Reverse bump start

[Valmave]

If you are facing uphill in a car with a manual gearbox can you bump start it by putting it into reverse gear and rolling backwards ?

[carrust]

Yes you can.

[Hymie]

On a flat surface, the optimum gear to ‘bump start’ a car is the 3rd gear – attempting to bump start in 1st gear is likely to result in failure due to the excessive breaking effect of the gearing ratio.

Since reverse is normally lower geared than 1st, it would have to be quite a steep hill to achieve success - better to change the car's direction and use 3rd.

[Hymie]

'Braking'

[beso]

In addition to what Hymie said. Too low a gear stresses the engine mounts. Go easy on releasing the clutch rather then letting it right out.

My new Hyundai advises not to bump start as it can damage the engine management system.

I assume this is because of the sudden surge in alternator output as it cuts in without the large load of the starter cranking. The alternator field is fully powered but the alternator is still not producing output due to low revs. This field takes a significant time to decay after the regulator senses the voltage surge but it can be enough to be trouble.

[Toureman]

To conserve your ECU You might be ok by putting your side lights on beso.

[TWR]

Yes.

[woofgang]

Hmmm beso, like you'd do it if you had a choice......

[needawin]

Just remember that if you are rolling in either direction with the engine not running you have no brakes. If the car fails to start you could be in trouble. Keep a hold of the handbrake.