How to Clean Your Car’s Fuel Injectors
Keep those high-tech squirt guns performing at their best.
- Auto Repair and Maintenance
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So you want to clean your car’s fuel injectors? Maybe you want to maintain your fuel system's cleanliness from new, or your older car is misfiring, idling roughly, or otherwise running poorly. Maybe you’ve found yourself at the mercy of the dreaded Check Engine Light and your OBD scanner reads P02(xx), car-computer speak for a fuel and air metering issue. Well, you’ve come to the right place. Your injectors may be bunged up, reducing their flow rate or screwing up their fuel-spray pattern. The Drive’s crack How-To department is here to help and get those injectors injecting properly once again.
Your fuel injectors are called upon every day to perform little miracles of precision fuel metering. Makers of fuel-injector treatment products pledge to keep your injectors in peak condition. For this they use detergent agents that mix with the fuel in your tank to break up deposits caused by gasoline impurities. However, if your injectors have become clogged, they will likely need a physical cleaning.
Note: If your injectors are clogged substantially, it may be time to consult a mechanic. Deep cleaning is a process requiring specialized skills and dangerous, controlled solvents. Ultrasonic vibration is often used to break up deposits, followed by high-pressure flushing, media blasting, and the replacement of rubber seals. At this point, it may be worth replacing the injectors altogether.
Here’s how to do it.
Estimated Time Needed: 30 minutes to 1 hour
Skill Level: Beginner to Intermediate
Vehicle System: Fuel system
Working on your car can be messy and dangerous, especially when you’re working with your car’s fuel system, which you’ve likely never bothered to clean—please don’t queue Prodigy’s Firestarter. Here’s what you’ll need to keep your jeans and shirt spotless, and eyes and skin injury-free.
Everything You’ll Need
We’re not psychic, nor are we snooping through your toolbox or garage, so here’s exactly what you’ll need to get the job done.
- Wrench set (socket and regular)
- Air compressor (for cleaning kit)
- Fuel system cleaner
- A fuel-injector cleaner kit and new injector o-ring seals (if needed)
- A complete set of new fuel injectors (if needed)
You’ll also need a flat surface, such as a garage floor, driveway, or street parking, though check your local laws to make sure you’re not violating any codes when using the street. When using cleaning solvents, make sure the work environment is properly ventilated.
Arranging Your Workspace
Organizing your tools and gear so everything is easily reachable will save precious minutes waiting for your handy-dandy child or four-legged helper to bring you the sandpaper or blowtorch. (You won't need a blowtorch for this job. Please don’t have your kid hand you a blowtorch—Ed.)
Here’s How To Clean Your Fuel Injectors
Let’s do this!
Cleaning Your Injectors (Beginner)
Over-the-counter fuel-injector cleaners contain detergents purported to break up carbon deposits. These products are best used before any serious injector issues arise.
- Into a nearly empty fuel tank, or as directed, pour the entire contents (or specified amount) of fuel-system treatment.
- Fill tank with fuel (16-18 gallons or as directed).
- Repeat at every oil-change period.
- You’re done. Congrats.
Cleaning Your Injectors (Intermediate)
- Consult instructions for your fuel injector cleaning kit.
- Remove the cap from the fuel injector canister.
- Fill canister with recommended cleaning solution.
- Hang the canister under the hood in a convenient location above the engine.
- Locate the fuel rail test port (consult your repair manual if unsure).
- Using the proper adapter, attached the canister hose to the fuel rail test port.
- Locate the fuel pump relay in the fuse box (consult your repair manual if unsure).
- Disconnect the fuel pump relay, as directed.
- Attach air supply to the canister's air port.
- Adjust regulated system pressure, displayed on the meter, as directed (usually a few pounds lower than normal fuel-rail operating pressure).
- Start car.
- Wait until all of the solution has flowed through the fuel rail, and the canister is empty (5-10 minutes).
- Release the line pressure and disconnect air supply.
- Disconnect the hose from the fuel rail.
- Start the car.
- You’re done, you garage hero you. Congrats!
Replacing Your Injectors (Intermediate)
- Using Google, or the proper repair manual for your car, find out where the fuel injectors are.
- Allow the engine to cool completely.
- Remove any parts that may hinder access to the injectors.
- Put aside any removed parts, along with related hardware, in order of disassembly.
- Disconnect the wire connector on each injector.
- Find and disconnect the fuel line from the fuel rail.
- Pull the fuel injectors from the fuel rail (watch for leaking fuel).
- Lubricate the new injectors' seals with fresh gasoline.
- Insert the new fuel injectors into the fuel rail.
- Reinstall the fuel rail, making sure to align properly.
- Reattach the fuel line to the fuel rail.
- Connect the wire connectors to injectors (make sure they snap in).
- Turn key to accessory position for 30 seconds to activate the fuel pump.
- Start car.
- You're done. Congrats.
Tips From a Pro
Over the years, The Drive’s editors have done it all and seen it all, buying, selling, and reviewing just about every car on the planet. We’ve also wrenched, ripped apart, and fixed a ton of cars, including some that needed a good fuel system deep clean. Here are our top tips to ensure your car is running right.
- If you’re storing your car for a prolonged period of time, consider using a fuel stabilizing additive to ensure everything remains gunk-free for your next drive.
- More modern cars have highly complicated injection systems, after consulting Google or that manual we spoke of earlier, it may be time to call in the pros.
Since you may not have access to the right tools, or have a friend you can bum a wrench off of, we also compiled a list of our best hacks to make your life easier and drain your pocket less.
- Buying the right fuel will ensure your car’s injectors run cleanly. Simple as that.
- Every few years, drop in the fuel system cleaner and you’ll see a world of difference.
Got a question? Got a pro tip? Send us a note:firstname.lastname@example.org