Why does push starting work

Sign up to join this community. The best answers are voted up and rise to the top. Stack Overflow for Teams — Collaborate and share knowledge with a private group. Create a free Team What is Teams? Learn more. How does "pushing-start" a dead-battery manual car work? Asked 6 years, 9 months ago. Active 6 years, 9 months ago. Viewed 69k times. Improve this question. Cal Gibson Cal Gibson 1 1 gold badge 3 3 silver badges 15 15 bronze badges.

The starter just turns the car's crank shaft. Putting the car in gear down hill also turns the crankshaft. You're using gravity to do the same job as the starter. Add a comment. Active Oldest Votes. For older designs without electronic ignition and controllers, no battery is required at all. Improve this answer. Alfred Centauri Alfred Centauri Make sure you put your thumb over the handle and not around it.

Then when I inserted the key a dim lights appeared on the dashboard but they faded away very soon - so I knew that the battery was completely empty. Anyway we tried to push start it several times on the street but it did not started. I suppose there were not any electricity for the car computer or spark plug to ignite any cylinder. We wasted our time. The ignition key is then released, the starter ceases to turn, the starter drive shaft retracts, and the engine remains running under its own power.

This is because there is no power to engage and operate the starter. If the vehicle has a manual transmission , however, it can be started by executing a push start. Accomplishing a push start on a car is a simple procedure. He or she must then turn the ignition to the on rather than start position, place the transmission in neutral, release all brakes, and press and hold the clutch in. Next, another person or people, or another vehicle, pushes the car to a speed between 5 and 10 miles per hour.

When your vehicle is going at a jogging pace, drop the clutch pedal — do not release it slowly! The sudden release of the clutch should be enough to get the car started. If it does not work, ask your friends if they can try again. Unfortunately, you cannot push-start your car if it has an automatic gearbox. This applies to dual-clutch transmissions as well. This is because the manual friction clutch provides a positive coupling between the driven wheels and engine.

But this is not the case with an automatic transmission, which has a fluid coupling. The dual-clutch gearbox uses a friction plate clutch arrangement, and the selection for drive is controlled by a mechatronic system. It needs both electrical and hydraulic pressure in order to operate. Electrical energy is supplied by the alternator , while hydraulic pressure comes from an engine-driven pump.