What is a fuel injector?

A fuel injector is a device for atomizing and injecting fuel into an internal combustion engine. It's consistently under pressure.

Symptoms you require fuel injector replacement

• Check Engine Light is illuminated;
• The engine runs rough or there’s a dead miss in a cylinder;
• There’s a raw fuel smell from the engine or the exhaust.

How to Replace Fuel Injectors?

Tips to remember

It is advisable that when you plan to change the fuel injectors, change them all. Do not change just the ones that are malfunctioning. Pairing brand new injectors with old ones could cause inconsistent performance and a less than satisfactory driving experience. 

WHAT YOU'LL NEED

• Replacement fuel injectors
• Fuel injector seals
• Ratchet & socket set
• Flathead screwdriver
• Pliers
• Towels

STEP:

1. The metal rod over the fuel injectors is the fuel rail. Use the socket and ratchet to remove the bolts and brackets holding the fuel rail in place. Depending on the model, some engines will need the fuel line disconnected from the fuel rail in order to move the rail.

PRO TIP: This step usually depressurizes the fuel system in multi-port fuel injected vehicles, but your engine may vary. Check your repair manual to be sure.

2. Make sure the engine is cold enough to touch. Disconnect the battery.

3. Remove plastic engine covers using appropriate socket. Set covers aside.

4. Use pliers to disconnect the electrical connector on each injector.

5. Lift the fuel rail off of the intake manifold, bringing the injectors with it. This takes a good amount of force, as the injectors are attached to the rail, and the sprayer tips are a snug fit in the intake manifold. Don't use so much force, though, that you deform or bend the fuel rail. Pulling straight up (as the injector is oriented) makes for easier removal.

6. Examine the injector. If you see a small metal clip that looks like a staple, use a small flathead screwdriver to remove or depress the clip. Grasp the injector and work back and forth while pulling to remove from the fuel rail. The injector and rail will drip, so have shop towels ready.

PRO TIP: Before installing the new fuel injectors, dip the fuel injector tip (sprayer end) into a small amount of engine oil. This will wet the seals, preventing leaks. 

7. Press the injector into the rail until it stops. Attach the metal clip, if equipped.

8. Reattach the fuel rail. Line up all the injectors over their respective holes, then press each injector until they slide into place.

9. Bolt down fuel rail. Reattach fuel line. Plug in fuel injector electrical connections.

10. Reconnect battery.

11. Turn the key to the on position and wait 10 seconds before turning to engine start. This will allow the fuel pump to refill the lines and fuel rails before the engine cranks.

12. After the engine drops to the normal idle RPM, turn the engine off. Take a flashlight and check all the injectors for fuel leaks.

How important is replacing your fuel Injectors?

A leaking or plugged fuel injector causes the related cylinder to run rich or lean, both of which can cause long-term problems that require extensive repairs.

In addition, your car’s performance will suffer and your Check Engine light will remain on until the repair is performed.

Is there a break-in period with my new fuel injectors?

Yes & No. All of our fuel injectors are ready to operate upon installation.

Starting the engine and letting it idle for a minimum of 20 minutes is the best thing to do after installing new injectors. This will push the aerated fuel out of the injector nozzle. Failure to do this may create a low/no-fuel condition, which could cause internal damage to the injectors. The new fuel injectors will perform great initially, and you will continue to see increased performance up to 1000-3000 miles as the injectors continue to break-in.

Can you upgrade fuel injectors?

Yes, a fuel injector upgrade is a great option to help add miles-per-gallon or restore lost power and torque in older or high-mileage engines. The first thing to know is "upgrading" does not mean changing the injector flow-rate. Upgrading means replacing old, worn, OEM fuel injectors with a new set of fuel injectors. This upgrade can improve the overall performance of an older engine.

There are 2 types of fuel injectors:

1. Diesel Fuel Injectors

Modern diesel fuel injectors are used to atomize and inject or spray diesel (which is heavier fuel than gasoline) directly into the combustion chamber of the diesel engine for compression ignition (no spark plugs).

Diesel fuel injectors require much higher injection pressure (up to 30,000 psi) than gasoline injectors as diesel is heavier than gasoline, and it takes much higher pressure to atomize the fuel.

2. Gasoline Fuel Injectors

Gasoline fuel injectors are used to inject or spray gasoline directly (GDI) or through intake manifold (multi-port) or throttle body into the combustion chamber for combustion which is ignited by spark.

The design of gasoline injectors varies by type… the newer GDI injectors use a multi holed nozzle, the multi-port and throttle body use a pointless style nozzle. Gasoline injection pressures are much lower than Diesel…3000 psi for GDI and 35 psi for Pinter style.

Clogged Fuel Injectors

It is not easy to diagnose a fuel injector as the symptoms it causes can be like a bad spark plug or ignition coil, meaning, one of the cylinders is not firing. If it is related to a clogged fuel injector it is due to old fuel being run through the engine, resulting in residue getting stuck inside the injector or its filter basket. If a fuel injector becomes fully clogged it will have to be removed from the vehicle and be professionally cleaned, as additives and fuel tank introduced injection cleaners will not be able to clear the clog, as they cannot pass through at all.

Leaking Fuel Injectors

This can be an extremely dangerous situation. If the fuel injectors are leaking externally, you should not drive your vehicle. While a leaking injector will cause issues like that of a dirty one, you will often be able to smell gas or diesel under the hood or even spot a leak, depending on your make and model. Externally leaking injectors pose a fire risk and need to be completely replaced.