Car Repair and Maintenance

Reasons Car Won’t Start with Jump Explained

Your car won’t start with jump? Well, new or old, a car will need a jump at some point to start. And if it won’t start, there are possible reasons for this.

Normally, you jump your car with jumper cables or with another car.  Some other times, pushing to start may work. But when any of these conventional methods won’t work, charging your battery should not be the only remedy you consider. The jump problem could signal other major problems you need to resolve to prevent a jump inconvenience in the future.

Car won’t start with jump

Car won’t start with jump

If your car won’t start with a jump, below are possible causes and how to fix them:

1. Damaged/dead battery

Your car battery ensures supplying power to various parts of the car for it to work properly. It’s still possible to jump a car by connecting the bad battery to a fully charged one with jumper cables—Haynes.

However, how dead the car battery determines whether or not the jumper connections may or may not start your car immediately.

How to fix

From the explanation above, you can deduce that your car may not start because the battery is too dead. You should make sure your battery has sufficient power by replacing it every 3-4 years, according to experts.

2. Faulty starter motor

Your car won’t start with jump if the starter motor is faulty. Generally, the better provided the starter motor with the energy for it to spin. Thus, a defective starter won’t crank the engine to power it.

To tell if your starter motor is faulty, you’ll get a clicking or grinding sound when your car engine won’t turn over.

How to fix

Your solution is to go to a repair shop. In some cases, an auto electric shop will be able to rebuild or repair a faulty starter with shorted field windings, bad commutator, bad armature, bad brushes, or even a bad solenoid. You’d have to wait for some days though. Otherwise, get a replacement starter motor.

3. Malfunctioning alternator

If your car battery is below 3 years but doesn’t start the car after a jump, it’s possible that the alternator is bad.

Understand that just the battery is not enough to power the car’s electrical system, so the alternator is an important factor. An alternator will typically restore any lost electrical power in the battery and provide current to the electrical accessories while the engine runs.

If you have a multimeter, you can tell if your alternator is bad. Do the following:

  • Set the multimeter to DCV (DC Volts) above 15.
  • Clean the positive and negative terminals of the alternator.
  • Attach the black cable of the multimeter to the negative terminal and the red cable to the positive terminal and look for an alternator reading of around 12.6.

If the reading looks off, the alternator could be the culprit, and you have to contact an auto repair shop to get your car to start again after a jump.

4. Corroded battery terminals

Your battery terminals need to be in good condition for the car to jump start. Thus, if loose or corroded, the terminal connections block electrical flow from the donor battery, keeping the car from responding to the jump.

How to fix

The common fix for this problem is to remove the cable ends and clean the corrosion using a wire brush. Consider retightening the bolts to ensure contact and restore full electrical power to jump the car.

The ground side of the negative battery cable bolted to the engine block is often overlooked, so ensure to clean the connection and tighten it to start the car with a jump.

5. Faulty jumper cables/connection problem

Your jumper cables could be the reason the car won’t jump start. Thus, you want to examine the quality of the jumper cables. Some jumper cables won’t carry enough current (typically the too long or too light ones) and can get damaged easily, causing a jump start to fail. Light jumper cables also come with excessive internal resistance.

Look out for jumper cable melting, that alone can tell that you have low-quality jumper cables.

In other cases, improper jumper cables connection will not allow your car to jump-start, even with a good battery.

How to fix

The simple solution is to buy a set of high-quality jumper cables. Jumper cables are measured in gauge, and the lowest gauge number shows the thickest cables. Thus, a smaller gauge indicates thicker cables, and thicker cables can carry more current (amps). All in all, you need the thicker (small gauge) cable for your battery to jump.

6. Neutral or clutch safety switch

If your car has an automatic transmission (AT), it uses a safety feature that stops it from starting when it’s not in park (P) or neutral (N).

How to fix

If you have a manual transmission vehicle, step on the clutch pedal for the engine to start. And if the safety switch is faulty, your car won’t jump start.

7. Clogged fuel filter

Fuel filters help your car to make sure only clean fuel enters the engine. As a result, filtered debris eventually builds up and clogs the filter, preventing gasoline from reaching the engine. Thus, even with an excellent battery and alternator, your car won’t jump start, as your engine can’t run without gas.

Read also: alcohol can be the new gas

While the fuel filter may clog, you also want to be sure you’re not running an empty tank, so check your fuel gauge.

How to fix

The solution is to clean or replace your fuel filter after about 20,000 to 30,000 miles. Note that this expert recommendation depends on the make and model of your car. Your vehicle owner’s manual provides a more accurate estimate in this regard.

8. Bad ignition switch

Your ignition switch could be faulty, preventing your car from jumping with cables, another car battery, or even pushing. The ignition switch turns on and starts a vehicle.

However, it can damage over time to wear and tear. You can tell if the ignition switch is bad if you’re sure your battery is in good condition but the car won’t turn on after a few tries.

How to fix

It can be straightforward to repair the ignition switch or assembly with labor costs between $80 to $200. However, if the key won’t turn, the labor price increases since removing the ignition switch may require turning the cylinder.

Tips to look after your car battery


Your car battery won’t last forever but you could still extend the operational life with the following tips:

  • Have a professional check battery condition.
  • Turn off interior and exterior car lights when not in use. If lights won’t turn off in your car, check these.
  • Tighten the battery well enough.
  • Clean dirt, corrosion, and grease from the terminals.
  • Check battery voltage often.
  • Disconnect the car battery when you won’t be using the car for a long time.


Usually, troubleshooting makes it easier to detect the reason your car won’t start with a jump. A bad battery is a common cause, so consider boosting your battery and monitoring how fast it discharges after charging. If all fails and you find yourself in an urgent situation, contact your local car jump-start services or a tow to help power your car. In cases that require repairs, contact your local mechanic.

Latest posts by Bernard Juchli (see all)

Bernard Juchli

Bernard Juchli is an experienced racer, mechanic and team owner who trusts Avon Tyres.Bernard is the lead driver and force behind his Big Dog Garage Race Team. He is the General Manager and Chief Mechanic of Jay Leno’s Garage. Bernard and his crew of seven are responsible for all repairs, restoration and fabrication of Jay’s incredible automobile and motorcycle collection.

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