GM V8 Central Port Fuel Injection Replacement
This instructional video demonstrates a central port fuel injection replacement for GM V8 applications.
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 has got well over 300,000 miles on it already. And we’ve got a couple of stuck poppet valves on various injectors here. 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 today.
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. 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 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. 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 we read instructions it’s 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 a unit here in which way we’re going to route these injector tubes.
So now let’s remove the unit out of the box. As we take a look at this, and well it certainly looks much different than the original unit. Whereas originally the injector part of it was mounted up here in the plastic body. 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 wirings in here and some different connectors. This is a direct replacement unit for the previous design though. You also noticed 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 clean 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 generally 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. Once everything is released, now it’s going to be time to remove the entire unit. No, 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 was 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. That’s 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. 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 for a week later.
So we’ve decided to replace the complete unit here, but 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. So I’m using a little bit of a transmission assembly gel here. It’s 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 helping get a good tight seal once we install this down into the intake manifold. Of course, make sure 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.
So, once I removed 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, let’s take a look at installing a new injector unit on a V8 application, such as 5.7. VNR here. Now, once again, we’ve got the intake cleaned up a little bit, so it’s easier to see, but the Cassie on intake actually does have the firing order or the cylinder identifications here labeled inside the port. Now real life was going to be a lot of carbon dirt buildup. So you might not see those however, understanding where the firing order we have cylinders one, three, five, and seven on the driver’s side cylinders, two, four, six, and eight on the passenger side, certainly aids in the operation.
So, we’ve got our new bracket installed. Once again, it’s going to have a little bit of a movement here, but we’ve got this alignment pin to hold it in place. It’s going to give a little bit of flexibility. Now you can see in the injector unit here, the numbers are already embossed on the unit itself. However, we’ve added some stickers here for the aid of installation and the purpose os this video. So you can see exactly which injector comes out, where in which tube is where and how we’re going to install that. So we’ve got our new bracket in place. We’re going to gently squeeze these tubes, slide this kind of into place here. Now we’re going to begin our installation of the tubes. Now before we lock anything into place, it’s a good idea to get them kind of all started here. So we see that when we install number four, number two is going to have to cross over it. Likewise, on the back here where we install number six, number eight is going to cross over it.
As we go towards the front here, we’ll install number three and number one gets crossed in front of it. We’ll install a number five on the backside here and loop number seven, gently over it. Now it’s important to lubricate this when you’re actually doing this and make sure that your holes are good and clean, but once we’ve got our routing, correct. We can lock the main unit into place and we can go back and slide all of our injectors until clip into their home here. Once they’re all locked in place, should be all set to install the upper plenum and complete the job.
You can see we’ve done a good job of lubricating and installing it properly. Now we can go ahead install our upper cover here. Once that’s actually installed, we’re going to remove these two little plugs right here. 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 update design on the 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.