Home Diagnosis and TroubleshootingEngine Problems My Car Starts Sometimes And Sometimes It Doesn’t – What’s Wrong?

My Car Starts Sometimes And Sometimes It Doesn’t – What’s Wrong?

by Jordan Harris
My Car Starts Sometimes And Sometimes It Doesn't

Are you starting to experience a strange problem? My car starts sometimes and sometimes it doesn’t? This problem can be a frustrating thing to deal with. But we are going to help you out in tackling it quickly and effectively.

Having a problem like this can be frustrating as we mentioned. Meaning that you can have your car once started and working fine but you turn off the engine and the car doesn’t want to start again. The confusing thing I must admit. Luckily there is a way around this problem and it can be tackled quickly and effectively.

The key to tackling this problem is to learn how to troubleshoot problems. But how you can do that? Well, you can do that by learning how the components work and how some components are affecting other parts of your car. Knowing this stuff will be a lifesaver for you since you will be able to tell why this problem is happening and understand the root of the cause quickly. And we are going to help you out with that.

First, we are going to elaborate on the problem of my car starts sometimes and sometimes it doesn’t. Then we will cover all the possible reasons why this problem happens from all of the different aspects. Electrical, fuel delivery, and also possible engine damage. Then we will learn how to fix this problem and what would be the grand total for fixing this thing. So, if you want to learn more, follow along.

My Car Starts Sometimes And Sometimes It Doesn’t… Why?

Now let’s elaborate more on this problem my car starts sometimes and sometimes it doesn’t. Since it is a strange problem. As we all know, when the car starts, it should remain turned on until you turn it off. That is, sometimes the second crank over can fail altogether.

Whenever a problem like this happens can mean that there is something wrong with a certain component. More on that later when we will cover the possibilities. But the thing is that whenever you have a problem like this, it is likely caused by a faulty component that is nearing the end of its lifespan.

As we all know, car components often last for a couple of years, and then they fail. Whenever they fail, they will start to develop these strange symptoms that will make you all confused and full of questions.

My Car Starts Sometimes And Sometimes It Doesn't

But you shouldn’t worry since this is a cause from a component that is failing. The important thing is that you are already here. Because the next step would be when the car will completely fail to start and you will be left out stranded on the side of the road. Yep, that’s right, whenever some of these components fail completely, you will be left beside the road calling for roadside assistance.

So, the good thing is that you are here where we will elaborate on the reasons why my car starts sometimes and sometimes it doesn’t. Knowing the reasons will help you jump to a conclusion quicker and determine what is happening with your vehicle. But more on the reasons in the following chapters where we will elaborate on these things in detail.

Reasons For My Car Sometimes Starts And Sometimes It Doesn’t

We elaborated briefly on the problem of why my car start sometimes and sometimes it doesn’t. Now let’s learn the reasons why this problem happens in the first place.

As you know, knowing the reasons why this problem happens in the first place is going to help you out find a proper solution much sooner and you will avoid being left stranded on the side of the road.

My Car Starts Sometimes And Sometimes It Doesn't

It is worth noting that there are three possibilities for when my car starts sometimes and sometimes it doesn’t. These causes can be electrical problems, the second possibility can be because of bad fuel delivery and the third reason can be found in the engine and its internals. In the following chapters, we are going to elaborate on all three aspects of why my car starts and sometimes it doesn’t happen. So, let’s get into it.

1. Electrical Problems – My Car Starts Sometimes And Sometimes It Doesn’t

When it comes to the problem of why my car starts and sometimes it doesn’t it is worth starting from the electrical problems.

These problems are likely the most common causes for this problem happening on your car since everything when it comes to the ignition is electronically controlled. Meaning that you have to have your electric components in check so the engine would start.

When it comes to these components it is worth noting that there are sensors as well as other different components that make your car crank and start. Having one of these components not working right will make my car starts sometimes and sometimes it doesn’t occur. So, which are these components? Let’s elaborate.

Crankshaft Positioning Sensor

The first thing that can cause my car starts sometimes and sometimes it doesn’t is the crankshaft positioning sensor. This sensor plays a key role in starting the vehicle. If the sensor is not working properly, your car will continuously crank until the battery dies.

Sometimes it can even start eventually after a lot of cranking. But the damage to the battery will be done and it is highly likely that you are going to need a new battery after replacing this sensor.

Unfortunately, this problem cannot be diagnosed without an OBD2 scanner tool. Since you cannot tell if the sensor that checks the position of the crankshaft is bad without this tool. But if the car loves to crank and start after a lot of cranking, then this is probably the reason for the problem of my car starts sometimes and sometimes it doesn’t. If you don’t suspect on the sensor, move on to the other probable reasons.

Bad Engine Ignition Coils

The second probable cause for my car starts sometimes and sometimes it doesn’t is probably the engine coil or coils that reached the end of their lifespan.

As you know, on modern engines there is one coil per cylinder. This coil is distributing the electricity to the spark plugs. Meaning that these coils are really essential components in every internal combustion engine. Without them being in proper working order, your engine would pretty much struggle to start and keep on working.

Try to remove one and start your engine. It will just not want to start. Ignition coils are essential. And if you have an engine like a straight-4, a single coil can prevent your engine from working properly.

The coils are also diagnosed with a help of an OBD2 scanner tool. With this tool, you will be able to scan the car for codes and replace the coils that are not working right. Then this will probably fix my car starts sometimes and sometimes it doesn’t from happening in the near future. If not, move on to the next probable reason.

Bad Spark Plugs

Bad spark plugs are the third major reason why you might experience the problem of my car starts sometimes and sometimes it doesn’t. Why is this the case? Well, this is the case because the spark plugs are one of the most essential components that allow your car to start.

If the spark plugs are fouled and damaged or old, then you might experience a problem like my car starts sometimes and sometimes it doesn’t.

This is happening because the spark plugs are working at their limit. Meaning that sometimes they can make enough power and sometimes they cannot get that amount of electricity and make the engine crank a lot before it starts.

The best thing is to inspect them and see if they have oil or if they smell like gas and whether they have some other damage. Replacing them will be a good idea and the first thing that you can do for fixing this problem with my car starts sometimes and sometimes it doesn’t.

Bad Battery

A bad car battery can also make you notice my car starts sometimes and sometimes it doesn’t. Why is this the case? Well, this is the case because the car battery does not have the power needed for the car to start.

My Car Starts Sometimes And Sometimes It Doesn't

Most cars require 12V of power to start. So, if the battery has 8V and one or more dead cells, means that the car will not be able to start on the first try. This problem with my car starts sometimes and sometimes it doesn’t is a good way to check the health of your car battery and make sure that it works well and delivers enough juice to the spark plugs.

Starter Motor Doesn’t Work Well

Another thing that can cause my car starts sometimes and sometimes it doesn’t is the starter motor. As you know there is a starter motor that spins when you crank the car. This starter motor turns over the engine. Sometimes unfortunately this motor can fail and make the engine fail to start from the first try.

You will need to continuously crank it in order to be able to start the car. So, if you suspect on the motor itself this might be the probable cause. Since the solenoid on the motor can either work or not. There is nothing in the middle. So, the most likely outcome is that the starter motor itself is bad and is causing my car starts sometimes and sometimes it doesn’t.

2. Fuel Delivery Problems – My Car Starts Sometimes And Sometimes It Doesn’t

We covered the electrical side of why this problem of my car starts sometimes and sometimes it doesn’t and now let’s focus on another aspect. And that is the fuel delivery system.

As you know, every component in the fuel delivery system has to perform well for your car to start from the first try. If the components are not performing well, you will have the problem of my car starts sometimes and sometimes it doesn’t. So, what are the possibilities? Let’s see.

Clogged Fuel Filter

A clogged fuel filter is probably one of the primary suspects of this problem of my car starts sometimes and sometimes it doesn’t. So, why is this the case?

Well, this is the only logical explanation. As you know, the fuel has to be pushed from the fuel pump through the filter and into the fuel lines to start the car. So, if there is an obstruction like in this case is the clogged fuel filter, the car will not be able to start sometimes.

Fuel filter clogged dirty replacement

Starting the engine will be extremely difficult until the fuel pump builds enough pressure to push on force the fuel that is obstructed by the clogged fuel filter. This action could be damaging for the fuel pump and you can make your fuel pump fail if you run your car like this for long periods. The fuel pump has its limits and it will eventually fail.

So whenever you notice the problem with my car starts sometimes and sometimes it doesn’t. It is important to act quickly and try to replace the filter if it wasn’t replaced. As you probably know, these filters should be replaced every 30,000 miles. If you delay it, problems like this will happen.

Bad Injectors

Bad injectors can also make my car starts sometimes and sometimes it doesn’t. As you know, the injectors are the components that are in charge of injecting fuel into the engine.

They, like other components in your car, can fail or develop issues. One of these issues is probably the bad fuel dispersion. Fuel injectors should inject fuel at the right pressure and should perform this work well for the engine to be able to start.

Especially direct injection engines that are extremely sensitive to fuel. They can get damaged and cause bad fuel delivery. They are also quite expensive to replace. You probably don’t want the cause of my car starts sometimes and sometimes it doesn’t to be the injectors in your direct injection system.

This problem can only be diagnosed with computer diagnostics. If you have an OBD2 scanner by your hand, you can use this scanner to scan the car for codes and learn which of the injectors is the root cause of this issue in your car. Then if an injector is faulty, replace it with a new one.

3. Engine Problems – My Car Starts Sometimes And Sometimes It Doesn’t

We covered the possibilities from the electrical perspective and also from the fuel delivery perspective. Now let’s focus on the problem from the engine side. Although there could be only one problem.

This problem is a major one. This problem can make the issue of my car starts sometimes and sometimes it doesn’t and also show some other symptoms like loss of power and inability for the engine to keep working properly. In the following chapter, we are going to elaborate on the problem in depth.

Low Engine Compression

This is probably one of the things that no car owner wants to experience. Especially when he has my car starts sometimes and sometimes doesn’t.

Low compression means that your engine is slowly but surely dying. The engine is struggling to start and also struggling to keep working right. It is down on power and has really low pulling power. The power basically is diminished.

When this symptom happens it is a clear sign for you to do a compression test. Don’t lose your time with changing a lot of expensive parts when the core of the problem of my car starts sometimes and sometimes it doesn’t is in the engine itself.

Just get one of these cheap compression testers and test the engine for compression. Depending on the compression ratio of the engine you should grade the performance of the test. But if the average compression is above 90 and goes up to 100, then the cylinder probably has a good compression to work. If the compression numbers are lower than 90, the engine needs to be opened and checked.

If there are some valve issues, you should fix them. And if the problem is deeper. Then it’s a much better option to replace the engine with a new one and call it a day. That’s for sure going to fix your problem with my car starts sometimes and sometimes it doesn’t.

How To Fix The Problem With My Car Starts Sometimes And Sometimes It Doesn’t

But how you can fix the problem of my car starts sometimes and sometimes it doesn’t? The answer depends much on the root cause of the problem.

The easiest things that you can make are replacing the spark plugs, the battery, and the fuel filter. These are the components that should be replaced anyway after a couple of years since they age and can cause problems like these to happen in the first place. Also, it will not cost you more than $200 to sort these items and replace them with brand new ones.

If the problem still is not sorted out and my car starts sometimes and sometimes it doesn’t, it means that you need to dive deeper into diagnosing the issue. Get a compression tester and an OBD2 scanner tool.

First, measure the compression to be sure that your engine is good. If the engine fails the compression test, it means that here lies the problem. The engine is probably near the end of its lifetime.

If the compression is good, then scan the car for codes with the OBD2 scanner tool. See if there are codes produced by the car and if there are. Clear them off and scan the car again. Then read the codes and learn from them. If there are errors that indicate some coil issues or fuel injection problems then follow the codes and learn for the possible solutions online on forums.

If this is too much of a hassle for you, just take your car to the local mechanic’s shop and let them sort out the issue. This is the simplest that it can get. And if you don’t want to complicate things, this might be the way to go.

Cost To Fix This Starting Problem

Now let’s see what is the cost to fix my car starts sometimes and sometimes it doesn’t. In the best scenario, let’s say your car only needs a small tune-up with new spark plugs and a battery. You can expect to pay about $200 or slightly more than this. Nothing major.

If there is a bigger problem like a problem with coils or other electrical components like the starter, you can pay more to sort this issue. Sorting this will probably going to cost you about $500 or even less.

In the worst case, if the engine has a lot of blowby and doesn’t have compression. You can expect to pay from $1,000 for a valve job. Up to $5,000 for a new engine. That’s why having a low compression is something that you don’t want to have. Even a rebuild will cost you more than $2,000. This is another good option if you want to get the engine sorted and not replace it.

Can I Continue Driving Like This With This Problem?

The short answer is if can you drive with my car starts sometimes and sometimes it doesn’t depend on the problem that you have.

For example, if this is a minor thing, you might get away with it and continue driving. But when this component that is affected fails completely, the car will be stuck and you will not be able to start the engine. Meaning that your driving for today is done and the problem will require solving before you continue driving the car.

Facts: Troubleshooting Intermittent Car Start Issues

  • Intermittent car start issues, where a car starts sometimes and sometimes it doesn’t, are common problems that car owners face.
  • The root cause of this issue can come from various vehicle parts, including the battery, sensor, fuel system, engine, and others.
  • To diagnose the problem, it is essential to understand how each component works and affects each other.
  • Some common causes of this issue include a faulty crankshaft positioning sensor, insufficient battery voltage, issues with wires and cables, a faulty starter motor or solenoid, bad or exhausted engine ignition coils, problems related to the fuel filter, and low engine compression.
  • To troubleshoot this issue, you can recharge or replace a bad battery, clean dirty air filters, and battery terminals, replace damaged or corroded parts, do a compression test for engine issues, and use an OBD2 scanner to diagnose fuel system issues.
  • Replacing some components, such as spark plugs, batteries, or electrical parts, may cost around $200 to $500, while more extensive repairs, such as valve-related or engine rebuild or replacement, may cost around $1,000 to $5,000.
  • Signs of a bad starter include strange noises like grinding, whirring, or high-pitched sounds, while a bad fuel pump may cause difficulty starting, whining sounds, sputtering and stalling, or surging and power loss.
  • To determine whether it’s a problem with the starter or alternator, you can check the battery connections, listen for a clicking sound when turning on the key, or hit the starter lightly with a hammer and try starting the car again.
  • To prevent intermittent car start issues, it’s essential to keep the battery power at a high level, maintain cleanliness in all parts, and avoid corrosion.
  • If you don’t have enough knowledge about automobiles, it’s best to bring your car to a repair shop for professional diagnosis and repair.

Conclusion To My Car Starts Sometimes And Sometimes It Doesn’t

In this article, we have covered quite a bit when it comes to the problem of my car starts sometimes and sometimes it doesn’t. We learned all the possible causes from three different perspectives.

As we concluded, there could be electrical problems that will prevent your car from starting. There could be fuel injection-related issues like clogged filters or damaged injectors and there could be simply bad engine compression.

When the compression inside of the engine is poor, the engine simply struggles and it is quite difficult to start and continue running. So, depending on the problem, you should start looking for a solution. Most of the causes are relatively cheap to fix and will require little mechanical knowledge to sort them out.

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