The fuel injectors on your BMW are integral to the engine’s normal operation. As their name suggests, the fuel injectors are responsible for delivering fuel into the engine cylinders or combustion chamber. They atomize the pressurized fuel from the fuel pump into a fine spray that is then mixed with air and combusted within the cylinders. This happens several times a second and is a crucial step in the functioning of a modern-day internal combustion engine.
As you can imagine, a faulty fuel injector can be a serious issue. If your engine isn’t receiving the appropriate amount of fuel, it will be unable to produce the power required to keep the car running. If you have owned a car long enough, bad fuel injectors are something you cannot escape — they will wear out eventually and require cleaning or a replacement.
What Are the Causes of Bad Fuel Injectors?
There are several reasons you may be dealing with bad fuel injectors. As mentioned, they constantly work when the engine is running and will fail eventually. However, in some cases, they can fail prematurely. If this happens to you, check out our selection of genuine BMW and OEM fuel injectors. We offer the sharpest prices online!
Poor Fuel Quality
One of the most likely causes of fuel injector failure is substandard fuel quality. Low-quality fuel can contain several impurities that can accumulate around the fuel injector’s nozzle, affecting how effectively it sprays fuel. The fuel filter in your car is designed to keep these impurities out, but with terrible fuel, some debris may get past it.
If you often fill your Bimmers tank with poor-quality fuel, you might have to deal with bad fuel injectors sooner than expected.
Wear and Tear
The next most common cause of faulty fuel injectors is regular wear and tear. There are multiple moving components inside a fuel injector that are actuated by a solenoid. Over time, these parts will wear out, and the injector is bound to fail.
A fuel injector will also get clogged with carbon build-up since it’s exposed to repetitive combustion cycles. If your engine isn’t burning fuel efficiently, it can cause carbon sediments from the cylinders to deposit around the fuel injector nozzle and clog it.
Incorrect Installation
Lastly, you will also face issues if one of the injectors is disconnected. A fuel injector that isn’t installed right can spray incorrect fuel values, resulting in either a rich or lean mixture, inevitably affecting the engine and its performance.
What Are the Symptoms of Bad Fuel Injectors?
Since the fuel injectors are integral to the regular operation of your engine, any issues with them will result in rather apparent symptoms. While some may be more severe, it’s best to address any signs of bad fuel injectors as soon as you notice them.
Engine Misfiring and Unsteady Idling
When the fuel injector cannot deliver the appropriate amount of fuel into the engine cylinders, it can cause the engine to misfiring and idle erratically. The ECU is programmed to constantly alter how much fuel is delivered into the combustion chamber based on factors like throttle input and ambient conditions. A clogged injector cannot accurately deliver this required amount of fuel, resulting in engine misfiring or knocking and shaky idling.
Reduced Fuel Economy
If your fuel injectors are bad and enough fuel isn’t being injected into the engine, the ECU will try and supply more fuel to the engine to compensate. However, since this fuel isn’t being correctly atomized and sprayed into the cylinders, it will continue to burn inefficiently, reducing fuel economy.
Reduced Performance
With a clogged or dirty fuel injector, the cylinders won’t receive the increased fuel required for higher performance. In some cases, you might find that your engine usually behaves when it’s at idle but stutters when you press down on the accelerator. While you will face similar symptoms as seen with a faulty fuel pump, it might also be due to the injectors.
Smoke from Exhaust
When fuel isn’t burnt up efficiently inside the engine, it will result in a cloud of thick black smoke from the exhaust. This could happen when the fuel injectors aren’t delivering the right amount of fuel to the combustion chamber. In any case, excess emissions from the tailpipe are a sign your car needs to be diagnosed for any issues.
Check Engine Light
An illuminated ‘check engine light’ on your dashboard is never a good sign as it means that something is wrong with your car. On older Bimmers, you will have to plug a diagnostic device into the OBD-II port on your vehicle to scan for error codes to narrow down on what the check engine light signifies. Ultimately, this is the most accurate way to tell if a symptom you are facing is related to the fuel injectors.
How to Check for Bad Fuel Injectors
There are multiple methods you can employ to check if your fuel injectors are faulty and warrant replacement. In almost any case, the first step will be to use an OBD-II device, as we mentioned above, to confirm if the symptoms you’re facing are related to the fuel injector. Depending on the year and model of your Bimmer, the Diagnostic Trouble Codes (DTC) may vary slightly, and you should be able to get some help with a quick search online. For example, in the case of the BMW N54 engine, some fuel-injector-related error codes you may see include the following:
- 29DC (10716) – Cylinder Injection Switch-off
- 29E2 (10722) – Fuel Injection Rail, Pressure Sensor Signal
- 2FBF (12223) – Fuel Pressure at Injection Release
- 30BE (12478) – Injector, Calibration Plausibility
Once you’ve ascertained that you are dealing with bad injectors, the next step is finding out which one is causing problems.
One way to do this is with the clicking test. Take a metal screwdriver and touch the end against the fuel injectors as the engine is running. Put your ear to the screwdriver’s handle and listen for a clicking sound — if there is one, the injector is working. If it’s silent, it may have to be cleaned or replaced.
While this is the simplest way to test which injector is faulty, it may not always be accurate. You will have to carry out a voltage or leak test for a more concrete picture.
Voltage Test
To carry out a voltage test, you will need a voltmeter or a multimeter. Ensure you’re wearing safety gloves and that the engine is cool when you perform this. First, turn the ignition on but don’t fire up the engine. Then, connect the multimeter to the negative terminal of the battery. Disconnect the fuel injector wiring and check the connector with the voltmeter to see if the reading matches the manufacturer’s specifications. If it is off, it’s time to replace the particular injector.
Leak Test
A leak test is more straightforward and includes a thorough visual inspection around the injectors to check for trace fuel residue. If an injector is not installed correctly, it can leak. You should carry out both tests since a leaking injector may still have an accurate voltage reading.
How to Fix Bad Fuel Injectors
In many cases, fuel injectors can be cleaned. However, the effectiveness will depend on how much carbon build-up has occurred around the injector and whether any of its components have worn out. If it’s mild, you should be able to mitigate excess carbon build-up by running a fuel injector cleaner through the fuel system.
However, if the fuel injectors are severely clogged and cannot be cleaned, the only solution is to replace them. You should know that if one injector has failed, the others will likely follow. For that reason, it’s worth replacing all of them when one fails, so you can avoid the time and labor cost involved with having to do each at a different time.
Get Genuine BMW Parts at Bimmers.com
Replacing multiple fuel injectors on your BMW can be expensive. But the cost of doing so will be much less than what you might have to endure if you leave the issue unaddressed. At Bimmers.com, we ensure you get the best possible prices on genuine OEM and aftermarket parts. When you shop from us, you’re shopping from people who love cars as much as you love yours and are dedicated to delivering the best possible experience.
