Blog Car Care Advice Leaking Fuel Injector: 10 Worrying Symptoms + How to Fix It
Car Care Advice

Leaking Fuel Injector: 10 Worrying Symptoms + How to Fix It

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Getting a whiff of gasoline from your engine?

It could be a fuel leak from a bad injector. Fuel injectors can leak due to a damaged seal or body, leading to issues like rough idling, engine misfires, and oil thinning.

But don’t worry!
We’ll explore how to confirm a leaking fuel injector, what’s causing the injector leak, and what you can do about it. 

Let’s go.

This Article Contains:

9 Telltale Symptoms of a Leaking Fuel Injector

A fuel injector leak could cause your engine to run rich or allow gasoline to reach areas outside the combustion chamber, leading to:

  1. Engine misfire, rough idle, and hard starting
  2. Lit check engine light
  3. Poor engine performance and sluggish acceleration
  4. Gasoline odors from the engine
  5. Spark plug fouled by fuel
  6. Increased emissions and black smoke from the exhaust (due to carbon deposits)
  7. Engine stalling due to hydrolocking, where excess fuel enters the combustion chamber and can’t be compressed
  8. Engine damage due to oil thinning, where fuel mixes with engine oil — reducing its capacity to prevent engine wear
  9. Increased fuel consumption

Now that you know the signs, let’s explore the causes.

What Causes Fuel Injector Leaks?

Your leaky injector could be due to:

But what can you do about it?
Let’s find out. 

What Can I Do about a Leaking Fuel Injector?

Resolving leaking fuel injectors can depend on the problem.

It can be repaired if:

  1. The leak is at the top of the O-ring near the fuel injector rail. You’ll need to replace the O-ring.
  2. The leak is due to a clogged injector. You’ll need to clean the bad injector.

However, a damaged fuel injector body or corroded parts can’t be mended. You’ll need to replace the leaky injector.

Next, we’ll explore some fixes.

How to Inspect and Clean a Bad Fuel Injector

Dealing with leaking fuel injectors requires some knowledge of fuel system parts. If you’re unfamiliar with it, it’s best to seek professional help.

Here’s how a mechanic would confirm the leak:

  1. Turn the car on and let it idle. 
  2. Look for a lit check engine light.
  3. Raise the car’s hood and inspect the fuel injector rail for a fuel leak. They’ll look for visual signs of fuel stains, wetness, or pooling of fuel.
  4. Check for a gasoline smell around the engine bay or fuel injector area.
  5. Conduct a fuel pressure test and dye test to confirm the fuel leak.

Depending on the problem, they may use one of these processes:

A. Manual Cleaning for Clogging and Damaged O-rings

  1. Remove the fuel pump fuse. They’ll wrap the leaking injector in a towel to absorb the gasoline. 
  2. Start the car and allow it to run until the engine stalls to relieve the fuel pressure within the rail.
  3. Disconnect the injector wiring harness and remove the fuel rail bolts. They’ll remove any associated fuel lines or clamps that prevent them from lifting the rail.
  4. Lift the fuel rail, pull out the O-rings, and remove the injectors.
  5. Replace any damaged O-rings.
  6. Let the injectors soak in a bucket of carburetor cleaner for several hours to remove carbon deposits.
  7. Rinse the injectors with clean water and blow them dry with compressed gas.
  8. Fit the injectors back into the ports within the engine, reinstall the O-rings, and reattach the clamps and fuel line.
  9. Bolt the rail back into place.
  10. Reinstall the fuel pump fuse and start the car to confirm the injectors aren’t leaking.

B. Using Fuel Additives to Clean Dirty Fuel Injectors

  1. Pour the specified amount of injector cleaner into the fuel tank. Fill the tank with fuel if it’s added to a near-empty tank.
  2. Start the engine and let the solvent clean the injector.

Note: A mechanic may do this after every oil change to prevent a clogged injector.

Now, let’s see how much it’ll cost to replace a leaking injector.

How Much Does it Cost to Replace a Leaking Fuel Injector?

A fuel injector replacement could cost between $300 to $900, including parts and labor charges. However, the cost can vary depending on your vehicle model, the fuel injector’s brand, and your mechanic’s location.

Read on to explore some common doubts surrounding the fuel injection system. 

4 FAQs about Fuel Injectors

Here are answers to questions you may have about fuel injectors:

1. How Do Fuel Injectors Work?

The fuel injection system delivers atomized fuel into the combustion chamber.

In a mechanically controlled fuel injector, the fuel is transported under pressure to the injector through a fuel line. The pressure pushes the valve spring that moves the plunger forward, opening the nozzle and spraying the fuel. Once the pressure drops, the spring returns to its original position and the nozzle closes, stopping the spray.

In an electronically controlled fuel injector, the Engine Control Unit (ECU) directs the fuel pump to send fuel to the injector. The ECU then signals the electromagnets in the injector to push the plunger forward, which opens the nozzle and sprays the fuel.

Once the injection cycle is completed, the ECU deactivates the electromagnets. This causes the plunger to return to its initial position, closing the nozzle.

2. Can I Drive with a Leaking Fuel Injector?

No, you shouldn’t drive with a fuel injector leak.

An injector leak can cause your engine to run rich, which can lead to hard starting, misfires, and severe engine damage. Your car could also catch fire if excess gasoline collects in the engine.

It’s best to call a mechanic immediately if you suspect a fuel injector leak.

3. What’s the Difference Between a Leaking and Clogged Fuel Injector?

Clogging is a common fuel injector problem that occurs due to the formation of carbon deposits during combustion.

If you have a clogged injector, you’ll have less fuel flowing into the engine and may notice signs like:

In contrast, an injector leak will have excess fuel flowing into the engine, triggering symptoms like a gasoline odor, engine oil thinning, or hydrolocking. 

Note: A car with over 60,000 miles will likely have fuel injectors with carbon deposits. 

4. When Should I Clean Fuel Injectors?

Typically, fuel injectors should be cleaned every 36 months or 45,000 to 100,000 miles. Cleaning your dirty fuel injectors helps prevent clogging and leaking. 

That being said, it’s best to leave fuel system service to professionals who can replace cracked or damaged parts.

Resolve Your Fuel Injector Leak with AutoNation Mobile Service

A fuel injector leak can cause increased fuel consumption, car performance issues, and severe engine damage. Resolving the leak promptly can help you avoid accidents or costly repairs.

Need a mechanic to come to you?
AutoNation Mobile Service can fix your fuel injector problem straight from your driveway, whether it’s a clog or a fuel leak. 

Contact us to resolve any fuel injector or other auto issue and get a 12-month, 12,000-mile repair warranty.