How to Install a GM Duramax Fuel Injector

If you plan on installing a GM Duramax fuel injector into your vehicle's engine, you'll need plenty of tools to get the job done right. Gather 10 mm and 13mm sockets, a ratchet, a flat blade screwdriver, a Phillips screwdriver, pliers, a drip pan, a funnel with a screen or filter, a vacuum, a pry bar and white grease.

Begin by removing the spark plug wires at the front of your engine. There's a 2, 4 and a 6. The one in the front closest to passenger side is 2, the one in the middle is 4 and the last is 6. Put tape around them for markings that will allow you to put them back in place correctly. To remove them, pull and twist at same time, pull the clip off and they'll come back free. Remove the hoses from the top. On the clip, you'll see a 10mm bolt. Remove it. Loosen up the bolts on the air intake hose's clamp with a flat blade screwdriver. Then pull the hose off, back and away. Disconnect the hose that is connected to its top and the harness on the side. Pull it free and away. You'll see two 13 mm bolts at top corner and also diagonally and across. Remove those. Then remove the bolts that secure the coil pack. The top two bolts are 10 mm, the bottom two on the back are 13 mm.

Use a pair of pliers to grip the clip and slide it back on the hose. Use a flat blade screwdriver to pry the hose off. You'll see two 7mm bolts that must be removed. Once removed, disconnect the harness on the bottom, pull it up and out. Use flat blade screwdriver to pry that hose off. You'll see two 10mm bolts on either side of the EGR. Remove them. Remove the upper intake plenum. The 10 mm socket removes the 10mm bolts and the 13 mm nut. Remove them all. Also, remove the cap on the radiator overflow bottle. Take a drip pan and slide it underneath the engine, below its hoses. Take the pliers and push clamps and slide them back on the hose. Take the flat blade screwdriver and pry the hose back and off.

When the hose is disconnected, the coolant will come out onto the drip pan. Leave the screwdriver in there to drain all the coolant. You can also drain the coolant quicker by loosening the coolant's bolt. Once it has drained, the hoses should stayed pried off and they should be pulled free. Remove the gaskets as your new kit likely comes with new ones. You'll see two 10 mm bolts. Remove them. Vacuum out the top of the engine. Get rid of dirt and gunk. Use the pry bar to carefully pry the fuel injector up and out. When pried up enough, you can lift it out by hand.

Pull on the little metal clip above the fuel injector. Move the fuel injector back and forth and pull it free. The o-ring will stay up inside there. Use your small flat blade screwdriver to pull o-ring back out and put it back onto the fuel injector. Then push the new fuel injector up in there and replace the clip. Put white grease around the edges of each fuel injector. You can now put your fuel injector leads back into place according to each's appropriate number. Once the leads are in place, line up fuel injectors and push them down into place. Replace the two bolts and connect the lead on the alternator. Take the new gaskets from the gasket pack and put them into place (one for each side).

Replace the nut down by the line that you just plugged back in along with the nut right down below it. Take the bracket in gasket set and line it up with upper intake plenum. Make sure the harness goes up through hole in the back on the right. Put plenum into place. Replace all the bolts that go along it. If there is a bracket, put a bolt down through the bracket.

Replace the coil pack bolts to secure the coil pack back into place. Tighten them up. Put the hose back into place. Take the clamp and use the pliers to slide it forward and lock it back into place. Replace two bolts back down underneath the coil pack. Reach down with a flashlight to see where holes are and put them in position by hand first and then tighten them up. Bolt the throttle body back into place. Replace the nut on the bottom corner of the throttle body. Replace the bolts up above the throttle body and tighten them. Push the hose back and slide it down into place and push the clamp forward. Before putting the EGR on, put the new gasket into place and replace the bolt on both sides.

Put the air intake hose back in. Pull the intake cover back and put the hose into place. Slide the cover forward until you can snap it down into place. Tighten the Phillips screws and then the bolt clamps with a flat head screwdriver. Put the connector back into place and put the hoses back into the clip. Take the EGR connector, plug it back in and also plug in the spark plug wires. Finally, use a funnel with a screen or filter to pour coolant back into radiator overflow bottle.