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BMW 335i Not Starting

5 Reasons Why Your BMW 335i is Not Starting

When people buy a car from a luxury brand, they expect that they won’t face the same problems as they do with budget models. While the probability is lower, every car essentially faces the same type of problems from time to time. That is why we have made a post on what to do when your BMW 335i is not starting.

Whenever your BMW 335i is not starting, the problem is usually related to either the starter motor or the battery. If the starter motor isn’t functioning, then you have a few ways to start the car for the day. On the other hand, battery depletion may also be an issue preventing the car from starting. Apart from this, there are other issues you might want to look at including the fuel pump, sparkplugs, and even the alternator.

All these issues and their possible fixes will be discussed in this article.


jump leads on battery
Car Battery | Image Credits: Pixabay

First things first, the most common reason that your BMW 335i is not starting is that your battery is malfunctioning. There may be several possible root causes for this, but usually, it is because your battery has a low charge or is depleted. Your battery should have at least 11-12V with the engine off for the car to start. A multimeter can verify this easily if you connect it to the battery terminals.

You should get a warning regarding this on your dashboard if the voltage starts to drop around this point. If you have the time, you can use an external charger to charge the battery overnight. Alternatively, if you need a quick solution, you can jump-start the car with the help of another one.

Other problems may include corroded battery terminals, blown battery wire fuses, or even loose wires. These problems are a case of simple maintenance. Thus, you might want to open the hood of your car and check what is the condition of the battery underneath. Tighten the wires and brush off the corrosion with a wire brush if needed. If the car still doesn’t start, you may want to replace the battery wires and try once again.

Finally, the worst-case scenario is that your battery has reached the end of its life. As the battery ages, its capacity deteriorates. After a point, the available capacity is no longer sufficient to power the various systems of the car. Other problems like internal short-circuiting or dendrite formation may also lead to a dead battery like this. The only solution is to replace the battery at such times.


Photo by Jorge César on Unsplash

The alternator is responsible for charging the battery. Thus, if there are problems with the alternator, the battery doesn’t get charged properly. As a result, you have a car that doesn’t start the next morning. The reason for alternator failure is generally some liquids getting into it or due to wear after a lot of use. The way to solve this is unfortunately to replace the entire alternator.

Starter motor

starter motor
Starter Motor | Image Credits: Pixabay

A gasoline engine cannot function at zero speed (rpm). Thus, the starter motor does the job of getting it to a point from which it can pick up. It is powered by the battery at the start of operation. However, sometimes the starter motor does not function as required. Either the starter motor does not get engaged or due to excess wear, it can’t bring the engine to the required speed.

The former problem can be identified if you don’t even hear the whirring sound when you start the engine. This is generally caused by a relay malfunction. Fixing the relay should solve the problem for the most part. However, if it doesn’t you might want to show it to a mechanic.

The latter is when you hear the whirring sound, but the engine still doesn’t start. However, as you will soon see, such a condition can also be seen when there are other problems. Assuming the problem is with the starter motor, this situation is usually rare. It can occur if you accidentally try to “start” the car when the engine is already at a high speed. Repeating this mistake multiple times leads to the wear of the motor. Sadly, it will require you to change the part completely.

Fuel Pump

car fuel levels
Fuel Problems | Image Credits: Pixabay

As mentioned above, it may be sometimes that your BMW 335i is not starting despite hearing the starter motor, but the motor is not at fault. In such cases, it is usually the case of the fuel pump not sending the required amount of fuel to the engine. The simplest reason for this is that your tank is running a bit low on fuel. If you are certain there’s fuel, then it is mostly the problem of the pump itself a professional will be able to help you troubleshoot it further.

Similarly, there might be a problem with the fuel injectors as well. However, this is quite rare and if it is the case, it can be rather complex. Thus, it is our recommendation to ask your nearest dealership to take a look at it.

Ignition system

Sparkplug Electrodes | Image Credits: Youtube – ChrisFix

The ignition system is one of the first places to look if your BMW 335i is not starting. There are primarily two components of concern at such times – the ignition coils and sparkplugs. The deformation of sparkplugs is one of the most common causes for the engine not starting despite a working fuel pump, battery and starter motor.

This is because the spark plug cannot generate the spark required to ignite the air-fuel mixture due to a deformed electrode. Such a case might occur in one or multiple cylinders. Thus, you can solve this fairly easily by checking every sparkplug. If there seems to be an increase in the gap between the electrodes, replace it. In case you’re not sure about the affected one, change all the sparkplugs.

The ignition coils are responsible for generating the potential that generates the spark in the sparkplugs. While an issue with this part is comparatively rarer than that of sparkplugs, it isn’t impossible. Alas, it is much harder to check the damage if it is done to the ignition coils as it is not apparent. Thus, if the above solution doesn’t work, you can consider changing the ignition coils too. Since it is hard to tell the damaged one apart, you might want to change all of these too.

Final Thoughts

There can be several possible reasons why a car won’t start. The ones listed above are just the most common reasons that you might face with a 335i. Other problems include accidentally triggering the vehicle immobilization module from the anti-theft alarm or facing problems with some of the engine sensors.

To help you narrow down the possible cause, it is best to get an OBD scanner. This will help you read the error codes that the car generates pinpointing which system(s) has the problem. It is a great tool for anyone into DIY. However, while you are working on these solutions, it is important to note that you are working with high currents. Thus, remember to take proper safety precautions and disconnect the battery completely before starting any work.

Otherwise, you could just try the solutions listed here first. If they do not work out, you should try asking a professional from the nearest dealership to help you out. Hopefully, they get your car back working in no time!


Abheek is an Engineering student with a background in Automotive Engineering and Sustainable Energy Engineering. He has worked in Engine Development for a couple of years but is quite interested in Electric Vehicles too! In his free time, he likes to use his knowledge to help others with their car problems. Other times, he can be found following the sport of Formula 1.

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