Switching cars off when they're goin...

[Tumble]

righty... tried this all last nigfht in the B&Q carpark... my Mini, which has a super-new shiny power steering system, works off both the engine AND a spearate motor (listen to one stationary as it turns it's wheels) so when the engine turned off, the steering went a little heavier, and got heavier as the engine ran down to a standstill. There wasn't a huge jerk as the engine shut off either - essentially because turning the key does 2 things. 1) at the first click, the fuel pump is switched off. At the second, the ignition circuit is turned off.. so no feul.. no spark.. but the engine is still turning - it doesn't need either of those 2 things to be turned, but it does to turn itself.

I also tried it in the Landy, which has an agricultural to say the least steering system.... this is purely driven off the engine via a belt, and therefore the steering did not immediately get any heavier until the speed of the engine started to drop off - the same thing happens when the key is turned in the Landy - the fuel pump turns off, but there's no ignition to speak of in a Diesel, so the electrical bit of the key turn involves turning off the lighting system and ancillaries..

Now then.. starting.. both motors started without a shudder while the thing was still rolling obviously clutch in... but jump starting is not a problem if you do it right. There isn't really much difference between jump starting and turning the key, you're basically spinning the engine, overcoming the compression and drawing fuel into the bores and igniting it, in order to create a sustained combustion. both methods have fuel running through the bore without igniting initially - probably more when you use the key. If you do have to jump start a car, it's usually because the battery hasn't got enough power to turn the engine fast enough to light it, or if it's a Diesel, maybe it's cold annd the heater plugs aren't working very well... in either case - don't just keep cranking the engine.. you want a bit of battery to jump it.

So.. off you go down the hill, or being pushed if you've got good/gullible mates shift into second gear - you only need a slow speed to get it going and as you bring the clutch up, turn the key as if your starting it. This will get rid of the initial compression by turning the engine over, there may not be enough juice to get it going properly, but the weight of the car comes in now - gives it enough inertia to spin it up properly. By turning it - when you bring the clutch up, you don't get the buckaroo effect, it saves a lot of stress on your gearbox and your driveshafts and sounds a hell of a lot less harsh. works everytime as well. It's like towing a car out of a muddy hole - it aint got enough go to get out on it's own, but more often than not, 1 bloke leaning on a towrope PLUS the car giving it peanuts will get it out.

[Zak33]

that Mini has hydro electric power steering...soit has a capacitor storing energy...

Corsa got it on 1.2's ages ago...was dreadfull if you wound the steering a lot, it ran out of charge

New Corsa is vastly superior.....and the idea is that it switches off at speed....and saves you fuel

Landy.....old style as you say, so igniton off is no problem....solong as in gear and rolling

Some older Vuaxhallsused to benefit greatly on some days from a key off....roll ....key on thing....cos somedays the injection system mis read ambient temp or similar and underfueled....

a quick motorway 70mph restart and it was back to full power...

Trig might have done that at times...the red top 16v Cav engine apreciated it sometimes....

DONT FORGET>>>>>NOT KEY OUT>....FFS....JUST OFF

[dkmech]

Thanks for the detailed info Tumble.

[BUFF]

Good God , a Landy with power steering - never had that in my days of driving them

You do know that jump starting cars with catalytic converters is not a good idea - it is bad for the cat?

[dkmech]

Yeah, i already told them

[[GSV]Trig]

I tried it on an old F reg cav lx, cos the fuel pump was fed off the cam if the engine was turnin it was pumping, needless to say when u turn it back on again u get a massive backfire....

[dkmech]

So i was right about it on at least some of the cars.

[[GSV]Trig]

Yeah this was an old 1600 Cav with a carb tho, none of this elastictrickery under the bonnet...

[Tumble]

Good God , a Landy with power steering - never had that in my days of driving them

You do know that jump starting cars with catalytic converters is not a good idea - it is bad for the cat?

Jeeez.. how old are you man?? my cars 18 years old in October

[Zak33]

You do know that jump starting cars with catalytic converters is not a good idea - it is bad for the cat?

nope...

BUMP starting is bad....(pushing and popping the clutch) cos the fuel goes in and doesnt burn..right out other side...into exhaust.....and then when it DOES catch....it can really catch

JUMP STARTING with leads......is fine

[dkmech]

I think that the bump starting is what BUFF meant. When i said it i called it push starting, it was Tumbler who called it jump starting so Buff just carried on with the same terminology.

[Tumble]

well the only things I've bumoed are me landy, an old fiesta from the year dot and some Dieseasel vans...

[BUFF]

I think that the bump starting is what BUFF meant. When i said it i called it push starting, it was Tumbler who called it jump starting so Buff just carried on with the same terminology.

Correct.

& I used to drive Landys in the military up till about 1988 - try driving a truck without power steering if you want a good workout.

[Tumble]

heheh.. driven me mate's SIII lightweight round a trials section... tell ya, no wonder he's built like the proverbial outhouse...

[Rave]

I had to bumpstart my MR2 on my own a few times when the battery died. One time it took me so long to get it started that I thought my lungs were going to pop out! I found it hard to drive for the first few minutes 'cos all my muscles were shaking so much! Naturally that was the day I was already late for work.

OTOH my Brother and I managed to bump his big diesel Luton van once with no trouble. Having someone to sit in the cab and pop the clutch makes all the difference.

I fail to see how bumping a car would be bad for the cat. If anything the engine catches quicker if you're going at a decent speed when you bump it, so what's the difference? My mum's old 2CV quite often wouldn't start with the starter motor but a bump would get it going pretty quickly.

Rich :¬)

[streetster]

hah... my electronics teacher told us he had a mate who bought a brand new car to replace whatever old one he had.. and every day he used to turn off the engine and coast and turn into his driveway.. except with the new car the steeringwheel locked and he went straight into a lamppost hoho, unlucky for him

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