Why Your Car May Start with Jumper Wires then Die when Removed

When a car fails to start, it is common to reach for the jumper cables, give the car a boost charge and then start it.

When it starts successfully, it is usual to assume that the battery was drained, right?

But what if the car cuts off shortly after removing the jumper cables?

Is it an alternator or a car battery problem, both or some other problem?

Read on, for a list of likely causes why your car engine may stop running after removing the jumper cables plus checks you can do to quickly narrow down the problem.


Why the Car Engine dies when Jumper Cables are Removed?

If the car engine dies after removing the jumper cables, check that there are no accessories that may be competing for power from the alternator.

There is a good chance that there is a problem with the alternator or its connections.

Once the car has started, it relies on the alternator as the primary source of power to keep running unless there is a demand for power that cannot be met by the alternator in which case the battery supplies the additional power.

Another sign you can look out for is the battery light on the car dashboard.

If the battery light is on, then you might have a problem with the alternator.

Take your car to an Autozone to have the car alternator tested.

Related questions

Why a Car May Fail to Start on After Being Successfully Jump started?

If the car fails to start after jump-starting and switching off the engine, then you may have loose connections or contacts at the alternator and battery.

Let us look at what checks you can do.

#1. Loose battery and alternator connections

Confirm that the cable battery and alternator connections make good firm contact.

You need to inspect the battery cable connections, alternator plug and the ground connection from the battery to the car’s chassis.

Confirm that they are clean (no corrosion) and that they make firm solid contact.

#2. Faulty Battery

If after jump-starting and running the engine for several minutes to top up the car, the car engine runs fine and then you switch it off.

If it still fails to start and needs to be jumpstarted each time then runs fine and until it is shut off, then it is likely there is a fault with the battery.

There is a good chance that the battery cannot hold charge anymore and should be replaced. Have the battery tested at an Autozone.

Final Word

All in all, if you are able to jumpstart your car and then the engine dies after removing the jumper cables there is a good change that you have a faulty alternator.

The alternator is the primary source of power and supplies power to the car’s electrical system to keep it running.

On the other hand, if you are able to jumpstart, run the engine for several minutes to top up the car then the car engine runs fine until you switch it off but needs to be jumpstarted each time, then you probably have a faulty battery or connection.

Note, this is just a guide and additional tests may need to be done at an Autozone to confirm where the problem is.

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