What to Do When Your Car Won't Start or Turn Over

Test these 3 things to get back on the road

Starting car
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It's easy to get frustrated when you get in your car and the engine won't turn over. Don't worry quite yet. If you're at home, there are three things you can test that will tell you what's wrong—and you might have an inexpensive repair on your hands. The most likely problem is a dead or drained battery. If that's good, then your battery cables might be dirty or your starter may be going bad. Rule these things out before you spend any time troubleshooting other possibilities.

Dead Battery

Just because you have a dead battery today doesn’t necessarily mean that you have to go out and buy a new one. Many batteries lose their charge or go dead because of an outside power drain.

It may have been something as simple as leaving the headlights or a dome light on. Either of these can drain your battery overnight. The good news is that you can recharge it and it will still hold a full charge.

If you have a battery tester that can measure cranking amps, test your battery to see if it's weak. If the tester shows a weak battery, you'll have to replace it. If you don't have a battery tester, you can still see if the battery is good by jump-starting the car. Drive or run your car for about an hour or so, turn it off, and then restart it. If it starts, the battery is good. If it doesn't and you need to jumpstart it again, drive it to the nearest automotive store and buy a new battery.

Dirty Cables

Another thing that can stop your car from turning over is a dirty starter cable. This is the thickest cable in your car’s electrical system and carries the most current. As such, it is also very susceptible to corrosion.

If your starter cable becomes corroded, it can be cleaned rather easily. Remove each end of the cables—one end is attached to the battery, and the other is attached to the starter—and clean the connections with a wire brush. Don't forget to also clean the battery posts at the same time.

Unfortunately, the same fate can befall your ground cables. A corroded or poorly connected ground cable can also prevent the car from starting. Clean ground wires and connections in the same manner.

Bad Starter

It is also possible that you have a bad starter. A starter can go bad slowly over time and there are some things that can indicate when it is ready to go. For instance, you may notice that it seems like the engine starts slower than normal in the morning or you may be able to hear the starter turning more slowly than usual when you turn the key. You may also find that one day your car fails to start, then starts perfectly for a few days in a row. Then it fails again.

Further Troubleshooting

If you checked the three big culprits and they didn't work, keep your cool. There are only a few parts in your starting system, and a little troubleshooting can help you figure out why it's not working.

Sometimes your engine does turn over but will not actually fire. The culprits in this instance can include everything from distributors to coils, fuel pumps to fuel filters, spark plugs to plug wires. In this case, it might be worth it to drop the car off for a session with the professionals. But if troubleshooting is your passion, this is your dream problem. Go for it.

Electrical No-Start Problems

With the battery and the starter eliminated, it's time to work your way through the car. The best place to begin is with the electrical system.

Check Your Fuses: Only a few cars have a fuse associated with the starting system. However, before you go monkeying around with everything else, check your fuses to be sure it's not that simple.

Bad Ignition Switch: If your battery checks out, but the starter is still silent, it might be a faulty ignition switch. Turn the key to the "On" position, not all the way to start, and check the following:

  • If the red warning lights on your dash don't light up and your battery connections are clean, the ignition switch is bad.
  • If the red warning lights do light up, turn the key to the start position. In most cars, the dash warning lights should turn off at this key position. If you're not sure, turn on the headlights. When you try to start the car, the lights should either dim considerably or turn off completely. If they do, your ignition switch should be good. If not, the switch will need to be replaced.

Bad Starter Connection: Corrosion can keep your battery from connecting. It can also affect any electrical component, especially those that, like the starter, are exposed to the elements.

If you have someone to help you, you can test the starter connection by holding a circuit tester lead on the wire that engages the starter. This is the smaller of the two wires connected to the starter. Have a friend turn the key and check the current. If you're getting current to the starter but it isn't spinning, you will need to replace it. Note: Be sure that no part of your body is near the moving parts of the engine—it could still start at any time! 

If your starter spins freely when you turn the key, the problem lies elsewhere. Now you can begin to check the other systems that could keep it from firing up.

Ignition System Troubleshooting

With the starter-related causes of your problem out of the way, we continue the search for why your car won't start. Spark is created by your car's ignition systemIgnition system troubleshooting isn't too difficult and the first thing to check is your coil.

  • Coil Testing: To properly test your ignition coil, you'll need a multimeter that can measure impedance. If you don't have a multimeter, there is an easier test you can perform using simple hand tools. Test your coil and, if it's bad, replace it.
  • Distributor Cap: It's not likely that your distributor cap is the issue, but on occasion (especially during wet weather) a faulty cap can keep your car from starting. Remove your distributor cap and check the inside for moisture. If there is even a drop or mist of water inside, wipe it out with a clean, dry cloth. Inspect the cap for cracks and replace it if necessary. Once it's dry, it should work.
  • Spark Plug Wire: The starting problem could also be due to a broken or shorting coil wire. Inspect the wire to see if there are any obvious cracks or splits, then test for continuity using a circuit tester.

Did your car start? If not, it's time to move on to possible fuel-related problems.

Fuel System Troubleshooting

If the starter is spinning and the sparks are flying, your problem has to be related to the fuel system. If your vehicle is fuel injected, there are a number of subsystems that could be the culprit. It will take some serious diagnostic work to figure it out, but there are some things you can check in the garage in an attempt to narrow it down. These could save you some money and avoid a trip to the repair shop. 

Electrical Connections: There are plenty of electrical connections in your fuel injection system. Each fuel injector has a connector on top. There are connections on the air side of the intake and on the cylinder heads. You should check every electrical connection you can find under the hood to be sure it's tight.

  • Fuel Pump and Relay: To check your fuel pump, you can do a fuel system pressure test if you have the equipment. Since most of us don't have that type of thing, check the electrical connections first. Test the positive side of the fuel pump for current with a circuit tester. Be sure the key is in the "On" position. If there's current, move on to the next step. If not, you should check the fuse. If the fuse is good, your problem is the fuel pump relay.
  • Fuel Filter: If the fuel pump is working properly and fuel is still not reaching the engine, the problem may be a clogged fuel filter. You should replace the fuel filter every 12,000 miles or so anyway, so if you suspect it could be clogged, go ahead and replace it.

The items above are things you can easily check yourself using everyday automotive tools. There are many other elements of your fuel injection system that require electronic diagnosis. Unless you are familiar with this and have the right equipment, it is best to leave this to the pros.

Other Issues That Might Prevent Your Car Starting

With the major systems checked out, there are a number of other things you can check to see why your car won't start.

  • Loose Starter: Loose starter bolts will cause it to dance around and wiggle, failing to turn the engine over.
  • Bad Injectors: A bad injector can throw the entire fuel system off and keep the engine from firing, especially when the engine is warm.
  • Faulty Cold Start Valve: A failed cold start valve will keep your car from starting when the engine is cold. Don't let the name fool you, it can even malfunction when it's warm.
  • Chipped Flywheel or Ring Gear: Your starter's gear connects with the gear teeth on your flywheel or ring gear (depending on the type of transmission). If one of these teeth becomes worn or chipped, the starter will spin. In this case, you'll hear loud screeches, scrapes, squeals, and grinding.
  • Bad Electronics: If your engine's main computer or any part of the system's electronics go bad, your car won't start. Unfortunately, you'll need to leave this type of diagnostic work to a qualified repair shop.