Anybody bump started car with an automatic gearbox?
Discussion
Anybody here managed to bump-start a car with an automatic gearbox apart from me and 530dTPhil?
But has anyone else tow-started or bump-started a car with an auto gearbox? What speed? Any damage/problems?
530dTPhil said:
I did it many years ago with a Beetle automatic. The handbook said tow to about 25 mph and engage drive -- it worked! Never tried it on any conventional automatic though.
^from the "Correct way to push-start a car" thread.G350 said:
Free-wheeling in neutral with the engine off down a very long stretch (>10 miles) of deserted desert dual carriageway in the middle-east, put the ignition on and just snuck it into D and the engine started in a very smooth and undramatic way. Easy peasy. Not tried it in my other automatics.
1995 model Jeep Grand Cherokee, full-time 4x4, 4-litre 6-cyl, 4-speed autobox.
Most driver handbooks warn against it, some threatening serious gearbox damage. Also due to the probable speed involved it is possibly not the safest thing to be doing.1995 model Jeep Grand Cherokee, full-time 4x4, 4-litre 6-cyl, 4-speed autobox.
But has anyone else tow-started or bump-started a car with an auto gearbox? What speed? Any damage/problems?
Welshbeef said:
But you shouldn't bump start even manuals since catalytic converters were introduced as the unburnt fuel kills it and a new cat is not cheap and if exhausted is an mot failure.
Don't bump start cars
That's a good point. My Jeep was a leaded-spec car with no cat.Don't bump start cars
Here's what it says in my 2011 BMW 3-series handbook:
...With a catalytic converter, the vehicle should only be tow[-started] when the engine is cold; with an automatic gearbox, tow-starting the engine is not possible...
Welshbeef said:
But you shouldn't bump start even manuals since catalytic converters were introduced as the unburnt fuel kills it and a new cat is not cheap and if exhausted is an mot failure.
Don't bump start cars
A cat can take quite a bit of fuel before it breaks. I drove over a hundred miles with a dodgy coil with one cylinder pouring neat fuel into the exhaust. Cat was fine as were emissions at the last MOT.Don't bump start cars
I guess there is tolerence with regard to bump starting manual cars with catalytic converters - BUT you don't know how many times you can do it and how many times it's been done before and also with age it may be the straw that broke the camels back.
Get breakdown cover instead.
With auto's firstly if the engine is running and let's say you accelerate up to 50mph push it into N and then let it coast down to 40mph and push it into D? Anyone tried anything like that?
Get breakdown cover instead.
With auto's firstly if the engine is running and let's say you accelerate up to 50mph push it into N and then let it coast down to 40mph and push it into D? Anyone tried anything like that?
Welshbeef said:
With auto's firstly if the engine is running and let's say you accelerate up to 50mph push it into N and then let it coast down to 40mph and push it into D? Anyone tried anything like that?
Yes, loads of times with the G-wagon, Forester and others. No probs. It just slips back in to gear - bit like letting the clutch out in a manual.Not tried it in the E91 (yet) as its only done 000200 miles
Why you ask?
i don't see how the cat is any more or less washed with fuel by bump starting than tow starting, or even jump starting with the engine being spun by the starter?
i think it's maybe just H+S because someone in america managed to get run over by their own car or something?
like the 'bump starting a car can skip teeth on the cambelt and destroy the engine' bks
i think it's maybe just H+S because someone in america managed to get run over by their own car or something?
like the 'bump starting a car can skip teeth on the cambelt and destroy the engine' bks
Once successfully, once not so successfully. The success was an old series 3 XJ6, down a rather large hill with no traffic, as a last resort after it wouldn't start. No idea what I would have done with a two ton Jag doing 35mph(ish) if it hadn't fired up by the time I got to the bottom, as they're a cow to deal with when you don't have power steering or servo brakes working.
The one that went wrong... a 1991 Ford Granada. Spurred on by the way the Jag coped a few years earlier, I tried it with the Granada when it misbehaved. Engaging "drive" at about the same speed resulted in a large bang, then crunch tinkle grind. The auto box was not happy at all.
Rich
The one that went wrong... a 1991 Ford Granada. Spurred on by the way the Jag coped a few years earlier, I tried it with the Granada when it misbehaved. Engaging "drive" at about the same speed resulted in a large bang, then crunch tinkle grind. The auto box was not happy at all.
Rich
Edited by richw_82 on Thursday 3rd March 15:12
Success in bump starting an auto will entirely depend on the gearbox. If it doesn't have a pump on the output shaft then it won't have any line pressure with which to engage a gear - no amount of towing will get the engine to turn over. Most modern autoboxes have their HP pump on the input shaft so it won't work. I could envisage that a electrically/solenoid controlled box would work also. I am obviously excluding the latest generation of stop/start (engine) hybrid autos though - they mostly have some kind of hydraulic accumulator to enable the gearbox to continue work without the engine running.
Russ
editted for grammar (which is still probably rubbish).
Russ
editted for grammar (which is still probably rubbish).
Ozzie Osmond said:
russell_ram said:
Most modern autoboxes have their HP pump on the input shaft so it won't work.
^^^^ This. If the pump's not running the transmission can't function.Some of the older borg warner/triumph/bl auto boxes you could tow or bump start but you had to chuck a couple of litres of extra fluid in first.
I personally wouldn`t attempt it on any modern auto box.
on the subject of cat damage by bump starting its no worse than when you crank the engine over before it fires.
Unless it fires instantly,its still pumping fuel into the cat.
And certainly no worse than sitting there cranking a non starter over for ages if for instance the coil pack failed.
I personally wouldn`t attempt it on any modern auto box.
on the subject of cat damage by bump starting its no worse than when you crank the engine over before it fires.
Unless it fires instantly,its still pumping fuel into the cat.
And certainly no worse than sitting there cranking a non starter over for ages if for instance the coil pack failed.
Never tried to bump start anything with an auto box.
I'd be wary about bump/tow starting anything with a floating crankshaft pulley for the cambelt. I may know someone that did this to a 2003 renault megane diesel and it resulted in 6 of the valves bending themselves, 2 valve guides cracking and the camshaft journals splitting in half
My late father ran a fleet of 150 Mothers Pride vans which were BMC 2.2 taxi diesels with BW 35 autos. Exciting as a 14 year old being dragged around a yard at 25-30MPH especially when it was icy or snowing! These were dual pumped so would tow start but most boxes as people have said only have pumps on the input shaft, so cannot be tow started. Unless a 100% sure it can be tow started DON'T as you'll destroy the box if you try. The cat won't worry as the minute the engine starts it'll light up any excess fuel anyway.
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