While turning the car key in the ignition, sometimes, it sounds like it is just about to start but nothing turns over. You may go frustrated and turn the key repeatedly in the hope that engine will start but unfortunately nothing goes right unless you figure out the actual reason.
There are majorly eight reasons associated with this issue where the car engine cranks but doesn’t start. All of these reasons are directly or indirectly connected with any of these three things – a spark, fuel, and compression.
Let’s break down these aspects to have deep understanding!
Causes of a Car Engine Cranks Won’t Start
1. Vehicle Has No Fuel
Having no fuel in the fuel tank of your vehicle is a very obvious reason which can cause your vehicle to crank but not start at all. So, if this issue happens to you, before doing any troubleshooting, make sure you check the fuel gauge and maintain an adequate amount of fuel required to run the vehicle.
2. Issues with the Battery
If you notice the car engine cranks too slow, a weak or partially charged battery can be the culprit.
Because the battery is low on power that’s why it causes the car engine to crank but it doesn’t start.
In regard to battery, sometimes, there is corrosion on the terminals of the battery or the terminals are too loose which also adds to this problem. The battery issues are easy to resolve and in most cases, the jump start works.
3. Bad Fuel Pump
A bad fuel pump meaning a weak or corroded fuel pump may cause problems in supplying fuel to the vehicle’s engine. We know that to make an engine work properly, it requires fuel.
Without fuel, the engine may crank but will not start. To test a fuel pump, turn on the ignition, if you hear a “Whirring” sound, it means the fuel pump is working and if there is no such sound means the fuel pump is faulty.
In this scenario, the only solution is to replace the fuel pump.
4. Frozen Fuel Line
A frozen fuel line may also lead to the same problem where the engine cranks but doesn’t start. Why this happens is only because a frozen fuel line prevents fuel from getting into the combustion chamber which results in no start at all.
This happens only during the coldest months of the year when the water vapor present in the fuel line gets freeze and restricts the supply of fuel. The solution to this problem is that don’t leave your vehicle idle for a long period.
5. A Weak Starter Motor
As a weak starter motor would not be able to generate the amount of power needed to turn on the ignition system which will result in the same problem – the engine will crank with a lot of weird noises but will not start. If the starter motor is not replaced timely, gradually, the engine will stop cranking.
Therefore, when you’re sure that the problem is with the starter motor, it needs to be replaced sooner than later.
6. Faulty Spark Plug
A spark plug – small but mighty – plays a crucial role in starting up the engine. It is responsible for creating that initial spark required to ignite the air/fuel mixture which produces compression needed to start and run the vehicle.
If spark plugs are not working properly, the engine cannot start, results in a dreaded crank sound come out of the engine when you turn the key on and off.
Related Article: Symptoms of Bad Spark Plugs
7. Trouble With the Computer Sensors
There are sensors in modern vehicles – responsible for sending information to the engine for efficient working of the vehicle.
The two main sensors which directly affect the engine’s ability to start are the camshaft position sensor and the throttle position sensor. If any of these sensors stops performing properly, the engine will have an issue with starting up.
8. Security System Malfunction
You will find a security system in almost all of the modern vehicles, designed to protect your vehicle from theft and vandalism. This security or alarm system is connected with a few sensors and when these sensors start malfunctioning, they affect the working of the ignition system which sometimes does not let the engine start.
If you have checked all of the above reasons and you found everything working fine then must get checked your security system installed in the vehicle.
How to Fix a Car That Won’t Start But Cranks
First Step – Check the Fuses
First of all check for blown fuses as it can cause a severe electrical problem in your vehicle that will restrict your vehicle from starting up. With the help of a test light, you can easily locate the blown fuse. If there is any blown fuse, replace it and restart the engine.
If it still doesn’t start, move on to the second step.
Second Step – Check the Spark Plug
Locate the spark plugs and check them for any damage or bad gapping. If issue is with the spark plugs, replace them. But if spark plugs are in good condition, look for spark plug wires, the distributor, and the ignition coil.
First, check the ignition coil for spark. Using a spark tester, you can quickly find out whether the ignition coil has spark. If the ignition coil is generating spark, it means the problem lies either with the distributor or the wiring between these three components – ignition coil, distributor, and spark plugs. Replace them all.
Now if there is no spark issue and still, the engine is not starting up and only cranking, it means there is issue with the fuel supply.
Third Step – Check the Fuel Supply
To confirm whether the vehicle has an issue with the fuel supply, there is a quick method – spray a small quantity of starting fluid into the air intake hose. Now, try cranking the engine once again, if the car starts and runs for a few seconds and then again dies, it means the system is not getting a sufficient amount of fuel. It means the problem is either with the fuel pump, fuel filter, or fuel injectors.
The quickest method to check the fuel pump is to put your ear near the fuel tank and have an assistant turn the ignition key to the “on” position. The fuel pump should make an audible noise if it’s working properly. If there is no noise, it means there is problem with the fuel pump. Replace the fuel pump.
But if fuel pump is working properly, there could be a problem with the fuel filter. There might be a clogged fuel filter that is restricting the supply of fuel. Clean or unclogged the fuel filter and again turn the ignition key on and check whether the vehicle is able to start.
If the issue is not resolved, check the fuel injectors. The fuel injectors might be clogged, clean them and again test the vehicle, if the problem still persists.
Fourth Step – test the compression
If, after trying everything, the problem could not be resolved, then perform the last step that is testing the compression of the vehicle. Using a compression tester, you can quickly test the compression.
If there is low or no compression, it can lead to such issues where the engine cranks but doesn’t start. If the compression tester shows low or no compression, there could be a serious issue with the vehicle, and an expert can help you out with this. So take your vehicle to an expert mechanic.
We hope this quick guide has made you more informed about how to handle such issues related to the vehicle. This guide will surely save you time and money that you might have invested on repair from professionals.