Do You Really Need Fuel Injection Service, Or Is It Just An Upsell?

It's a pitch you have heard at some point, most likely at a routine oil change at a dealership — that your car would benefit from getting the fuel injection serviced. It can be a pretty pricey add-on too. One Consumer Reports reader wrote that a dealer quoted $185 for a so-called "Super Fuel Service." Consumer Reports did respond that it was unnecessary.

Now there are instances where it'd actually make sense, but in most cases, the gas itself handles the cleaning. Should you choose to get it done, the job mostly involves pushing a cleaning solution through the parts that deliver fuel to the engine. Tune Up Plus, a repair chain from Virginia, describes the process as flushing the injectors and the fuel rail that feeds them. Technicians also clean the throttle body, the part that holds the valve that lets air into the engine. Some chains also put a number on when you need the service. Dobbs Tire & Auto Centers, for one, pegs that figure at around 25,000 miles.

Sadly for these chains, automakers do not share the same enthusiasm. General Motors, for instance, said in a bulletin for its technicians that it simply sees no need to clean injectors as preventive maintenance. In other words, the company only feels an engine needs its injectors cleaned if a problem shows up. Consumer Reports told the above reader that if a car is running fine, it doesn't need any of those extras.

What all this means is that on a healthy engine, a fuel injection service is mostly an upsell. The main reason for this is gasoline itself, which in the U.S. comes bundled with detergent additives. You can thank federal rules from the EPA that went into effect in January 1995 for it. The rules are specifically designed to stop deposits from building up on fuel injectors, among other engine parts. Some gasoline brands can be better at this, though, given how much detergent goes in does vary from brand to brand.

Brands that add extra detergent earn a Top Tier label, a standard that's backed by automakers. Earning this label requires adding more detergent than the federal minimum. The American Automobile Association actually had an independent lab test Top Tier and other gas, and found that engines running the former built up 19 times fewer deposits. Better yet, it found that switching to Top Tier fuel can clear away some existing deposits, too.

Besides Top Tier, another cheap option is a bottle of cleaner you pour into the tank. GM itself recommends adding a bottle of ACDelco fuel system cleaner at every oil change, and nothing more. ACDelco is one of many over-the-counter fuel injector cleaners that typically sell for $5 to $15. By comparison, a shop's version of the service, throttle body cleaning included, costs roughly $150 to $300, according to estimates.

That said, fuel injection cleanups aren't a total scam. Sometimes, when the engine acts up for a specific reason, the service may just be the solution. According to Cars.com, these problems can include stalling and misfires. If you experience these, it could be a sign that your injector is clogged — and might need professional cleaning.

Car companies themselves are a lot more cautious with the approach, though. For instance, GM only approves a cleaning once they're sure the injectors are actually to blame — using its own diagnostic procedures. American Honda goes further, saying that if an injector malfunctions on its Acura models, it should be replaced rather than cleaned.

Worth noting that some types of engines are more likely to clog their fuel injectors. There are four types of fuel injection systems — direct injection, port fuel injection, throttle body injection, and dual injection engines. Out of these, direct injection engines, often called GDI, are more likely to. This kind specifically sprays fuel straight into the combustion chamber rather than an intake port. The Top Tier group says some GDI engines end up with heavier carbon deposits on their injectors. That makes the symptoms above worth taking seriously on a GDI car.