A car may face several problems in its lifetime. Some problems may be associated with the electric circuits whereas others may relate to the engine. Among the common car problems, car cranking but not starting is one of the most encountered one. However, what is engine cranking?
When you turn the key in the ignition switch or press the start/stop engine button, you will hear a cranking sound before the engine starts working. If you hear the crank and the engine doesn’t start, it means your battery is fine. That said, there may be engine problems.
Here’s a guide that will cover all the reasons why a car cranks but won’t start with the solutions to the problems.
POTENTIAL PROBLEMS WHY A CAR CRANKS BUT DOESN’T START
The problem of car cranking but not starting may arise due to the following reasons:
- Insufficient compression
- Bad Fuel Injectors
- Fuel pump failure
- Bad Spark plugs
- Crankshaft position sensor failure
- Other sensors (MAF, MAP, and EGR)
INSUFFICIENT COMPRESSION
The engine needs fuel, air, spark, and compression to generate power. When the car cranks but won’t start, the problem may lie in the compression. If there is a problematic compression, it means the gaskets and seals are leaking air. That said, it will disturb the compression ratio. Besides, the issue can arise mainly due to the following components’ failure:
- Burned valve
- Worn-out compression ring
- Blown gaskets
In this case, you can consult a professional technician who can test the engine compression and make the necessary repairs and replacements.
FUEL INJECTORS PROBLEM
When the fuel doesn’t reach the engine, you may face a problem where the engine cranks but doesnt start. After a certain period, the fuel injector may get corroded, dirty, or clogged. That said, these clogged fuel injectors will not supply the right amount of fuel to the engine cylinders resulting in a lean air-fuel mixture.
Besides, a bad fuel injector may cause a car to turn over but wont stay running. Therefore, you can check the fuel injectors by using a multimeter. If you find there is a problem with the fuel injector, you must replace it to achieve optimum car performance as a working fuel injection system has several benefits.
BAD FUEL PUMP
Another reason why your car cranks but won’t start is a bad fuel pump. It is not always necessary that you have faulty fuel injectors, it may be the bad fuel pump that doesn’t supply the right amount of fuel.
To find out if there is a fuel pump problem, check the flow with a fuel pressure gauge. If there is zero or negligible pressure, you need to replace the fuel pump. However, if there is low pressure, your car has a clogged fuel filter or a bad fuel pump. In either case, you need to replace the fuel filter or pump to get your vehicle running.
SPARK PLUGS AND IGNITION FAILURE
If the compression is fine and there is no problem with the fuel system, then you might have failed spark plugs or an ignition system. The ignition system consists of the following components:
- Spark plug and wires
- Ignition coil
- Distributor
- Ignition control module
When you turn the key in the ignition, the spark plugs burn the air-fuel mixture. However, worn-out or bad spark plugs can malfunction which causes the engine cranks but not start. When you check it with an onboard diagnostic (OBD) sensor and it shows the car diagnostic code ‘P0301’, the problem may be bad spark plugs, ignition control module, or distributor.
Although the modern spark plugs last more than 100,000 kilometres, they can still fail earlier due to high carbon buildup. Therefore, replacing spark plugs is a better option to resolve your problem.
BAD CRANKSHAFT POSITION SENSOR
Your car needs to spark plugs to ignite the air-fuel mixture at the correct timing. If there is early or delayed ignition of the air-fuel mixture, the problem may be a failed crankshaft position sensor. The car computers or electronic control unit (ECU) determines the spark timing.
Therefore, if the crankshaft position sensor malfunctions, ECU will not be able to determine the correct spark timing. It will result in car cranks but not starting. You can take your car to the technician or check it via an OBD sensor. If it shows the code P0330, you need to replace the crankshaft position sensor.
OTHER SENSORS AND COMPONENTS FAILURE
While the above-mentioned problems are the main reasons why a car cranks but won’t start, you may witness failure in different types of car sensors resulting in this problem. For instance, some sensors and components that may cause car cranking but not starting are as followed:
- Failed exhaust gas recirculation (EGR) valve
- Manifold air pressure (MAP) sensor failure
- Bad mass airflow (MAF) sensor
A bad MAF sensor, EGR valve, or MAP sensor may also result in other problems such as rough idling, bad fuel economy, and engine starting. However, if your car won’t crank, there may be a battery failure.
The above-mentioned were all the reasons why your car cranks but won’t start. Therefore, when buying a used car in the UAE, always check all the factors to avoid future problems. Schedule regular maintenance checks to avoid any sudden or major repairs.
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