During the intense heat of summer or the cold of winter, it can be incredibly frustrating when your car refuses to start.
Car troubles can throw off your entire schedule, and the unexpected repair costs can significantly impact your budget. If your car won’t start, the issue could be simple or more complex.
Unfortunately, there are many potential causes, but for DIY enthusiasts and handy individuals, it might be possible to identify and fix the problem, getting your car back on the road again.
If you choose to handle the repair yourself, it’s essential to carefully follow the instructions in your owner’s manual and take all necessary safety precautions.
Below are 10 common reasons your car might not start, along with suggestions for what to do about it.
Dead Starter Motor
The starter motor is responsible for engaging the flywheel at the rear of the engine.
It’s a 12-volt electric motor that is exposed to the elements, making it prone to corrosion. Additionally, after thousands of engine starts, the starter motor may fail due to wear and tear.
What to do about it:
Typically, the starter motor can be replaced, and your car will be up and running again. The cost of parts varies depending on your car’s make and model, with an average price of around $350.
Replacing the starter motor can take less than an hour on some vehicles, while others may require more time and specialized knowledge.
Spark Plug Issues
Spark plugs are responsible for igniting the air-fuel mixture inside the engine’s cylinders. If the spark plugs are faulty, causing an inconsistent spark, it can lead to engine misfires, reducing performance.
Common issues include cracked porcelain insulators and worn electrodes. If more than one spark plug is malfunctioning, your engine might not start.
What to do about it:
A diagnostic scan can help identify which cylinders are misfiring. It’s best to replace all the spark plugs at once. For most vehicles, replacing spark plugs is a simple and cost-effective repair.
Timing Belt Skipped or Broken
The timing belt connects the crankshaft to the camshaft(s), ensuring that the timing of the engine’s cycles is synchronized.
Since it’s made of rubber, the timing belt is prone to wear and can fail if it becomes saturated with oil. It may stretch and skip a cog, or it can completely break. For some engines, a broken timing belt can cause serious damage.
What to do about it:
Remove the engine cover to inspect the timing belt for any breaks or skipped teeth. If the belt is broken, use a borescope to check if the pistons or valves have been damaged.
Replacing the timing belt requires precise installation, and major repairs may be necessary if the engine has been affected.
No Spark from Ignition Coil
Ignition coils amplify electrical pulses and send them to the spark plugs, which in turn ignite the air-fuel mixture in the engine. If an ignition coil isn’t working, your engine might not start.
What to do about it:
To identify the issue, swap the ignition coils or use an ohmmeter to check the wiring. Installing a new ignition coil is typically an easier repair, though coils can be quite expensive.
Restricted Fuel Filter
The fuel filter plays a critical role in maintaining the engine’s fuel pressure. Over time, it can accumulate debris from the fuel tank and become clogged, preventing fuel pressure from building properly.
What to do about it:
If the fuel filter is serviceable, it can be replaced in a matter of minutes.
If the filter is located in the fuel tank as part of the fuel pump module, however, replacing it could take several hours.
Fuel Pump Shorted
If the fuel filter is not the issue and the engine still lacks fuel pressure, the problem could be with the fuel pump.
The fuel pump is an electrical component, so it may fail without warning. Without adequate fuel pressure, the engine won’t start.
What to do about it:
Modern fuel pumps are often located in the fuel tank. Start by checking the fuse and testing the fuel pressure at the engine. Also, check the electrical continuity at the fuel pump. If necessary, replace the fuel pump.
Dead Battery
Car batteries typically last between three to six years, after which they start losing their ability to hold a charge.
However, a dead battery might also indicate a problem with the charging system, such as a faulty alternator or corroded wiring.
What to do about it:
Jump-start the battery and check if the alternator is charging above 12 volts.
If the alternator isn’t functioning properly, replace it. If the battery cannot hold enough charge to start the car, replace it.
Mass Air Flow Sensor Fault
The mass air flow sensor (MAF) measures the amount of air entering the engine.
If the sensor is faulty, it will send incorrect readings, leading to an improper air-fuel mixture. The issue could be with the sensor itself or the connector.
What to do about it:
Perform a diagnostic scan to check for error codes related to the air-fuel mixture. Inspect the MAF sensor’s connector, ensuring it is seated correctly, and replace the sensor if necessary.
Ignition Cylinder Stuck
If the key won’t turn in the ignition, your car will not start. This could be due to the ignition cylinder or the steering column becoming jammed.
What to do about it:
Remove the ignition cylinder to see if it can rotate freely. If not, replace the ignition cylinder and have it reprogrammed with the car’s security system.
If the ignition cylinder isn’t the issue, the steering column will need to be replaced, which may require a new ignition cylinder or switch as well.
Faulty Security System
If your car starts but immediately stalls or won’t start at all, the issue might lie with the factory immobilizer or security system. While uncommon, this can happen.
What to do about it:
A flashing key icon or a security warning on the dashboard could indicate a problem. A diagnostic scan is needed to check for security-related error codes.
The issue could be caused by a faulty module, broken wiring, or the ignition switch. Fixing security system issues typically requires dealer-level equipment.
While some issues, like replacing the battery or changing the fuel filter, are simple enough, other problems, particularly in older cars, may warrant reconsidering whether it’s time to upgrade.
Instead of spending your time and money on endless repairs, you may find that selling or trading in your car is a better option.
