It can be a very frustrating thing when you try to get your car started after it's been parked for a while and you realize nothing's happening. Whether you're in the driveway at home, or you were parked at work or in a parking lot if your car won't get started when you get back in, there aren’t a whole lot of options for what you can do to get it going again. One of the most common solutions to this problem is to get your car jump started.
If your battery has died then you can find a good Samaritan who’s going to hook up their car to yours by some jumper cables to give you a boost and get you going again. But what happens if someone jump-starts your car and it still refuses to get moving? There are a number of reasons why this can happen, and none of them are very easy to overcome in your present circumstances. Let's go over 12 of the most common reasons that your car won't get going again even after you've had a jump start.
Totally Dead Battery
If you are unable to get your car going again after you've had a jump start from a viable battery one of the most obvious causes could be that the battery itself is simply unable to receive a jump any longer. If your battery is too old, it will no longer be able to receive power from even a jump start to get going again. Your average car battery has a lifespan of about 3 years to 5 years. Over time the chemicals inside the battery that create the reaction that makes the power you draw from it wear out. It's the same as a battery that you might have in the remote control for your TV at home. Even rechargeable batteries only have a finite lifespan. Your battery is constantly being charged by your alternator while it's running, but after that three to five-year period is up it is simply unable to retain enough of a charge to power an entire car any longer. At that point no amount of jump starting is going to get it going again.
Loose Battery Terminal
Sometimes the problem with trying to get a jump start and it failing on you is not that there's a problem with the battery per se, which is to say it could still technically receive a charge, but the terminals on your battery have come loose. If that's the case then when you try to jump start the power from the other battery that's connected to yours will actually have nowhere to go and as a result your battery won't charge and the jump start will fail. Always remember to check your terminals before you try to do a jump start on your battery so that you can avoid this situation.
Corroded Battery Terminals
Just as a loose battery terminal can cause your battery to charge improperly, a battery with corroded terminals is subject to the same problem. If you have a serious white crusty buildup of corrosion on your battery, then when you connect the jumper cables to it that layer of corrosion is going to prevent the transfer of power into the battery. Thick layers of corrosion act like an insulator and prevent your battery from receiving a charge and also from properly providing power to your car. When you see that kind of corrosion on your battery the best bet is to get a wire brush and some battery cleaner and polish the terminals until they are clean again. After that you can try to give your battery a jump start. If it's still a viable battery it should work at that point. If it doesn't work, then you have another issue to deal with.
Your battery and your alternator work together to power the electrical components in your vehicle. While your battery is what is used to provide the initial charge to get things going, the alternator actually takes over while your vehicle is in motion and it also recharges your battery. However, if your alternator has failed then it will not be able to take up the slack of keeping the electrical components functioning, including things like your spark plugs, and recharging your battery, which in turn will mean that even if you get your battery jumped your vehicle will not function properly. These two parts need to work together to keep things running.
The starter motor takes power from your battery and gets your engine to crank in order to start the process of getting it to run. If the starter is the problem with your vehicle then giving your battery a jump won't matter because it's not an issue of power in the battery, it's the starter motor itself transferring that battery power into something functional. If your starter motor doesn't actually work then you'll probably hear some kind of a clicking sound as you attempt to start your vehicle, but since it can't get your engine to crank it will go no further than that. If that's the case, replacing the starter motor is your only solution for getting your vehicle to start again.
Bad Neutral Safety Switch
An often-overlooked reason for a car to not start properly is because of a bad neutral safety switch. The neutral safety switch is the part of your vehicle that prevents it from starting when you're not in the correct gear. You have to be either in park or neutral to get your vehicle started because otherwise your car would immediately start driving forward or in reverse. If the neutral safety switch is sending the incorrect signals to your car's computer however then your computer will not realize you are in the correct gear. It may think you are in drive when in fact you're in park. As a result, it will prevent your car from starting. That means even if you get a jump-start nothing's going to happen because your car doesn't recognize that it's supposed to be starting.
Another problem that gets overlooked quite often when it comes to jump starts not working is the jumper cables themselves. Jumper cables are pretty ubiquitous these days and you can pick them up just about anywhere. If you happen to get a really cheap pair on the internet, then they may not be up to the task of actually transferring power correctly from the donor battery to your own battery. They may be only sending a limited amount of power because the wires inside are too thin, or they could have actually broken in the casing and no power whatsoever is being transmitted but you can't tell from the outside. Your best bet is to always use some high-quality jumper cables and make sure they're not too long either. The longer a pair of jumper cables are, the less efficiently they are able to transfer power from one battery to another.
Bad Spark Plugs
Spark plugs only have a limited lifespan, typically between 30,000 miles and 100,000 miles depending on the kind of spark plugs you have. Cheaper spark plugs are obviously going to wear out sooner, while more expensive ones can last as long as 100,000 miles. Although it's very unlikely, it's also possible that two or more spark plugs could fail at the same time. If that were to happen then the reason your car isn't starting has nothing to do with your battery, it's because your spark plugs are not able to ignite the fuel and air mixture in the combustion chamber allowing your car to get going. That means that no amount of jumping your battery will get you going again until you get new spark plugs or you clean up the old ones that aren't working properly. If you have several failed spark plugs, then there's probably an issue with contamination or corrosion that has caused it because all of them naturally failing at the same time is highly unlikely.
Clogged Fuel Filter
Your fuel filter needs to be changed every 50,000 miles or so. As part of its normal function it clears out dirt, debris, and other contaminants that may be travelling from your fuel tank to your engine. Because it is a filter, it is inevitable that eventually it will become clogged. If the clog is bad enough, which is to say that it hasn't been changed in a timely fashion and it becomes completely clogged then your fuel can't flow from the tank to your fuel injectors. As a result, when you try to start your car no fuel will be able to spray into the combustion chamber which means no combustion will be able to occur. Even if you do get a jump start, it won't matter because the battery has nothing to do with why your vehicle isn't starting in this circumstance. The simple matter of replacing your fuel filter can fix this problem for you and get you going again.
Bad Fuel Pump
In much the same way as a clogged fuel filter can inhibit your ability to get your car started, a bad fuel pump will have a similar effect. Without the fuel pump to force the gasoline from your tank to your fuel injectors in the engine, you are not going to be able to create a combustion reaction. That means you will not get your engine to start when you put the key in the ignition and turn it. Since this has nothing to do with your battery, a jump-start would have no effect and would prove useless in trying to get your car started again.
Broken Timing Belt
If your car has a timing belt and it breaks while you're driving it could lead to a catastrophic engine failure. The valves and pistons will no longer be working in synchronization which means that the pistons will likely crash into the valves causing serious damage to many parts of the engine as a result. However, if your timing belt breaks just as you're trying to start your vehicle then you can avert the serious damage to your engine, but you will also be completely unable to start your vehicle.
Because the timing belt connects the camshaft with the crankshaft which allows the valves to open and the pistons to rise in synchronization, without the belt in place your engine will not move at all. This is a pretty rare circumstance but it's not unheard of either and it's also a luckier turn of events than having your timing belt break while you're in the middle of driving.
There's always a possibility that the reason your car won't start even after you have a jump is because you simply have no fuel in the tank. This is an easily overlooked problem, and one that's also embarrassing when you realize it was the problem in the first place. Typically you should be more or less aware of how much fuel you have in your car but it can happen sometimes that you'll simply forget to gas up, you'll have a gas leak somewhere, or someone borrowed your vehicle and they may have brought it back with an essentially empty tank. Obviously trying to jump start your car when the tank is empty isn't going to get you anywhere either. If you notice that the tank is on E, add a couple of gallons and then see what happens.
The Bottom Line
A jumpstart is really only effective in getting your car going when your battery has been drained, usually unintentionally. If you left your lights on by accident overnight, then a jump-start is a good way to get it going again. Also, if your battery is just starting to fail but hasn't completely run out of usefulness, then it's possible you'll have some issues getting started on a cold morning for instance. Unfortunately, there are far more reasons why your car won't start that have nothing to do with your battery and therefore they can't be fixed by a jump start at all. If a jump doesn't work for you, then consider some of these options we've presented as reasons that your car isn't going anywhere and act accordingly.