Why a car won’t start troubleshooting tips


There are many things that can go wrong with your car, but no need to worry, there is a solution for almost every problem.
Of course, you can call your local automobile association or a towing service and have your car towed to a local repair shop, but if you want to know why it doesn’t start, read further. The process that goes on from the moment you put the key into the ignition to the point where the engine is running involves a few steps. Once you know at which step things go wrong, you will have a better idea why your car won’t start and what to do. If your car has a push button start system.

What to check first

If the car won’t start, check the basic things first:
• Is the battery OK? Read the next paragraph how to check the battery.
• If the car doesn’t start with the automatic transmission in “Park,” does it start in “Neutral”? Sometimes a car won’t start in “Park” but starts in “Neutral” because of a problem with a neutral safety switch.

• Are the battery cables tight and not corroded?
• Do you think Is there enough fuel in the tank? It’s a common situation when the fuel gauge isn’t working properly and the car runs out of fuel with the fuel gauge still showing some fuel left. There is no way to check the fuel level other that the fuel gauge. But you can estimate how long did you drive since the last fill up.

• Is the “Security” or key-shaped light in the instrument panel stays on or blinking? Read below about the security light.
• Does your car have an anti-theft system that for some reason doesn’t allow the car to be started?


How to check the battery

A discharged or dead battery is one of the possible reasons for a car not to start. Sometimes we just forget to turn off the dome light or something else, or it could be some faulty component of the vehicle electrical system that drains the battery down. Sometimes, if the battery is old, it could just die one day, even if the day before it was OK. In either case, if the battery is low on charge, it won’t have enough power to turn over the engine: you may hear some clicking noise or the starter may turn very slow when attempting to start the engine.

Here is a simple way to check if the battery is discharged:
Turn the windshield wipers on. If they move very slow, much slower than usual, the battery is probably low on charge. Look at the dome light. Does If it gets very dim when you try to start or when you turn the wipers on, the battery is most likely discharged.

If the battery is relatively new, it can be recharged. One way to do this is to jump start your car and let the engine run for a while to re-charge the battery. Read below about jump starting. One thing to be aware: if the battery is more than 4-5 years old, it might be completely dead, so it won’t take charge and the car will not restart again after you shut it off. In this case, you may need a new battery. A problem with the vehicle’s charging system can also cause the battery not to re-charge.

The key won’t turn in the ignition

If the key won’t turn in the ignition, it could be for a couple of reasons: Often this happens when the steering is locked by the ignition lock with the front wheels turned aside (e.g. when parking on a hill) or when one of the front wheels is pushed against something (e.g. curb stone). In this case, try turning the steering wheel left and right while gently jiggling the ignition key – this might help to release the steering lock.
Another possibility is that there is a problem with the ignition lock or the key itself. This happens; the key and the lock mechanism wear over time. Try to use a spare key. If nothing works, your local dealer is the best place to call.

No lights on the instrument panel

If you turn the ignition on and no lights come on at the instrument panel means that there is no power coming from the battery. It could be a dead battery or often a bad ignition switch could cause this. Turn the headlights on, if they work, means the battery has power, so the problem could be with the ignition switch or wiring between the ignition switch and battery.

If no lights coming on in the dash and no other electrical consumers work, the battery could be completely dead or there is no connection between the battery and the vehicle electrical system. Check if the battery terminals look tight. If the battery is completely dead, jump starting might help.

The “check engine” light does not come on

When you turn the ignition ON before starting the car, the “Check engine” light is supposed to come on indicating that the engine computer (also could be called ECM, PCM, or ECU) is powered on. If the “Check engine” light does not come with the ignition ON, it’s possible that there is no power coming to the engine computer (e.g., due to a broken wire, faulty main relay, burnt fuse, etc.) or that there is a problem with the engine computer itself.

“Security” or Key-shaped light stays on or flashes on the dashboard

Many cars are equipped with an immobilizer or a security system that allows the engine to start only if the correct key is used. You can find more information about the immobilizer in your owner’s manual.
Basically it means that an ignition key has a chip inside with the security code. When you insert it into the ignition, a sensor for the security system reads the code. Normally when you turn the ignition on, you would see a “Security” light to come on for a short time and then it would come off. That would mean that the code in the ignition key is correct and the car is allowed to start.

If when you turn the ignition ON, the “Security” light stays on or flashing means that your car security system does not recognize the key or there is some problem with some part of the security system itself.
Some GM cars, for example, had a problem with the security system sensor located at the ignition lock. Sometimes, the key is just need to be reprogrammed. You can find the information how to re-program the key in your owner’s manual or just Google it. In some cases there is a simple procedure to re-learn the key that fixes this problem. You also can try the spare key and if nothing works, your dealer is the place to call. You dealer can check your immobilizer and reprogram the ignition keys if needed.

The engine cranks progressively slower, then just clicks

If the engine cranks slower and slower until it just clicks, means the starter motor doesn’t have enough power to turn over the engine. This problem should be fairly easy to diagnose, as there are just two cables (positive and negative) to deliver the electric current from the battery to the starter motor. Once again, a very weak battery is the most common problem in this case. A bad starter motor also can cause this issue. And of course, a poor connection or corrosion at the battery terminals or bad battery cables can also cause these symptoms. If the battery is very old, you might want to start with replacing the battery; a new battery is not very expensive.

Problems with the engine computer (PCM) or PCM circuits

A faulty engine computer or PCM is rare, but some cars had known issues with it, including older Nissan Sentra and Ford Escape models. We had seen problems where the PCM circuit or fuse were shorted after boosting a dead car battery. In some cars, you can tell that the PCM is not powered by watching the “Check Engine” icon when the ignition is turned on: when the PCM is not powered, the icon does not illuminate. In some older Mazda cars, the corroded wire at the PCM fuse in the fuse box is known to cause a no-start issue. The PCM is an expensive part, however it is usually covered by an emission warranty (8 years or 80,000 miles).

Engine is flooded

This problem is common, especially in high-mileage vehicles. A car stars then stalls out and doesn’t re-start again. Mazda RX-8 was famous for flooded engine. What happens, the excess gasoline fouls spark plugs and washes of the oil from the piston rings (or rotor seals in RX-8) reducing the compression. Your mechanic may advise to replace or at least remove and dry out the spark plugs and re-charge the battery. Once spark plugs are removed, the excess gasoline dries out. With new spark plugs and re-charged battery, the engine usually starts well. For the RX-8 there is a special de-flooding procedure that you can find on one of the RX-8 forums.

Bad fuel pump or fuel pump relay

This problem is also common in high-mileage cars. One day, a fuel pump just stops working and the car doesn’t start. When you take your vehicle to the repair shop, your mechanic will need to run a few tests. Typically they test the fuel pressure among other things and check the fuel pump electric circuit and the relay. A bad fuel pump or main relay is actually common in some Honda, BMW and other vehicles. Replacing the relay is not expensive. If your fuel pump is failed, we recommend to trust this job to a qualified technician, as in many cars the fuel pump is installed inside the gas tank.


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