for some 10-15 mins it's a diesel belching out blue smoke, im sure this is no good to the car im not interested in the enviroment plenty of bigger machines pollout more than a car.
Told him fit a auxillary heater nice bit of kit for these very cold mornings!
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On the TV series Ice Road Truckers the trucks had their engines running continuosly for the full three month season, only being switched off for oil changes.
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On the TV series Ice Road Truckers the trucks had their engines running continuosly for the full three month season only being switched off for oil changes.
That is because they are a nightmare to start again when it is that cold. Fine if you can get them near power and plug the transmission, block and sum heaters in and have a charger/starter to hand.
Those trucks will probably have a setting on the cruise control that allows them to set the low idle a little higher to keep the engine nearer to operating temperature.
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I think its better to leave it running as long as its not more than about 3-4 mins, then I would tiurn off.
In the winter mornings I have been starting my car and leaving it to run for about 10 mins, it helps to clear the windows, and I do clear them ALL of snow ice etc even with heated winscreens you still have to clean the side windows. Also gets the heater going that bit sooner when I am in it.
Rather use a little fuel than have a stupid accident.
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snip - can't be bothered editing out the swearing and replacing with pfd
Edited by Dynamic Dave on 16/01/2010 at 14:14
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January 08 in Scotland a law was passed that bans exessive idling. This is for polution reasons, taxi ranks, busses, laid up lorries etc. Regards Peter
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What chance does he have from a legal standpoint?
Keep a detailed log of the noise nuisance & speak to your local environmental health officer.
Ask/get neighbours opinions - maybe one or two will also complain to EHO - can be a longish process, but the sooner you start the better. Also consider taking video footage - may seem extreme, but it's good evidence of ongoing anti-social behaviour & nuisance.
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My brother bought an Audi 80 1.8 petrol in the mid 80s from an auction, it used to stall a lot, then we found by by accident if you touched the throttle the starter turned over and the car restarted - even in gear! I looked at the wiring and found various strange solenoids and determined the car was SUPPOSED to do this, there was a 555 timer circuit running off a speed sensor which cut the engine after a few seconds when the car was stationary. All the wiring looked factory fit - I reckon it was an Audi development/test hack that escaped the crusher and into the second hand-market. Can't remember what he sold it for - probably should have kept it.
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In the winter mornings I have been starting my car and leaving it to run for about 10 mins
Doing that results in more engine wear. To minimise engine wear drive off as soon as you've started the engine. www.consumerenergycenter.org/myths/idling.html
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As I posted in another thread, obviously the bore wash thing doesn't apply to diesels.
Leaving a cold petrol engine idling is the worst thing you can do, it will stay colder longer meaning the engine will be running ?on choke? (cold-start fuel enrichment) longer too, this rich mixture will cause an amount of bore-wash (literally washing the oil from the bores) the cold unloaded engine will not ?light up? the catalytic converter reducing its life and increasing emissions unless you drive the car long enough to undo the damage to the cat. Camshaft wear is also at it's maximum at idle - with cold oil you not doing it any favours.
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If I got in my car on a winter morning, started it and drove off, I would not see a damn thing. Even if you use de-icer, the windscreen can re-freeze as you drive off. I've seen people coming torwards me, weaving all over the road because their windscreen is still iced up. I live on the edge of a village next to fields which means the car is heavily iced up. It might be alright for urbanites, but not practical here. Engine is still fine after 5 years of ownership.
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If lots of people turn off their engines waiting in traffic queues, then when the lights turn green, fewer people will be ready to move off smartly.
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My comment regarding Excessive idling refers to parked vehicle only. Regards Peter
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