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Fuel injector cleaners, modern day snake oil or does it really charm more mileage from your engine?

Dinesh · Sep 25, 2023 12:41 PM

Fuel injector cleaners, modern day snake oil or does it really charm more mileage from your engine? 01

You’ll find the shelves at your local autoparts store or the automotive section of the hardware shop. Some swear by them while others detest their very existence. The question is, are fuel injector cleaners (FIC) the modern equivalent of snake oil or can this chemical concoction actually charm better performance out of your engine?

Before moving forward, it’s best we get this out of the way. There’s no scientifically quantifiable method to determine if FICs work. The only way to determine that would be to have a control sample car and ensure everything from the fuel to the injectors are identical and cleaned before the variable that’s the FIC is mixed in. You’d also have to run the exact same route on every tank in the name of scientific accuracy.

Fuel injector cleaners, modern day snake oil or does it really charm more mileage from your engine? 02

There's no shortage of them in stores but that doesn't necessarily mean they all work.

Simply put, that’s way to laborious and time consuming for something as menial as FIC. Therefore, the only practical way to know if it works is the good old-fashioned butt dyno and how the engine runs after a treatment.

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Some might argue that there’s really no harm in using a FIC. After all, it’s not like it can make things worse, right? If it doesn’t do anything, your car runs the same and if it does clean the injectors, that means the engine fires more efficiently and burns cleaner, increasing efficiency and fuel economy.

Fuel injector cleaners, modern day snake oil or does it really charm more mileage from your engine? 01

Photo credit: Fuel Injector Cleaner HQ

Nonetheless, some report engines running rougher after introducing a FIC into the fuel. As a consolation, most do agree with the reason behind this. It’s the FIC being too good at cleaning the fuel system, dislodging years and years of particle build up and carbon deposits that end up running through the system and clogging up somewhere.

Furthermore, some manufacturers also caution against using a FIC. Modern engines have more sensitive equipment and harsh chemical such as that in the FIC could cause harm to the internal components, O2 sensors and catalytic converters.

Fuel injector cleaners, modern day snake oil or does it really charm more mileage from your engine? 02

Carbon deposits on the nozzle would lead to compromised spray patterns and imperfect combustion.

Well, the logic goes something like this. Over the years, carbon and other deposits will form in the fuel system on the injectors, valves and in the combustion chamber itself. Given the extremely tight tolerances modern injectors are manufactured to, these deposits interfere with the spray pattern that in turn forms an imperfect mix that reduces fuel economy and diminishes performance.

Much newer engines that use direct injection or high-pressure common-rail (HPCR) diesel engines will see the issue be more pronounced.

You’re not wrong if you notice that over time, your engine seems a little more lethargic and fuel economy seems to be worsening. Wear and tear will do that too.

Fuel injector cleaners, modern day snake oil or does it really charm more mileage from your engine? 03

Carbon deposits usually build up on the valves but cleaning that requires more extensive work. Photo credit: ATS Carbon

Then someone recommends a FIC. You get one from a reputable brand and proceed to follow the instructions, which usually requires emptying the contents into a full tank of petrol and just driving.

But then… nothing happens. You think it might require a few more days or kilometres but again… nada. You run the entire tank and there’s still no difference.

“Do these things even work?” you find yourself pondering.

Fuel injector cleaners, modern day snake oil or does it really charm more mileage from your engine? 04

The difference between an injector that's been cleaned (right) and one with years of carbon build up (left). Photo credit: Auto Parts Express

It might have but again, the differences probably negligible. The fact of the matter is you’re probably not going to feel a significant difference because it’s not a miracle worker. The sluggishness and worsening fuel economy you felt happened over months if not years and therefore, you can’t expect it revert in just a tank of fuel’s distance.

If you continue to use the FIC with every tank of fuel, you might feel a slight uptick in fuel economy or even performance but bear in mind, that could take weeks if not months… if it even happens.

Fuel injector cleaners, modern day snake oil or does it really charm more mileage from your engine? 05

More comprehensive injector cleaning solutions are available (left) but require removing the injectors (right), which isn't something the average owner will do. Photo credit: Car From Japan and Go Mechanic

Then, you can continue to use the FIC to keep the injectors cleaner or reduce carbon deposits building up around the nozzle or other areas of the fuel system.

If you ask us, we’ll recommend using it on a newer car that’s not quite experienced any degradation in performance. Think of it more as preventive care as it could delay carbon deposits in the fuel system.

Fuel injector cleaners, modern day snake oil or does it really charm more mileage from your engine? 06

In the end, everyone prefers the easiest method but it's difficult to tell if it actually does the job. Photo credit: VP Racing Fuels

Just make sure to check your owner’s manual before mixing in the FIC. If it states that mixing in additives into the fuel system will void your warranty, you might want to hold back on that.

On the other hand, if you own an older vehicle, it might not be such a good idea as we’ve mentioned earlier in the article. Older engines would have much more deposits caked-on around the fuel system and the FIC might loosen all this and suddenly, there’s a tonne of debris floating around the fuel system that could lead to worse problems.

In the end, it’s entirely up to you if you should try one with your car.

Fuel injector cleaners, modern day snake oil or does it really charm more mileage from your engine? 07

Dinesh

Writer

“Better late than never.” Some despise it, others begrudgingly agree with it but he swears by it… much to the chagrin of everyone around him. That unfortunately stems from all of his project cars not running most of the time, which in turn is testament to his questionable decision-making skills in life. A culmination of many wrongs fortunately making a right; much like his project cars on the rare occasions they run, he’s still trying to figure out if another project car is the way to go.

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