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This article gives detailed instructions on cleaning fuel injectors using a nozzle jet tool in a BMW engine with "port" style fuel injectors. Even though we used a 1995 840i to perform this repair, this article can be applied to any BMW or MINI vehicle with port style (non-turbo) fuel injectors with minor modifications to the repair steps.
A BMW fuel injection cleaner kit can be purchased for under $20 and does the same job as a professional service.
If you own an older BMW or MINI and perform your own maintenance and repairs, there will come a time when you will need to learn how to clean fuel injectors at home. No matter how conscientious you are with your octane choices and fuel additives, you will get clogged fuel injectors at some point. Just about every gallon of gasoline we pump into the tanks of our vehicles is contaminated with water, dirt, and/or rust - it is just a matter of time before these impurities move beyond the fuel filter and into the engine.
So what is the "best" fuel injector cleaner for the home mechanic?
As is with all articles that recommend certain tools, it comes down to semantics; how do we define "best" as it relates to the do-it-yourself mechanic working out of their garage. We think the best BMW fuel injector cleaning kit for the home mechanic means three things; it properly cleans the injectors, it is easy to use and it is inexpensive.
Fuel injector cleaner tools
All you have to do is run a quick online search on fuel injector cleaning, and you will quickly realize there are an overwhelming amount of products and services on the market. Fuel injector cleaning kits can run anywhere from $100 for a simple pressurized "no injector removal" tool to over $1000 for a professional ultrasonic cleaner and tester. Further exacerbating the issue are the countless opinions and reviews scattered across automotive forums making the choice even more complicated. Many BMW and MINI home mechanics become frustrated and just resort to installing new fuel injectors to avoid cleaning them altogether.
The bottom line is this. If you can remove the fuel injectors from your BMW (which for most models is fairly simple), you can clean them just as well as any professional service for under $20. Yep, you read that correctly...$20. There is absolutely no need to purchase an expensive professional fuel injector cleaning tool if you are a home mechanic servicing your own car. Those tools are great for repair shops that clean hundreds of injectors a year, but for the do-it-yourself-er doing just one vehicle they do not make economical sense.
At the BMW Repair Guide, we use a simple nozzle jet fuel injector cleaner tool to service the port-style fuel injectors in all of our older non-turbo vehicles, including our MINI Cooper. Note that we said port-style fuel injectors and not a direct injection; there is, unfortunately, one limitation to the nozzle jet fuel injector tool - it won't work on BMW turbocharged engines with direct injection. For more information on this, see the "advantages versus disadvantages" discussion at the end of this article.
The nozzle jet fuel injector tool
The nozzle jet fuel injector cleaning kit is a very simple apparatus that almost seems too good to be true. Since you can pick one up cheaply on Amazon for about $14, we must admit we were a bit skeptical that it would even work. It operates under the same principles that run the fuel injectors in your car; a 12V power source is used to energize the injector's solenoid forcing its valve to open while a cleaning agent is sprayed under high pressure flushing out any gunk and debris.
We first tested the nozzle jet fuel injector cleaning kit on some very nasty injectors in our 1995 840ci V8 engine. These were the original 25-year-old fuel injectors and they did not look as if they had ever been removed from the intake manifold. After the first couple shots of the cleaning agent through the injectors (we use CRC Clean-R-Carb), the spray quickly changed from a malformed drizzle to a nice uniform pattern. We jetted each injector six times with CRC Clean-R-Carb, reassembled the fuel rail and tested the engine. The results were remarkable; the engine idled smoothly and performed like it had new injectors installed. We were able to clean and reuse $500 worth of fuel injectors using a $14 tool.
In a nutshell, the nozzle jet fuel injector cleaning tool worked great. It is very simple to use and contrary to popular belief, there was absolutely no mess. In fact, if you are getting a cleaning agent all over your hands when using this kit, then you are using the tool incorrectly. Please see our video above or our step-by-step instructions below on how to properly use the tool.
We have since used the nozzle jet fuel injector cleaning tool on all of our non-turbo vehicles here at the Repair Guide including our E36 M3, E46 325i, E60 530i, E64 645ci, and R56 MINI Cooper. It is a great tool - there is nothing fancy about it but it gets the job done, is easy to use, and is inexpensive.
Advantages versus Disadvantages of the Nozzle Jet Fuel Injector Cleaning Kit
- Low cost. Can be purchased on Amazon for less than $20.
- Very easy to use.
- Uses an inexpensive aerosol cleaning agent (we us CRC Clean-R-Carb) that can be purchased on Amazon or any local auto parts store.
- Simply uses the power from your car battery. No compressed air or fancy equipment needed.
- One person operation (no assistance required).
- The fuel injectors must be removed from the vehicle to be cleaned.
- It does not work on BMW direct injection engines like the N54, N55, or any of the diesel or newer twin-scroll turbocharged engines (it does work on the MINI S turbocharged engine which has port injection). Direct fuel injectors unfortunately have a different plug configuration and will not work with the tool. These style injectors will need to be professionally serviced or replaced if they are malfunctioning. If you are not sure what type of fuel injector you have, the simple rule of thumb is if you own a BMW turbocharged or diesel engine, then this tool will not work.
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Section 1 - Using the Nozzle Jet Fuel Injector Cleaner ToolAs discussed above, the nozzle jet tool requires that the fuel injectors be removed from the engine of your BMW or MINI. This is actually a simple process on most naturally aspirated (non-turbo) engines and should not be intimidating at all. Please also see our video at the beginning of this article for using the tool.
- Lay the fuel injector cleaning kit out on a bench and identify its parts. It should have two power cables with different size plugs and two plastic nozzles with two different size openings.
- Choose the plug that matches your size fuel injector and firmly insert it.
- Choose a plastic nozzle with an opening that fits your fuel injector. Install the fuel injector into the nozzle making sure the o-ring is firmly seated in the opening.
- Connect the tool to the negative terminal of a 12V power supply. Your vehicle's battery is the best choice.
- Remove the spray nozzle from a can of aerosol fuel injector cleaner. We use CRC Clean-R-Carb.
- Insert the can of fuel injector cleaner into the tool's plastic nozzle.
- With one hand, push the plastic nozzle firmly down on the can of aerosol cleaner.
- With the plastic nozzle firmly pushed down on the can of cleaner, use your other hand to touch the positive terminal with with the tool.
- Touch the positive terminal for one second intervals, five to six times. It is suggested that you do not energize the fuel injector for longer than one second intervals to avoid internal damage to the solenoid. You should see the spray pattern start to change after a few tries as the fuel injector is internally cleaned. Repeat on the rest of the fuel injectors and reassemble the engine.
BMW Fuel Injector Cleaning Kit Instructions Finished