8 Reasons Why a Car Won’t Start with Jump and How to Troubleshoot It

a car mechanic checking a car that wont jump start

Whether a car is new or not, there will come a time when it won’t start. There are several reasons why a car won’t start. Sometimes a jump is all you need to get back on the road. But what if your car won’t start with jump? Do you know what to do then? Let’s take a look at eight possible reasons and how you can fix them.

Possible Reasons Why a Car Won’t Jump

Jump starting a car is easy, but sometimes it won’t work. There are several reasons why a car won’t start after jumping, such as:

Dead Battery

The battery is responsible for supplying power to every part of the vehicle to ensure it operates properly. This would explain why a car won’t jump start with dead batteries, to begin with. To ensure that your battery has enough power, make it your practice to replace it every 3 years. 

Battery Terminals

The condition of your battery terminals plays a significant role in the jump-starting process. Loose and corroded terminal connections can block electrical flow coming from the donor battery, making the jump-start ineffective. 

Faulty Jumper Cables

It’s important to check the quality of your jumper cables. Some jumper cables cannot carry sufficient current, especially those that are too long or too light. Low-quality jumper cables can be easily damaged and cause a jump-start to fail. 

Faulty Alternator

If your battery won’t jump and it is only less than three years, perhaps you have a faulty alternator. Your battery alone won’t be enough to power all of your car’s electrical system and needs the help of the alternator. The alternator can restore the battery’s lost electrical power and supply current to the electrical accessories when the engine is running. 

Your alternator has to be in good condition for a jump start to work. Sometimes a dead battery is caused by a bad alternator. You should be able to tell the signs of a bad battery from a bad alternator before investing in a new battery. If the signs point to the alternator being faulty, have a professional mechanic fix it as soon as possible. 

Clogged Fuel Filter

Fuel filters are necessary to ensure that only clean fuel goes to your engine. The filtered debris can build up over time, clogging the fuel filter. If gasoline doesn’t reach the engine, it can result in engine failure and a car that won’t start. Even if your battery and alternator are in good condition, the engine won’t run without gasoline. 

Most automakers would recommend changing the fuel filter somewhere between 20,000 to 30,000 miles. However, recommendations may vary depending on your car’s make and model. You can refer to your owner’s manual for more accuracy. 

Faulty Ignition Switch

The ignition switch is one of the most significant electrical components, and it is responsible for turning on and starting your vehicle. You use the ignition switch every time you start your car. Due to wear and tear, it will have issues eventually. If your car won’t turn on after a few tries, and you’re sure the battery is in good condition, you may have a faulty ignition switch. Without a functioning ignition switch, you won’t be able to jump-start your car.  

Neutral or Clutch Safety Switch

Cars with automatic transmission (AT) have a safety feature that prevents them from starting unless it’s in park (P) or neutral (N). On a manual transmission, you need to step on the clutch pedal before the engine can start. Jump-starting won’t work on any car if there’s damage to the safety switch. 

Empty Gas Tank

We often neglect to consider if there’s still enough gas left on the tank. Without gas, cars won’t start even if you jump-start them. Make it a habit of ensuring you won’t have an empty gas tank in the future. 

How to Troubleshoot a Car That Won’t Start with Jump?

Knowing the possible reason why a car won’t start with jump will help you what issues to address and how to troubleshoot them. Here are a few steps you can try to jump-start your car:

  1. Allow the battery to recharge a little longer while connected to the jumper cables. Doing this will give the battery more energy and increase the chances of your vehicle starting. 
  2. Check the protecting rubber coating on the jumper cables. If it’s warm, it means there’s resistance, and the flow of current is minimal. Consider replacing your jumper cables with a different set. 
  3. Examine the battery terminals and look for corrosion. If you see one, clean it off with a brush. Once it’s clean, tighten the bolts, reconnect the cables and try starting your vehicle again.

For non-battery related issues:

  1. Check your fuel gauge or manually check the gas tank to verify if you still have enough gas left. If it’s low, add at least 3-4 liters of fuel before attempting to re-start your vehicle. 
  2. Check for a clogged fuel filter and if they are, make sure your clean the fuel filter or replace them if necessary. 

Tips on Maintaining Your Car’s Battery

While car batteries don’t last forever, you can do something to extend their life. These tips will help keep your battery in its best working condition for a long time.

  • Get your car serviced by a professional to check battery condition.
  • Don’t leave your exterior car lights on. 
  • Check for dirt, grease, and corrosion, and clean it. 
  • Make sure your battery is tightly fastened.
  • Avoid leaving your car unused for long periods. 
  • Check your battery’s voltage regularly. 


A lot of factors can cause jump-starting a car to fail. But if you know the exact cause, troubleshooting it will be a lot easier. 

Most car starting problems are caused by a bad battery, so following the tips above can help prevent future problems. If you’re having trouble starting your car, sometimes boosting your battery can be effective. 

If all else fails, Neighborhood Roadside Assistance in New Jersey and New York has excellent car jump-start services you can count on.