# Bump starting



## ramos (Nov 1, 2008)

On a rally at weekend we were helping a friend get started. The jump leads were car leads and got to hot. When someone said OK lets bump start it. I said dont be silly you cant bump start a diesel. Oh get a life he said where have you been hiding. But before we could settle it a heavy duty set of leads were found and we got him started. So my question is Who was right.
ramos


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## JohnsCrossMotorHomes (Jul 21, 2007)

Diesels from cold need a high rev to get them going due to the combustion in the cylinder relying purely on the heat generated by the compression of the fuel/air mixture in the cylinder.

One way is to pour a quarter cup of unleaded petrol down the air inlet or over the air filter in an emergency and give it a good bump start in third gear (if one does not have a can of easy start)

Same applies to a stubborn petrol engine that does not want to start, but dont spill the petrol!

Peter


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## ramos (Nov 1, 2008)

*ump start*

Hi Peter. Cheers. So what they sugested ,simply a few of us pushing this tag axle across the car park in the frost wasn't really going to get it going was it. So basically You cant (easily) bump start a diesel.
Ramos


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## UncleNorm (May 1, 2005)

I'm shocked! 8O 8O 

I had been led to believe that BUMP starting wrecked the very expensive catalytic converter that is fitted to more modern vehicles. 

Experts needed please!


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## cabby (May 14, 2005)

I have seen a dozen of us bump start a lorry before now, it is easier if you are on a slope, but you just need room to build up revs to generate heat in the bores to ignite the fuel.but it sounds in your case that there was not a lot of room. also it sounded that the jumper leads being used were rubish, but could have worked given a longer time allowance before trying to turn over the engine.Please try not to use easy start, the engine will become dependent on it to start.seriously. 

cabby


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## erneboy (Feb 8, 2007)

Old diesels had a manual stopping device, a knob you pulled to stop them and and pushed in when you wanted to start them. Modern ones have electrically operated stoppers, if the battery is completely flat the stopper will not operate, it will not move to the starting position. In that case you can push or tow the vehicle for ever and it will not start. If the stopper does, as it were disengage then the vehicle will start. As to other damage I don't know. So either of you could have been right depending on the state of the battery, Regards, Alan.


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## locovan (Oct 17, 2007)

Was it hard to push a Motorhome Ramos I have this picture of all you men pushing such a large vehicle what if it had started you would have all fallen on your face.
Glad they got it started the proper way with the right jump leads.
We should all carry a set thats for sure.
Mavis


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## maddie (Jan 4, 2006)

:lol: :lol: Of course you can bump start a diesel,and a sure way to kill a cat is pour petrol down the air intake,a bit like the 4 legged one :lol: 
terry


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## lafree (Dec 31, 2007)

Hi , Never bump start a vehicle that has a cambelt as it will tear the teeth off the belt or let it jump a tooth which will put the valve timing out and then the pistons will bend the valves which will result in a costly repair,Iv'e seen it happen on a ford Escort.
Lafree


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## loddy (Feb 12, 2007)

Ha Ha Ha :lol:


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## aultymer (Jun 20, 2006)

> Iv'e seen it happen on a ford Escort.


Maybe the reason it wouldn't start and needed the bump was that the belt was stripped before the bump. Just a thought since I can't see a difference between a starter turning the flywheel or the clutch doing it. 
Have started tractors (top gear), busses and cranes with a tow/ downhill bump (people I worked for were to mean to buy batteries ) and never bust anything yet.


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## johng1974 (Jan 17, 2007)

yep you can bump a diesel  it runs a higher compression and therefore needs a bit more effort...

I have heard about the cambelt jump, but still cant figure out why it would happen...


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## Wizzo (Dec 3, 2007)

aultymer said:


> > Iv'e seen it happen on a ford Escort.
> 
> 
> Maybe the reason it wouldn't start and needed the bump was that the belt was stripped before the bump. Just a thought since I can't see a difference between a starter turning the flywheel or the clutch doing it.
> Have started tractors (top gear), busses and cranes with a tow/ downhill bump (people I worked for were to mean to buy batteries ) and never bust anything yet.


I would be inclined to agree with your logic except that years ago when I had a Honda N600 mini with chain driven OHC I twice managed to make the chain jump one tooth round the sprocket when bump starting it. This never happened when using the starter.

The car was 11 years old and had done nearly 90,000 miles without the timing chain having ever been renewed. (Mea Culpa).

JohnW


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