This confirmed that, yes, revving the engine does make a slight difference in the amount of voltage supplied by the donor car. However, it was a gain of merely a few hundredths of a volt—not enough to revive a dead battery.
The battery will charge faster if you rev the engine faster. Why? Because the faster the crankshaft turns, the faster it turns the belt that runs the alternator. And the faster the alternator turns, the more electricity it produces to run all the electrical stuff in the car — and recharge the battery.
Once you're hooked up, leave the live vehicle running and connected, running the engine around 1,500 rpm to boost the charge a little bit. After a few minutes, you should be able to start your car.
Once all the cables are placed correctly, start the car with the live battery. Lightly hit the gas (in neutral) to start transferring power to the dead battery. Let the car run and keep lightly pressing the gas pedal for about a minute. Then try to start the dead car.
Another helpful tip to help jump-start a car is pressing the gas pedal during the ignition process. Slightly revving the engine might help the process along. Once you're done, remove the jumper cables starting with the black cables on both cars.
The fuel injection system does nothing until the engine is turning (starting or running), so pressing the pedal before you start will make no difference. The fuel injectors work at any RPM, so a choke is not necessary.
RAY: So by revving your engine up to 2,000 rpm or 2,500 rpm and holding it there while the other car tries to start, you're increasing the output of your alternator and giving your battery a little bit of extra power, which it can donate to the other car.
Have the driver of the vehicle with the good battery turn their engine on and allow it to idle for a few minutes. Leaving the other car running for a short time will allow your dead battery to recharge before you attempt to start your engine.
As far as jump starting on any vehicle, particularly if the charging system on the vehicle doing the jump starting is smaller than the one on the vehicle with the flat battery, it may be necessary to rev the vehicle for 5 minutes with the jumper leads connected to charge the dead battery as the battery, starter motor, ...
How long should you leave the car running after a jump? It's best to drive the car around or let it idle for at least 30 minutes after you jump-start it. Ideally, you should drive the car around for 30 minutes to allow the alternator to charge the battery to a good level.
Push in the clutch (do not release until step 4) and put the car into second gear. Turn on the ignition. Have your friends start pushing the car, or let off the brakes if you're on a hill. Once you're moving at a fast walking pace, bring up the clutch quickly and the engine will start.
How Long Does It Take to Jump a Car? If you're going to jump-start your car by yourself, you can expect the process to take about 10-15 minutes. If you have a professional jump-start your car, then it might take a little less time.
At highway speeds, your engine's running hard enough for the alternator to send spare amps to the battery. But when parked, the engine doesn't have spare amps. No, you can't charge a car battery while idling. At best, it'll charge the battery a few amps, but not nearly the hundreds of amps it took to start the engine.
Once you've got the cables connected, jumpstarting your car should only take a few minutes. Like five minutes tops in normal cases and 30 minutes in extreme conditions. To fully recharge the battery, you must drive for at least 15 minutes after starting the vehicle.
Don't leave your car sitting idle or it won't charge as quickly. After 30 minutes, your car should start again next time and each drive after that will continue to charge it.
But while this may get you going again, did you know that jump starting can damage your vehicle's sensitive electronics, leading to expensive repairs, as well as causing lasting damage to your battery?
If the battery is completely dead, it won't have enough power to turn over the engine, even with a jump start. In this case, you'll need to replace the battery to get your car running again. Another reason why a car battery won't jump is because there is a problem with the charging system.
It's more often the flywheel - which is the larger gear that the starter gear meshes with. They're both pretty tough, and accidentally starting the car when it's already running once in a blue moon probably will not do any damage. If it's done repeatedly, though, you can wear down or break a tooth on the flywheel.
First off, when you have to continually press the gas pedal in order for the engine to start, it means one of two things - either the engine is not getting the right amount of air/fuel ratio or it's unable to ignite that mixture of fuel and air.
There may be some cars where you have to press the brake pedal before starting the engine, but it is not a ubiquitous feature as yet. It is not necessary to push the brake pedal to start the car and since the car is in park, the car isn't going to roll. the car isn't going to start unless it is in Park or Neutral.
As long as the current rating is at least 400 amps, yes. If the 12-volt battery is sufficiently charged, and produces enough amperage to make up for the original battery's shortfall, you can.
Caution: Don't attach the negative cable to the negative terminal of the weak battery when jumping a car battery! This common mistake could ignite hydrogen gas directly over the battery. Battery explosions can cause serious injury.