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Discussion Starter #1 (Edited)
I have assembled different write ups and DIY articles to come up with the most complete LB7 injector replacement write up I know of.

Hope this is helpful for all LB7 owners!

Tools needed:

5mm allen bit, wrench, and ball end bit.
8mm allen bit or ball end bit.
Torque wrench
Basic set of metric tools
19mm wrench, stubby, crows foot.
Pick set.
Pry bar set and maybe a floor jack


Parts needed:

Here is a list of the parts you will need to do all 8 injectors

1. 8 LB7 fuel injectors, GM part number: 97729095


2. Install Kit - 8 Joined banjo washer pairs for connecting return lines to each injector,
* 2 Joined banjo washers for connecting the return line on each side to the head,
* 16 External injector o-rings,
* 8 Copper seat washers


3. 2 tubes of "Permatex Ultra Grey" RTV silicone sealant.



Getting Started:

Starting on the Passenger side you gotta remove All the tubing, intake, the FF bracket (there are 3 bolts holding it on and a 4th one just holding a coolant line to it) and the FICM.





The connectors on the FICM have tabs that slide up and down, for the top connector theres a tab on the top of it and you can pull it up untill the connector off. the bottom connector comes off the same. After disconnecting nearly all the engine wire harness you can pull it out of the way. and then start removing the FF ad FICM.















And disconnect the glow plug wire and remove the metal bracket connecting them all together.

 

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Discussion Starter #2 (Edited)
Remove the Keepers on the injector lines with a 8mm socket.





Then remove the injector lines with a 19mm wrench. If you plan on keeping some of the same injectors and injector lines then you should have a look at this post for more information on the corrosion buildup on the injector lines and injectors.





Next step is to remove the upper valve cover. There are tabs sticking out the upper valve cover you can use as pry points. The factory sealant is crazy strong. I tried using a floor jack and it would t budge it kept on picking up the engine.



You can pull the alternator off and use the bracket it for it as a fulcrum for more leverage against the valve cover.







Upper valve cover off

 

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Discussion Starter #3 (Edited)
To get the lower valve cover off you gotta disconnect and remove the injector wire harness. Its held down to two injectors with four 7mm nuts and two gold 10mm bolts. The 7mm nuts are permanently fixed to the harness so u don't have to worry about loosing them, just the 10mm ones u need to hold on to.







After Removing them You are now ready to pull the lower valve cover off. using a 5mm ball end allen bit really helps out, also having a variety of extensions helps to when you get close to the fire wall. Pulling the fender liner really helps out when trying to get the ones in the back on the driver side. The bolts ain't tight, in fact some of mine were finger loose...



With the lower valve cover off you can remove the injector return line. Be careful with these, try to use a regular 5mm allen bit and tap it in there the best you can because these bolts strip easily. I messed up two of them and i had to use channel locks to remove them.







Picture with the return lines removed.



 

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Discussion Starter #4 (Edited)
All the injectors have a bracket holding them in place, un screw them, they are pretty tight so make sure not to strip them with a 8mm allen bit.





To pop them out once the injector is loose give them a little twist first to make sure aren't stuck to the cup and then use a small pry bar to pop them out from the top using the bottom of the high pressure supply line on the injector as a pry point and the head bolt as your fulcrum. They should pop right out pretty easily. make sure to remove the copper washer from the bottom of the cup if it doesn't come out with the injector. be sure not to lose the steel button that rests under the bracket that holds down the injector, it usually stays in place, but make sure it doesn't go anywhere.



If the injector comes out with the cup, the coolant from the head will drain into the cylinder if you didnt drain the coolant first.



You can see the gunk built up on the injector that caused it to stick to the cup.





The Injector bore with out the cup in there







Make sure you get all the coolant out the cylinder by bumping the engine over a few times, itl make a huge mess but you gotta get it out somehow. To reinstall the cup clean up the locktite on the bottom of the cup and clean the insides real good and replace the o rings if you can. then prep the cup by using putting red locktite on the bottom of the cup where it begins to taper because that's where it seals with the head. and lube up the o rings with some vasoline or oil. Also clean the mating surface in the head where the cup contacts, need to get it very clean.

Be very careful when re installing it and make sure it goes in straight, you can put your finger in the cup and slide it into the bore ad make sure its lined up and completely straight. slide the cup in until the first o ring goes in and check to see if the cup is still going straight down the bore and push it in a little more. GM says to use a brass drift to drive the cup into the bore the rest of the way, you can use a 24mm socket put onto an extension backwards. The extension barely fits in between the valves and since its backwards on the socket it gives it a large flat even surface to drive the cup in. drive it in until its flush with the bore.
 

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Discussion Starter #5
Before putting the injectors back in you need to put on two new o rings

in the picture im pointing where the o rings should be





Re install a new copper washer at the bottom of the injector cup.



and install the injector with the clamp and torque it down to 37 ft lbs



Re install the return lines with new seals. Tighten the banjo bolts to 12 Nm or 106 lbin. Tighten the 12mm banjo bolt that goes into the head to 11 lb ft





Install the lower valve cover and tighen bolts in sequence to 10Nm 89 lbin twice



Install the injector harness and tighten the bracket bolts to 9 Nm or 80 lbin
7mm connectors to 2Nm or 18 lbin

 

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nice write up
 

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Discussion Starter #7
Put a bead of sealant to the bottom of the upper valve cover about 2-3mm wide and 1mm high and install the upper valve cover.



Tighten bolts to 8 Nm or 71 lbin in this sequence




Install injector lines and keepers



Now put the the FF and FICM back on and ur ready to do the driver side :U:







Thanks to mytmousemalibu (chris) for for giving me tips and hints on replacing the injectors :pals:
 

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i might need this one day!:drink
 

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Discussion Starter #9 (Edited)
There is one thing I will mention because I do not now if it is in there.

- Before you start, drain the engine coolant incase a injector cup comes out with the injector, causing coolant to pour into the firing chamber!

The coolant plug is on the passanger side at the bottom of the radiator.

BTW: I will buy any used injectors (Cores) That anyone wants to sell! PM Me for a price quote!
 

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Rode the Short Bus
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Nice write up. I too have an LB7, I am sure this will come in handy one day.

I just want to subscribe to keep up with it.
 

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Discussion Starter #12
Holy cow that looks complicated! Im not looking forward to that. I wish ours were like dodges sometimes. Thanks man i might need that in the future with my LB7.
It's really not that bad, you just take your time and do it step by step.

Don't try to rush it and you will be fine.

I hope I never need headgaskets though!! :booboo
 

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Is there a way to determine which injector is bad? I know I have at least one bad, it would be nice to know which side.
 

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That right there proves to me that I will never do it.... I will take to shop for sure!
 

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thats a lot stuff to do.....please o please o please dont make me do that!!!
 

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Rode the Short Bus
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I must be spending too much time in the office and not enough time in the field. I don't want to have to do it, but it does not look like a bad job. Actually I like doing this stuff and that looks like a good one to do.

When I was in college, I bought a Ford Ranger with the 4.0L V6, and when I got it home I noticed a valve cover was leaking oil (small job I know), but I decided I should repair it.

So the next day I went and got the parts and tore right in. Like I said, I just like doing that stuff (sometimes, preferably in a shop or a nice warm day, not cold and wet).
 

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definately a lot of work...anyone actually know why the lb7 are prone to injector failure?
the fuel system use to be different brands(bosch and some other one/s) for different parts and they didnt necessarliy work that well together now they are all bosh so they its all one system essentially...atleast thats what i was told
 

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All i have to say is *Bookmarked* lol
 
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