GM 4.3L Fuel Injector Replacement

This in-depth video demonstrates a fuel injector replacement on a GM 4.3L application.

Let’s talk about injector replacement on a 4.3 liter GM product. Now, today we’re working on a 2001 Chevy S-10 pickup. This donor vehicle’s got well over 300,000 miles on it already. And we’ve got a couple of stuck poppet valves on various injectors here. And so, we could have replaced these components individually, but because of the high mileage on the vehicle and the fact that we’ve gotten more than one of them bad, let’s go ahead and replace the complete unit here. Today, we’re going to be installing an updated unit. So it’s going to look a bit different, but the design is much better. And so, we’ve already gone ahead and removed the upper intake. Now, before we remove the actual injector unit, we have to pay special attention to the routing of the tubes and the different poppet valves there. So one tip here is, right away, a lot of people today have cell phones with cameras on them, or if you’ve got a smartphone, it’s got a camera. Go ahead and snap a couple pictures. It might certainly aid you when it comes time to re-install the new one.

Well, let’s take a look at our new unit here. I’m going to open it up out of the box. And first thing in the box, we’re going to notice an instruction sheet. Now I’ll be the first to admit, like a lot of guys out there, when do we read instructions? After the job’s gone wrong, but I’m going to strongly encourage you today to take a minute to read the instructions. Talks a little bit about the new updated unit, also gives a correct routing here of how we need to reroute the tubes before we install it. So pay special attention to the instructions that come with the unit here and which way we’re going to route these injector tubes.

So now let’s remove the unit out of the box. And as we take a look at this, you’ll notice it certainly looks much different than the original unit. Whereas originally the injector part of it was mounted up here in the plastic body. And then, we had spring-loaded poppet valves down here where it inserts into the intake. Well, due to some design changes, now the actual injector itself is mounted down here at the bottom. So that’s why we see some wires in here and some different connectors. This is a direct replacement unit for the previous design though. You also notice that we’ve got a fuel pressure regulator installed on the backside here. Now, there’s not going to be a hose going to this, nothing to connect to, because rather than reference to atmospheric pressure, this is going to be referenced to intake manifold vacuum. This is already mounted inside the engine. So there’s no connection to be made right here. Well, let’s take a look at how to remove the old unit. We’re going to show some cleaning tips and then how to properly install the new unit.

All right, well now let’s remove the old injector unit. First, we’re going to take just a small pry bar or screwdriver, and there’s a couple of retainer clips holding the main body in place. So we gently pry against it, pop those clips out.
Once we get the complete unit loose, now we can remove the poppet tubes. We’ll work our way around gently squeezing the retainer tabs. Sometimes you might have to twist it a little bit or wiggle it around a little bit, but they should come out with very little effort. And once everything is released, it’s going to be time to remove the entire unit.

Now that we’ve got the old unit removed, we’re going to do a little bit of cleaning here, which is going to aid in the installation of the new unit. All right, now we’ve got our old injector unit out and it’s time to clean up these passages. You notice there’s a lot of grime in here. There’s a lot of carbon buildup. We’re going to use a little brush such as this one here. You see, this is perfect. This is actually a little two-step brush. It’s got an inner narrower piece and then the broader outside, and that’s going to work perfect for inside our little bore here. Now, if you don’t have this tool, use a pipe cleaner, maybe even a rag over a screwdriver or something like that, just anything to clean out some of these ports here. And we’re going to remove that carbon. We want to have a nice clean surface so we can slide our new injector in. When it’s all done, we might want to take a shop vac and vacuum out any of the debris here and make sure that it’s not going inside the engine.

All right, before we install our new injector unit, once again, you can see that the injector is actually at the end here. So we’re doing a complete one piece unit. As I said before, these are available individually, but we’ve already had two of them bad here, high mileage vehicle, we don’t want to go back in and replace the other four a week later. So we’ve decided to replace the complete unit here. We need to do a little bit of a lubrication on the tips here, as well as the O-ring seal at the top here, where this goes up to the upper intake cover. And so I’m using a little bit of a transmission assembly gel here. It’s an automotive grade lubricant. You might choose to use petroleum jelly. Even clean engine oil is certainly better than installing these things dry. So I’m simply going to put a little bit of this lube on each one. It’s going to help it slide in a little bit better and help it get a good, tight seal once we install this down into the intake manifold. And of course, make sure our O-rings are good and lubed up. Also, the fuel lines, where they come from the tank, are going to come in the top here. And so once I remove these caps, once everything’s installed, I’m going to lubricate these steel lines because we’ve got a couple of O-rings inside here. We don’t want those rolling over, getting pinched off either. So lubrication is the key here to a successful installation. Now we’re ready to install our new unit. Not a bad idea, once again, to have our instruction sheet very handy.

So, to help illustrate the installation process a little better, we’ve got an intake manifold removed and cleaned up here on the bench a little bit. You can see with the original casting that there is numbers of the cylinders already in here. We simply highlighted them a little bit to make them easier to see, but we’ve also put some additional numbers here just for illustration purposes. Same thing with the injector unit. It comes with numbers on here already, but just to make it a little easier to see for the purposes of this video, we’ve installed some other numbers here. Now we’ve installed our new bracket. Now, it’s going to have a little bit of a loose fit because we are going to need to move it around here. That’s the way it is. Don’t worry about that. So it’s going to be kind of a two-part deal here. We’re going to have to kind of put this towards the bracket and then we need to move our tubes and route them properly before we lock anything in place. So we’re going to kind of gently begin our installation process here, put the tubes in. And as I mentioned before, it’s nice to have these lubricated, but for the purpose of this, we’re going to do them dry. Now, once we’ve got everything roughly configured here and our routing properly, we can insert this down in the bracket, lock it in place, and then we can go back to each of our injectors and lock them in place. It’s very important to do this kind of together because once these things are locked in, it’s very difficult to get them back out again.

So, if we take a look at our routing here, again, we can see that everything’s installed properly. We’ve got number one, three, and five here in what would be the driver’s side of the engine. And we’ve got two, four, and six routed to what would be the passenger side of the engine. It’s very important to have this routing correct. First off, that we’re not breaking these tubes, but second, we need the fuel to get to the cylinder at the exact time.

Just to recap, one of the most important things to take into consideration when installing this injector is the routing of the tubes. So let’s flip this injector unit over and look at what’s normally going to go over in the driver’s side of the vehicle for cylinders one, three, and five. Now, you’ll notice in order to get everything in the bracket properly and get it routed, we’re going to have to tuck the number three injector around behind the number one tube. So if you notice how I’ve got the tubes routed here, we’ve got three behind one. Now over on the other side here, for cylinders, two, four, and six, we don’t have to do anything special. They can all stay in their proper order. So once again, once we flip this thing over, the number three injector will get slid over like this and away we go.

You can see we’ve done a good job of lubricating it, installing it properly. Now we can go ahead and install our upper cover here. And once that’s actually installed, we’re going to remove these two little plugs right here. You see we’ve lubricated the fuel lines. Those are going to get slid in there. We’ll finish installing the throttle body, the cables, plug everything back in, and the vehicle should be ready to go.

So hopefully now you have a better understanding of what it takes to replace the fuel injector unit with this updated design on a 4.3 liter GM engine. Don’t forget to clean it. Don’t forget to lubricate it, and be gentle when installing this. So now that we’re all done, thanks for watching, and enjoy your new fuel injector.