Bump Starting - Safe?

[BobbyG79]

What's the deal with bump starting these days?  I keep hearing that it can cause "engine damage" but wondering if this is a rumour AA guys spread to keep themselves in business??!!

[kenfowler3966]

Not sure but there was some mention of likely damage to 1.2 petrol if the car was allowed to roll back in forward gear whilst simply using engine and gears to stop rolling back down a hill if brakes slipped. That could easily happen whilst attempting to bump start.

Indeed modern electrical systems just may not work and bring the engine to life? No doubt others know more.

[Smokeyjoe]

Jump Starting is probably better. If the car does not start during a bump start attempt, there may be issues with power steering and brakes not working very well.

[Rooted]

We know we have done it for decades, we know how some failed badly, and millions more just started a vehicle.

 

These days, some people never think, 

there needs to be the steering lock off, if it does not start there is no power steering or servo brakes, i have an Electric Parking brake, 

if there was not enough power to start did the fuel pump prime. 

If we run it down the hill and it does not start what do we do then. 

[weasley]

There are all sorts of 'reasons' why it isn't a good idea, including (off the top of my head):

 

- no power to the fuel injection system

- no ECU boot sequence

- various other systems not primed/booted (fuel pump etc).

 

In reality though...?  I think in a bind I would bump a car if it was that or face some bigger problems.  I know once or twice I 'bump started' the Yeti after accidentally stalling it whilst still having some forward motion (but this meant I had power and a warmed/primed engine).

[KenONeill]

Being an "old git", I remember the original reason for not bump starting cars with catalytic converters being "unburnt fuel getting into and damaging the cat". This probably still stands for petrols (even if you have sufficient battery volts to run the EMS).