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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!

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
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2. Install Kit - 8 Joined banjo washer pairs for connecting return lines to each injector,

3. 2 Joined banjo washers for connecting the return line on each side to the head,

3. 16 External injector o-rings,

4. 8 Copper seat washers

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5. 2 tubes of "Permatex Ultra Grey" RTV silicone sealant.
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Getting Started:

Start by removing the passenger side wheel.

Then remove the inside inside fender (Black plastic)

Then drain the coolant from the radiator by removing the drain plug on the bottom passengers side.
(This is necessary in case an injector cup comes out with an injector. - If this happens and the coolant is not drained, you will fill the cylinder with coolant. Draining the coolant first insures that this won't happen!)

Note: when you take the plug out be sure to have something to direct the coolant into your bucket, because it will shoot strait towards the rear of the truck like a garden hose. :eek: - Expect a mess!
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While your down there, unhook the big Blue turbo intake hose from the inner-cooler buy loosening the 10mm nut on the clamp and pulling the hose off.

Next, unhook the Turbo intake hose off the top of the engine and wiggle it off and set it aside.

Starting on the Passenger side remove all the tubing, intake, the fuel filter bracket (there's 3 bolts holding it on and a 4th one just holding a coolant line to it) and the Fuel Injector Control Module (FICM).

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The connectors on the FICM have tabs that slide up and down to disconnect them. For the top one, pull up and towards the drivers side on the tab, and it will slide the connector out of the FICM. Pull down on the bottom connector and it 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.


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Disconnect the glow plug wire and move it out of the way. (Some LB7's have a wire that goes to each individual glow plug. - These will all have to be removed.)

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Remove the Keepers on the high pressure fuel lines with a 8mm socket. (Or Phillips screw driver)
 

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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 article for more information on the corrosion buildup on the injector lines and injectors: http://merchant-automotive.com/tech/lb7line.pdf

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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 very strong. I normally use a long socket against the bolt head that is down by the exhaust manifold, (circled in Red in the picture below) and use the socket as a pry point for a screwdriver, prying up on the lower tab of the valve cover.

(Disregard the bottle jack!)
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Upper valve cover off

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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 you don't have to worry about loosing them. Hang onto the 10mm ones!

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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.

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With the lower valve cover off you can remove the injector return line. Be careful with these because these bolts strip easily. - I like to use the combination of a vise grip around the head of the bolt, and a star wrench to break the loose if they are really tight.

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Picture with the return lines removed.

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All the injectors have a bracket holding them in place, unscrew them, they are pretty tight so make sure not to strip them with a 8mm Allen bit.
 

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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.

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If the injector comes out with the cup, the coolant from the head will drain into the cylinder if you didn't drain the coolant first.

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

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The Injector bore with out the cup in there

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To reinstall the cup clean it up real good and replace the o rings.
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.
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.
Valve adjustment:
I recommend checking your valve lash while you have the valve covers off, especially if you have a lot of miles on your LB7.

I will not go through this process in this write up, but Merchant Auto has a very informative DIY on valve adjustment.

See it here: http://merchant-automotive.com/tech/valveadjustment.pdf



Injector Install:

Before putting the injectors back in you need to put on two new o rings

In the picture I'm pointing where the O-rings should be

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

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

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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

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

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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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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.

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Tighten bolts to 8 Nm or 71 lbin in this sequence

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Install injector lines and keepers

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One thing to take note of upon reassembly, is to seal the top of the high pressure line fitting. On the injector end. This keeps dirt and debris from building up in that fitting, and dumping inside of the injector the next time you have to remove the HP lines. See red circle in pic.

I also like to wipe the excess RTV silicone off around the upper valve cover to make it look neat. Red point in pic.

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Now put the the fuel filter and FICM back on and you're ready to do the driver side :D

Driver Side:

The driver side is the same, only with more "stuff" in the way. First remove the inner cooler tube;
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Next remove the upper radiator rubber hose.

Remove the metal radiator crossover tube (Red arrow in picture) by taking the (2) 12mm bolts out of the valve cover, and the (1) 12mm bolt out of the thermostat housing, then carefully slide it out of the thermostat housing. (It has a rubber O-Ring to seal against)

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It might help to unbolt the A/C pump (4 bolts) and slide in forward slightly
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One of those bolts is hidden by the large bale connector;
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Unhook the main wiring/engine harness bail connectors buy squeezing the 2 tabs (circled in Red above), and lifting up on the Grey handle (circled in Blue)

Then remove the bail connectors from the bracket that holds them by removing the Allan bolt that holds each one in place.


Next, Remove the (3) 12mm bolts that hold the large bale bracket to the driver side upper cover, here again, no good pics.

Using fuel line disconnect tools, (Or in my case a Leatherman Wave milti tool :p:) disconnect the fuel lines where they go over the valve cover by the drivers firewall. First remove the spring clips, then the lines themselves;
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The above pic shows the Glow Plug Module. We completely removed that from the truck, next time, I will disconnect the wires, to the point where it can just be moved out of the way;
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At this point, you should be able to remove the high pressure lines (clips first);
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Injectorreplacementdshplineson.jpg ]

From this point, the driver side is just like the passenger side. Just without as much room to work. Don't forget about the glow plug wire;
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That's about it, obviously reverse the above steps to reassemble. Prime the fuel system, fill the radiator, remove the bleed screw to get some air out;
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Reconnect the batteries, and fire it up :D

Don't be surprised if you have to keep alternating from pumping the hand pump by the fuel filter, to cranking the starter. you'll get it started eventually!

You are welcome to ask questions or ask for advise as needed.

Good luck guys!
 

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Discussion Starter #7
In all seriousness, it is not nearly as hard as the write up makes it sound.

I went to a lot of detail, but it ain't hard when you start taking things apart.
 

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Hey Titus, i just ordered LDS injectors from you yesterday and plan to do this job myself. Is this write up still comprehensive? Is there anything to add to it or is it pretty much all inclusive? any special tools that i cant live without?

Also, what will i need to do when filling back up with coolant? Any special steps here and how much will it normally hold? Just so i know how much to buy.

Thanks, looking forward to getting things torn up. It looks like the injector part of it is fairly easy, just getting to them takes up all the time
 

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Discussion Starter #9
I think the write up covers everything..... and you do not need any special tools.

You will need about 4 gallons of coolant to refill the radiator and reservoir tank.

Take the bleed screw out when you are putting the coolant back in, until you see coolant coming out then tighten it down and fill it the rest of the way up. (See the last picture.)

Good Luck!
 

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Great write up....wish i would have thought about looking for this before i took my truck to the dealership to have this done. Cost me 5800.00, OUCH!!

Are there any additives that can be used to help prolong the life of the injectors?

Thanks
SC
 

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Is the sealant not needed when installing the lower valve cover?
 

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Discussion Starter #12 (Edited)
Yes there are a lot of additives available.

The question is if they will increase the life of the injectors enough to pay for themselves.

I personally do not think any additive affects the lifespan enough to be worth it (This is going off a lot of feedback from many of our customers) but if I would decide to use any additives on a regular basis it would be Stanadyne diesel fuel conditioner.

Additive and extra filtration are proven to help, but I have spoke personally with people who used both since day one and their injectors still went bad at 100K.

- Titus
 

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Thanks for the info....I guess it's safe to say that the injectors will only last for around (roughly) 100k miles no matter what one does.

Thanks
SC
 

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Okay great, one more thing, when adjusting the valves, what all has to come off the front of the truck? Fan shroud only or will i need to remove the radiator, etc in order to get to the Balancer. Also, seems like a good time to change the serpentine belt while im at it
 

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Discussion Starter #16
You should only have to remove the fan shroud and possibly the fan.

Search google for water pump replacement instructions, and you will find some pictures and instructions to remove the fan.
 

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Any recommendation as to total time required from start to finish for all 8 injectors to be replaced?
 

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Hey Titus
I have ordered my injectors from you and they are supposed to be here next Thursday. Thanks for this write up. Yesterday I got the injectors off the passenger side and most of the stuff off the drivers side down to the valve cover. All I have to say is HOLY COW what in the heck is all that wiring for? It is one huge spaghetti mess. But seriously this is a job that anybody with a little mechanical knowhow and these instructions can do. I am not working steadily at it and I figure it will take me 4 days to do the job. I have already found several items that the stealership did wrong including not hooking up some gizzmo under the wiring on the drivers side. I have to find out what it is so I will probably be lurking around the site latter. Thanks again
 

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If the gizmo is located under the bracket for the bale connectors I believe that's the barometric pressure sensor
 
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