Reasons why your car starts then dies

Car Starts Then Dies – 10 Reasons Why it Can Happen

One of the most annoying issues you can have is when your car starts then dies repeatedly. It can give you all the signs that it’s going to work, but then it coughs out on you anyway.

It can be difficult to see the logic of why this engine dying issue can occur, but it’s important to remember that cars are extremely complicated pieces of engineering these days.

Modern cars rely on a lot of moving parts acting in synergy to perform their seemingly basic task of getting you from A to B.

As a result, there are lots of factors which could be the cause of your car starting and then dying on you.

See below list of top 10 reasons why your car starts then dies and check out my advice on how to diagnose and solve it so you can be on your way.

1. Ignition Issue or No Spark

Ignition issues are one of the most common reasons why your car starts then dies, and they can be in multiple forms.

Spark Plug Failure

The most obvious of these is a lack of spark due to a faulty spark plug now providing a spark to the fuel and air mixture in the cylinder. If you’ve not changed or even checked your spark plugs for many years and miles, this could well be the source of your issue.

Although, it’s worth being aware that your car should be able to run with one spark plug playing up, but it will misfire, and unless you’re very unlucky it’s unlikely that you will have multiple fail at the same time. Also, if there are multiple plugs out if the car has been sat for many years, for example, it may not be able to start at all.

Ignition Coil Failure

The more likely ignition issue when your car starts then dies is an ignition coil issue. Similar to spark plugs, if your car has coil-on-plug ignition and each spark plug has its own coil and one fails then the car is likely to continue to run.

If your car is an older vehicle then it quite possibly has one coil feeding power to each plug through HT leads then its quite possible that this is the source of your issue, it may well be traced back to the distributor cap and rotor arm which are known to wear over time. A simple visual inspection of these should reveal how likely they are to be the culprit.

If your car is not an older vehicle, and the plugs are fine but there’s still no spark, then the issue could be related to the wiring which feeds the signal to the ignition coils. It would be wise to check these connections for any corrosion which could be preventing current from being passed through.

2. Fuel Pump Failure

A very common reason for a car to start and then die would be the fuelling system. Most common among these would be a fuel pump failure.

Fuel pumps in cars tend to go completely forgotten until the point they have an issue. Generally, when they do have an issue, it’s one which stops the car from running altogether.

If your fuel pump is on the way out, you can get into a situation where the car starts then dies.

The fuel pump needs to provide constant pressure to the fuel-rail which feeds each injector with fuel, the injectors job is top spray a mist of atomised petrol into the cylinder to mix with the air ready for ignition.

Like lots of electronic motors, they can go wrong in a lot of different ways. They can weaken over time and cause misfires or rough running with engine lights, or they can stop pumping all together unexpectedly.

In this case, your fuel pump could be intermittent and give an initial burst of life when you switch your ignition on but be unable to maintain sufficient pressure for more than a moment.

A quick and easy way to check if your fuel pump is functioning is to put your key in the ignition, switch your car to on, just before the click to crank the engine over and listen out for a whirring noise. That noise of the car waking up is generally the fuel pump turning and providing pressure ready for the car to start.

You may notice a weaker sound than normal which can certainly be a sign of fuel pump failure.

Car MAF sensor which can go faulty.

3. Engine Control Unit (ECU) Issue

Modern cars use highly sophisticated computer systems to manage the engine’s running, and as cars live outside through all seasons, it’s not that unusual to find that the ECU computer can eventually fail.

A particularly common example is with BMW E36’s where the compartment that houses the ECU is accessed via the engine bay, and due to its positioning can become the victim of water ingress, which I’m sure you’d agree, cannot be good for a computer.

As its fairly unusual for the ECU to fail in a way which only causes the car to die after being started, look out for other unexpected behaviour from the car.

Usually, there is no fixing an ECU which has suffered the fate of water ingress, and the only option is to replace it. At which point you’re going to hope your car is still within warranty.

4. Immobiliser or Car Alarm Issue

A common culprit which can cause your car to start but not continue running for long is the security system.

This system tends to consist of a clever immobiliser which allows the car to recognise when a paired key is inserted into the ignition barrel.

When the computer doesn’t recognise the signal that the key is giving off, it can promptly shut the car’s engine off in the hope to prevent it from being stolen and driven away by a thief.

Make sure the battery in your key is not totally dead, if the remote central locking doesn’t work at close range then this is a clear a sign of a key battery issue.

Generally, it’s quite easy to replace the battery in a car key and you can look up the method for your key and find out exactly which battery you need to replace it with.

More modern car keys can often be charged using a mobile phone wireless charger too.

If your car is an older car from around the 1980s and has an aftermarket alarm and immobiliser system fitted to it, then I’d consider this as highly likely to be the cause of your problems.

Those old school immobiliser systems were intentionally designed to cause the car to switch off after a few moments of running in the hope that a thief would give up and leg it.

If your car alarm starts behaving strangely and going off unexpectedly, this can be tied in closely with the immobiliser and be a sign of an issue.

5. Blocked Fuel Filter

A blocked fuel filter can lead to an engine cutting out unexpectedly due to fuel starvation, in a similar way to a faulty fuel pump.

Fuel filters are commonly overlooked by owners and mechanics and it has been known for a car to never get a replacement fuel filter in its entire life.

Generally, modern fuels are quite clean but you can occasionally get a bad batch, and the particles in these build up in the filter over time to reduce the flow through it, eventually limiting it so much that the fuel pressure on the engine side of the fuel filter is greatly reduced and not sufficient to keep the car running.

That extra moment the fuel has to pressurise after you switch the car on but before you crank the engine can sometimes be enough for the car to start initially but it then uses the fuel faster than it can get through the filter causing it to die.

If your car has been sat for a very long time and the fuel has escaped from all of the fuel lines and evaporated, this can lead to a fuel filter blockage and the sludge left behind by the fuel can very quickly block a filter completely.

A clogged fuel filter can also lead on to a failed fuel pump as the pump has to work harder, so if you find either your fuel pump or filter to be the offending item, its wise to change the other as a matter of course.

6. Mass Air Flow (MAF) Sensor Issues

The MAF sensor or sometimes MAP sensor is a key electrical component which works to maintain the correct air to fuel ratio for your engine to run optimally.

The sensor measures the volume of air entering your intake and passes the data onto the ECU. The ECU then calculates how much fuel needs to be injected to create the perfect air-fuel mixture for efficient running.

If your MAF sensor is not functioning correctly it can lead to rough running and inconsistency, which can at worst lead to the engine not being able to run whatsoever.

When a car starts then dies, it can often indicate that MAF is the problem. Before you crank a car over to start it, there is no air flowing into the intake for the MAF sensor to measure, thus the ECU has a default start-up sequence which can get the car to fire and start turning over consistently and providing data to the sensors.

If the MAF fails or becomes intermittent the car should crank and start but once it’s started and the readings from the MAF are interpreted by the computer, the air/fuel ratio can become very wrong all of a sudden and cause the car to die.

A nice way to check if this is your problem is to open the bonnet (or hood) and unplug your MAF sensor. The MAF is usually located on the intake pipe after the filter housing with a connector plugged in.

Once unplugged, attempt to start the car, if the car behaves exactly the same as when it’s plugged in and conks out shortly after being started, it could indicate a completely failed MAF sensor.

7. Car Battery or Bad Earth Issue

If the battery was flat you wouldn’t expect your car to fire up in the first place, so if it cranks strongly and fires up on the button, then you can generally rule a weak battery out of the equation.

However, if your car starts then dies, it could still be closely related to your electrical system and battery.

Your car’s battery is earthed or grounded to the chassis or car body, and if this connection becomes weak it can cause a lot of intermittent issues that can drive you crazy.

One of the common issues caused by a bad ground connection is the car dying after being started as the ignition system on the car is highly dependent on a solid and consistent electrical current.

When the car is not running the contact can be good, but when the car is running, the heat and vibration can cause an earth connection to become very slightly intermittent as it moves around resulting in haywire behaviour and the car dying.

Without the earth connection, the power sent to the electrical components in the car can be greatly reduced and too low for them to operate effectively.

To rule this one out, get a set of jumper cables and connect just the negative cable to the negative battery terminal, and the other end to the exposed metal on the car’s engine or body.

If the car is able to start and continue running indefinitely with this connected, you will have found your problem.

Ground connections can often become corroded, or loose, find the ground and clean it up with a wire brush, tighten it down or replace if its got rust issues.

8. Very Low or No Fuel

This one may seem obvious but being very low of fuel can be another cause of your engine cutting out.

Especially with older cars, it’s been known for the fuel gauge to become intermittent and no longer provide an accurate reading.

When this happens, you can lose control of how much fuel is in the car at any one time and eventually get caught out by having none unexpectedly.

As a matter of course, my advice would be to use the trip gauge on the car to measure your driven distance between fill-ups and observe how far you generally get on a tank, doing this will mean you never end up dangerously low on fuel unexpectedly.

If you think this might be the cause of your problems, get yourself a jerrycan and top your fuel up to see if the issue persists.

Car air filter where there can be potential blockages.

9. A Blocked Exhaust Pipe or A Blocked Air Filter

I’ve combined these two together as they are both effectively the passage of air through the engine that can lead to your running problems.

If your car starts then dies, it could be down to a clogged air filter preventing your engine from being able to draw in enough air to mix with the fuel for effective combustion.

If you are aware of driving through an environment such a sandstorm or a snow blizzard then it is certainly advisable to remove your air filter and bat it out regularly. If your car has not had a replacement air filter for many years this can also result in weak airflow preventing your engine from being able to maintain its running.

A symptom of this problem coming on would be the car struggling to climb up the rev range and increase engine speed no matter how hard you pin down the throttle peddle.

More difficult to confirm but equally likely are issues on the exhaust side.

Air needs to be able to flow freely out of the engine just as it needs to be able to enter. Once combustion has occurred, the next stroke of the piston pushes the spent air out through the exhaust valve into the exhaust manifold and down the exhaust pipe to exit to open air.

Rust can be the real killer for exhaust pipes and they have been known to rust considerably from the inside and restrict airflow, the only solution to this is to replace the exhaust pipe.

Modern cars have multiple components involved with the exhaust system which can pose an issue, the main suspect I’d have in a case like this is the catalytic converter.

This component of an exhaust pipe is effectively a fine honeycomb of material with infused precious metals that work to reduce the noxious and polluting gasses from the exhaust fumes.

It’s not too uncommon for the honeycomb elements in catalytic converters to break down or clog up, preventing the passage of exhaust gasses. If they clog up much then they can end up becoming literally glowing red hot which you can see if you peer under the car.

This, of course, leads to the honeycomb melting down and completely blocking the exhaust pipe, causing a situation where your car starts then dies.

10. Carburettor Problems

If your car is an older car from the early 1980s or before, then there’s a good chance that it uses a carburettor system to get fuel into the engine.

If I was writing this article 30 years ago, I’d have listed this as the number 1 likely cause of your car dying shortly after firing up.

Classic car with carburettor fuelling system.

Carburettors are complex mechanical systems which work completely independently of any electronics. As a result, they need to be expertly set up to provide the correct mixture of fuel for the air entering the engine at any given time.

To do this, a carburettor has a small fuel reservoir within and a float which keeps the fuel level consistent.

The air entering the cylinder and passes through the carb and picks up fuel from the jets as it flows through mixing it together.

At this point, if you have a car which has carburettors for its fuelling system then its likely to be a classic rather than a daily driver.

If you’ve not driven the car in a long time, then the fuel can evaporate from the system leaving behind deposits that prevent the carb from performing optimally and providing the engine with adequate fuel and air mixture, this can then lead on to the car starting but then dying.

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