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How To Replace LB7 Injectors


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How To Replace LB7 Injectors
Injector failure is a common issue on LB7 trucks, and as the years go on more and more trucks grow out of the special service policy. The policy is for trucks that have less than 7 years or 200,000 miles on them after the date they were put in service. If your truck is within this coverage then take it to the dealership and have them replace your injectors. There is no $100 charge either.

You can get injectors from gm, Pensacola Diesel and other places.

The GM Remans are actual Bosch Remans and are about $350 from GM each.
The Pensacola ones are Reman’d by them and are $150 each.

Personally I use the Pensacola ones. There are arguments both ways but they are cheaper and show up to your door right away. They also carry a one year warrenty.

You will also need an injector install kit. These are $27 each from Pensacola diesel and do one side of the motor. You will also need either Right Stuff Gasket Maker or GM sealant. In addition I also like to replace the two gaskets for the banjo bolts on the FICM.

Here is the write up. Keep in mind this write-up isn’t quite done yet. Ill add more info to it and clean it up a bit when I get home and can actually look at a truck. Ill be sure to add more pictures. This writeup is far from done, But for now I put it up so a couple of people who requested it can see it.

1.The first thing you do with almost any project is disconnect the batteries just to be safe. You’ll need an 8mm or 5/16”. You will also want to put the hood in the service position. This only takes about 2 minutes and will make your life easier for any project when you’re under the hood. To do this, open the hood all the way then using a 13mm, remove the nut on the bolt that connects the spring to the hood. Do this on both sides, don’t worry the bolt will hold the hood up (usually don’t sue me if it falls on you) now carefully lift the hood as you remove the bolt then hold the hood as you walk to the other side to remove the bolt on that side. I find it easiest to support the hood with me head then remove the bolt as you will need both hands for the next part. Now stand the hood nearly straight up and down but leaning forward just a touch. Rest it on your head and using one hand bring the spring up and line up the hole, then insert the bolt and put on the nut. Now walk to the other side and repeat. You just made your injector replacement a lot less stressful.

2.Start by slightly lifting the truck and removing the front wheels with the 7/8 socket.

3.Now remove the fender liners by removing all of the body clips, Christmas tree plugs and wiring harnesses.

4.Now drain the radiator by removing the drain plug near the CAC tube. Removing the coolant overflow cap will drain it quickly if you have a good way to channel the fluid into a clean pail. I use an old driver’s side CAC tube. Once drained reinstall the plug and tighten. It does not need to be very tight; it is plastic and will break. The reason for doing this is so that you don’t make a mess when you remove the coolant lines later on.

Passenger Side Removal

5.Remove the intake from the truck using a 5/16 nut driver. The Box can stay it won’t be in the way.

6.You may also find it easier to swing the a/c condenser out of the way as well by removing the belt, then the 4 bolts using a 15mm then the two electrical connectors and then swinging it up and out of the way laying it onto the battery. This is personal preference and they are a little different between years.

7.Next remove the passenger side CAC Tube using an 11mm deep well. I loosen the clamp on the intake manifold side and the clamp on the CAC tube itself near the intercooler. This way the boot on the intake manifold is out of your way and the elbow is still attached to the Intercooler which makes realignment easier. Now remove the tube from the truck.

8.Now you can begin to remove the coolant lines. The only ones you need to remove are the heater lines. Start by removing the heater return hose from the aluminum heater return line. This is near the front of the motor by the belt tensioner.

9.Now remove the heater feed and return hoses from the hard lines attached to the motor leaving the rubber hoses attached to the firewall.
10.Now you can remove the aluminum heater return line using a 13mm, remove the nut that attaches it to the fuel filter housing adapter bracket and the bolt that holds it to the alternator bracket. Inspect the bracket where the line bolts to the alternator bracket. It has a tendency to crack and leak. I just TIG weld around the entire bracket to ensure it seals then pressure test it before reinstallation. Also while your down there unbolt the dipstick tube using a 12mm.

11.Now remove the bolt that holds the heater feed line to the fuel filter housing adapter bracket using a 12mm. While your up there you can disconnect the #5/#7 Injector wiring harness by first removing the grey clip and then disconnecting the harness. You can also disconnect the #1/#3 injector wiring harness using the same procedure.

12.Now give the wiring harness and yank to unclip it from the various lines that secure it. Also cut any zip ties holding it down to give you more room to work. You can also remove both connectors from the FICM by pulling out the clip and you pull the harness out of the FICM simultaneously.

13.Now using a 17mm remove the two banjo bolts from the FICM. Then using a 14mm remove the three bolts that secure the FICM and remove from vehicle and set aside. There are little white donuts that will sometimes fall out when doing this so keep and eye on them. Now unclip the wires from the FICM bracket and using a 12mm remove the 3 bolts that secure the bracket to the valvecover and set aside.

14.Now remove the fuel outlet hose from the fuel filter housing. Then unplug the WIF sensor and fuel pressure sensor wires which are located near the exhaust manifold. Then using a 12mm remove the two remaining bolts that secure the fuel filter housing adapter bracket to the valve cover and set the entire assembly aside.

15.Now you can proceed to the universal instructions below.

Drivers Side Removal

1.Remove the drivers side CAC tube. Now this can be a PITA. So if you want to make life easier you can remove the large blue silicone hose and the aluminum piece separately, however re-alignment can be tricky when putting everything back together.

2.Now remove the upper radiator hose, which is pretty self explanatory.

3.With that out of the way there will be some wires in your way that need some attention. Start by removing the power wire to the glow plug module. It’s a red wire that runs over to the module by itself. Its also the only wire over there that uses a 13mm socket to remove the nut versus a 12mm, so you should get it figured out. Now you can also disconnect the two big bale connectors and disconnect the harness from the clip that is holding it to a bracket. Now you should be able to swing that harness out of the way enough IIRC. You may need to disconnect the harness that runs to the A/C system, coolant overflow, and the alternator to get more slack but im not sure at the time of writing this. You will also need to unplug the connector that plugs into the pedestal where the bale connecters are fastened, next to the upper coolant pipe.

4.Now you will need to unbolt the big bale connectors from the pedestal they are fastened to using a 5mm allen tool. There is only one tiny bolt per connector. Now you can remove the pedestal using a 12mm to remove the three bolts that fasten it to the valve cover.

5.Now you can remove the upper coolant pipe I guess you would call it. To do this first remove the turbo coolant feed line, then remove the bolt that fastens the pipe to the thermostat housing using a 12mm. Next using a 12mm remove the two bolts that fasten the pipe to the valvecover. Now you can remove the pipe with a little gentle persuasion.

6.Now you need to disconnect the fuel lines using a fuel line disconnect tool. Once disconnected unbolt them from the valvecover and hold them out of the way with a bungee strap or something.

7.Now its time to remove the glow plug module. To do so. You will need to go in from the fender well and remove the nut that fastens the glow plug wire to the glow plug using an 8mm. Also remove the wire that is connected to the #2 cylinder glow plug, this wire is not connected to the glow plug module but will need to be moved out of the way later on. Now back up top you will want to remove the bolt that holds the wires to the valvecover using a 12mm. Next you will see two wires with blue sheaths and little black connectors. Disconnect both of them. Don’t worry about which one went where; you can’t screw them up when you are reassembling. Also disconnect the wires that rest on top of the module, and now all of the wires should be free from the module and you can swing them out of the way. To remove the actual module there will be two nuts to remove with a 12mm.
8.Now when you remove the module you will see the fuel line bracket is held underneath the module. This is a different bracket than the one you removed earlier in step 6. To finish removing this bracket use a 10mm to unclamp it from the fuel lines.

9.Now you can proceed on to the universal instructions below.

Universal On both sides This is the point where both sides of the motor are the same.

1.Now you can remove the PCV hose from the valvecover.

2.Now remove all 4 of the high pressure fuel lines using a 19mm wrench. Once loose give them a yank to pull them out of the valve cover. Take note of their position as they only fit in once place.

3.Now remove all of the little screws that hold the upper valvecover on using various 5mm allen tools to reach all of them. They can be a real PITA when they are in the truck. Try your hardest not to round one off. Now using a pry bar locate the tab on the valvecover near the valley and pry up on it using the fuel rail for leverage. This will separate it from the lower valvecover. Keep working with it until it comes off then set it aside for cleaning.

4.Now you need to remove the injector wiring harnesses. To do so use a 7mm to remove the wires from the injectors and a 10mm to remove the bolts that fasten the harnesses to the rocker shaft assembly.

5.Now remove all of the screws that hold the lower valvecover on to the cylinder head and set aside for cleaning. The rubber gasket for the lower valvecover is supposed to be replaced. However you can get away without replacing it. I’ve had mine on and off 3 times and it never leaked but they are cheap so you might as well do it right.

6.Now the fuel return line needs to be removed. It’s the gold line that is connected to the injectors. Use a 5mm to remove the banjo bolts from the injectors and a 12mm to remove the banjo bolt that runs into the head.

7.Now you can finally remove the injectors. You can either use the special tool or a makeshift way that ive found to work. But first you need to remove the bolt that holds the injector hold down to the head using an 8mm allen head IIRC. Now you can either place the special GM tool in the injector hold down then using a 15mm on a breaker bar and pull back on the tool to pop the injector out. Once its popped your good to go and you can pull it out the rest of the way by hand. Also just because its junk don’t beat it up, treat it with care. If it was damaged by you they wont accept it as a core. If the injector cup does come out with the injector don’t worry this is not a big deal, you just need to clean it up, put new o-rings on it, some fresh red loctite and then reinsert it using a wooden dowel of the same diameter and a rubber mallet.

Installation Tips

I do not remember the torque specs and such off the top of my head I will add them later on.
Clean the gasket material from the valve covers then apply a new layer just before installing.
Clean out the injector bores as much as you can before reinstalling.
Lubricate all o rings before reinstalling.


Sorry I do not have all of my pictures at this time. But with these few can show you where everything is. For now Im just going to pile them all down below the writeup. I will add the rest later and insert them after each step in more detail. Click them and they will get bigger.

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South Ga.
Only problem with pensacola remans is that they are unreliable and since LB7's are a PIA to change...I would buy mine from gmpartsdirect at a cost of 182 bucks...shipping/handlingis more but atleast they are GM/Bosch remans


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Ive never heard of any issues with them but im sure there are some.

Its only about $100 less to get them from Pensacola.

However GM Parts Direct is a nightmare to me. I never like to deal with them. Parts dont show up on time, parts get lost, and they are not good to work with.

Customer service is huge in my book and its the reason i dont do business with a lot of companys if i dont have to.
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Yes in my final version I'll add that but I'll tell you right now too.

7-15mm wrenchs and sockets.

Various 5mm Allen tools

8mm Allen

3/8" and 1/2" torque wrench

injector removal tool or a large punch

pry bar

scraper and/or die grinder with gasket removal disc.

19mm wrench or line wrench.

7/8" or 22mm socket for removing wheel

body clip removal tools for removing fender liners

And a fee other basic hand tools


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Ok I'm a virgin so dont laugh ....
Should I adjust anything while I have this thing apart ? It has fuel in crankcase oil but starts easy without smoking any suggesting... No lack of power either