Your car relies on the fuel injection system to supply the fuel required to keep the engine running. Each injector is constructed from components including springs, coils, nozzles and more. If any of these pieces fails, it could render the injector useless. When an injector fails, you'll have to replace it. Luckily, you can do the job yourself if you have a bit of mechanical aptitude. Here's a look at what you need to know to get started.
1. Gather Supplies for the Job
Before you get started, make sure that you have everything that you need. You'll want a stash of clean rags just in case the injector leaks fuel. You'll also need to have a basic screwdriver set, wrenches and a ratchet and socket set. Consider investing in a ratchet extension to make it easier to reach the more difficult areas, and talk to your local auto parts shop about an injector puller to make it easier for you to get the fuel injector out.
2. Remove the Injector
Ease the Fuel Pressure
Before you remove the injector, you'll need to relieve the pressure in the fuel line. This helps to reduce the risk of any serious fuel leakage from the injector when you pull it out. Look for the pressure release valve along the fuel rail atop the engine. It will look similar to the air valve on the tire of your bicycle. Wrap the valve in a shop rag, then press the top of the stem through the rag with a screwdriver. If you can't find the valve, there's another option to ease the pressure.
Look for the fuel pump relay in the relay panel under your dashboard or along the firewall. The cover to the relay boxes will tell you what each relay is for. Disconnect the plug to the relay to cut the power to the fuel pump. Then, start the engine and run it until it stalls.
When the fuel in the lines has been exhausted, the car will shut off. This releases the pressure along the fuel lines, because the pump can't engage and push additional fuel along the system. Plug the relay back in so that it will function when you start the car again.
Pull Out the Old Injector
Disconnect the negative battery cable. You'll probably need a wrench for this. Then, move any accessories from the top of the engine so that you can get to the fuel injectors. Make sure that you keep a note of everything you removed and how it connects so that you can be sure to get it back where it belongs afterward. You may need to remove the air cleaner or similar components as part of this process.
Disconnect the wiring harness from the fuel injector that you're removing. Then, push the lock tab on the outside of the injector and pull the connector off the top. Remove the fuel rail by unscrewing the mounting screws.
Lift the fuel rail away and pull the injector out of place. Use an injector puller to make this easier, and have a rag handy in case there's any fuel leakage. Pull any gaskets or seals out of the space as well, as you'll need to replace these when you install the new injector.
3. Install the New Injector
Align the new injector along with any necessary washers or seals, then put it into place. You'll want a ratchet and socket to secure the injector in place. Make sure that the injector sits flush in the manifold. Secure the fuel rail in place and replace the mounting hardware. Connect the wiring harness to the new fuel injector.
Replace any additional accessories that you removed to get to the fuel rail. Follow the notes you took as you disassembled these pieces. Reconnect the negative battery cable. Finally, put the key in the ignition and turn it to the ON position to engage the fuel pump. This will start the fuel pump to restore fuel to the lines. Then, you can start the ignition and test the new injector.
With the information here, you can replace that fuel injector that's been plaguing your car's engine. If you aren't comfortable doing it on your own, you may want to talk with local SR20DET injector specialists about giving you a hand.