I currently park on a slope everyday at night and in the morning I just let it roll a bit and start it by putting it into the second gear. I started doing this when I had a weak battery. And now even with a new battery I sometimes do it out of habit.

Will this cause any kind of damage or faults to the car?

And I have noticed that I can even start my car even while keeping the key only at the unlock steering position and need not put it in the ignition on position. I started starting it this way because it doesn't give a sudden jerk feeling while putting into the second gear while moving, but starts up the car anyway and then I key to ignition position and continue driving.

Why doesn't the car jerk in this method compared to normal way with the key all the way turned in?

Note: My Car is an old 2005 Peugeot 206. Location Germany if that matters.

Edit: Let me rephrase the second question.

Ignition Key Positions

I have noticed that I need not keep the key in Position ON to kick start the engine. Even with position ACC, the engine starts up but with less lurching, while keeping the key in ON position turns the engine with a hard lurch.

Could anyone explain why there is a difference in behaviour during the kick start based on the ignition key position.

  • are you saying you can start it and drive around with the key in the accessory position?
    – agentp
    Apr 6, 2018 at 0:09
  • I can start it but need to turn key to ON soon else it shuts off.
    – Max Payne
    Apr 9, 2018 at 15:59

3 Answers 3


Will this cause any kind of damage or faults to the car?

It won't cause too many issues, but does cause extra wear/tear on the drivetrain. Your transmission/clutch/flywheel weren't really designed to be doing this all the time, so they'll take the brunt of it.

Why doesn't the car jerk in this method compared to normal way with the key all the way turned in?

Actually, unless you typed this wrong, I would be surprised if it doesn't lurch using this method and would wonder why it does with regular starting? If you typed that wrong, it's a bit herky/jerky when you pop the clutch because mainly of your tires and give in related suspension parts as it tries to get the engine caught up to the rest of the car. There would normally be a pretty good heave to it all and then it starts spinning along with the rest of the drivetrain, as away you go. When using the starter, the torque from the starter is all internal to the engine, so has no affect on the suspension until after the engine is started, at which point you'll get an amount of torque being applied through the motor mounts from the engine itself.

  • I have rephrased the second question. Hope it's clearer what I originally wanted to know.
    – Max Payne
    Apr 5, 2018 at 18:45

Will this cause any kind of damage or faults to the car? I don't believe the actual bump start itself is a big deal, however, driving with a low/dying battery will kill your alternator (usually a $150-250 part.. fairly simple replacement). Your alternator is only good for delivering so much amperage, and if more than that is demanded, it's life will dramatically decrease. Charging a low battery repeatedly will eventually end in a dead alternator, as will running a car with a battery near the end of it's life-cycle. (One which doesn't properly hold a charge)

WRT the lurch not happening when the key isn't turned, I suspect it's because while you are turning the engine, the spark plugs are not actually engaged, so it sounds like it's running, but you have no fire. If not turning the key to the 'on' position before the car stops rolling (or you put it in neutral) causes the car to die, then this confirms the plugs are not firing. When you bump your car, you are turning over the engine which generates electricity for your plugs, moves the gas through the system, works the pistons and the like. If the key is not in the 'on' position, however, certain electrical circuits will still be in the 'off' position which could include (and probably does) the plugs.
Note that if the electrical system isolates the battery from the alternator when the key is in the 'off' position, then generating electricity without a battery to store it in will also damage your alternator.
Normally, when you bump your car with the key on, the fire from the plugs causes the engine to start it's own cycle, and as that process catches up, then passes the speed at which you are traveling (because second gear doesn't want to idle at super slow bump-speeds, and you're likely adding a bit of gas to prevent stall anyway), you get a lurch in your vehicle. Third gear would lurch less but stall quicker, and if you could get it to start, first gear would lurch more for a shorter distance because of the torque each gear provides.

  • And if you have a dying battery, the eventual jump start will fry your electronics, because when you disconnect the jumper cables, the battery isn't able to buffer the rapid electrical change in the system, resulting in a voltage spike.
    – juhist
    Apr 4, 2018 at 19:24
  • If you don't turn the key to the 'on' position before the car stops rolling (or you put it in neutral), does it stop running again? --- Yes I need to turn it ON as soon as the engine starts else it shuts off even in neutral gear.
    – Max Payne
    Apr 5, 2018 at 18:49
  • That confirms the plugs are not firing when the key is not in the 'on' position. I rephrased my post so that is no longer a question as well. Apr 5, 2018 at 22:43

A habitual bump start is not a good idea, as the repetitive shock load on the crank shaft can cause it to break.

There are some vehicles that a bump start has been known to break the crank due to letting the clutch up too fast - we had a VW camper that had 3 engines due to bump starting...

But this is based on my experience and I have bump started many vehicles (cars, tractors, lorries etc) so take care when releasing the clutch - you need to be smooth...

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .