A well maintained car is unlikely to have starting issues, but then, there are those days when the unexpected does happen. There are a number of reasons why a car won’t start. Everything from the electrical system to the fuel system to the starter motor can be the problem.
Finding the root cause of an engine not starting can take needs careful diagnosis. Ignoring a hard starting issue can further damage the vehicle, which will result in a more expensive repair.
How the entire system works to get a car started and running:
In order to start an engine, it must be rotated at certain speed so that it starts to suck fuel and air into the cylinders, and then compress and ignite this fuel/air mixture.
The starter motor is an electric motor that turns the engine to get it started. The starter motor has a small pinion gear wheel that engages with a larger gear ring at the rim of the engine flywheel.
The starter motor draws the electric current it needs to run from the battery. The starter needs a heavy current and to avoid sparking a solenoid is used. The ignition switch operates the starter motor. When the ignition is turned on, current is fed to the solenoid and into the starter motor. Once the car engine starts and the key is released, the starter motor turns off.
Possible Root Causes for your car not starting:
- Faulty Starter Motor: Over time starter motors can wear out and start to malfunction. If this is the problem the starter will have to be replaced. If you can hear the engine cranking (turning), the problem is not the starter. If nothing happens when the key is turned the problem could be the starter, or if the engine cranks very slowly and the dash lights dim while it is cranking, the starter could be the culprit.
- Faulty Relay Wiring: The wiring between the battery and starter can become loose or broken which will prevent the starter motor from functioning. The wiring will need to be replaced or repaired.
- Low or Dead Battery: The starter motor needs voltage from the battery to operate. If the battery is low or failing it may not produce enough current for the starter motor to function. Charging or replacing the batter should resolve this problem.
- Loose Battery Terminals: It is also possible that the battery terminals have become corroded or loose. Cleaning and tightening the terminals and cables is recommended.
- Failing Solenoid: A failing solenoid is a common issue with the starter system and if the solenoid is going bad, the car will be difficult to start. The starter will need to be inspected to determine if the problem is the starter motor itself or the solenoid. A failing solenoid will need to be replaced.
- Failing Ignition Switch: Over time an ignition switch can start to fail and one of the most common symptoms is that the car is hard to start. If the ignition switch is hot to the touch this indicates an issue with the ignition switch wiring. A failing ignition switch will eventually stop working completely and will need to be replaced.
- Defective Fuel Pump: If the engine is not getting enough fuel, it will be hard, if not impossible to start. The fuel pump is responsible for pulling petrol or diesel from the tank to the injectors and if it is not delivering enough fuel the car will be difficult to start and eventually will not start at all.
- Worn Out Spark Plugs (Petrol Engines Only): Spark plugs create the spark which allows the vehicle to burn fuel. Fouled plugs are one of the most common reasons for a hard starting engine. As electrodes wear down, the voltage required to jump the gap to ignite the fuel increases. This can lead to prolonged cranking before the engine will start.
- Clogged Fuel Filter: A fuel filter that is clogged can make a vehicle very difficult to start. The fuel filter screens out contaminants and can become clogged over time. This will prevent the injectors from getting enough fuel, making the car hard to start.
- Contaminated Fuel: Fuel that has contaminants beyond acceptable limits will result in a car that is difficult and often impossible to start. Even if it does start, contaminated fuel can do serious damage to the engine. If contaminated fuel is suspected, the vehicle must be inspected immediately.