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How To: Change LB7 Injectors With Pictures!!!

556K views 127 replies 55 participants last post by  C-Power  
#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
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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
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3. 2 tubes of "Permatex Ultra Grey" RTV silicone sealant.

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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.

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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.

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

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#58 ·
if you dont mind me askin for how much?

he helped more then i can say, i bugged him so bad w/ questions, i really felt bad, im goin to his place on friday so he can look at my FICM, so ill get him all the injectors then,

he hasnt touched my truck its all been on the phone but seriously, i've never had any one help me the way tony (horsehaulin) did, he's a great dude, i guarentee you'll get your injectors fast and w/ no hassle from him,
 
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#60 ·
got it, yeah tony has answered every question i've had, i think yesterday tryin to get it started i called him pri 5-10 times in a couple hours haha, while he was at home, i felt terrible but he is the person i call if i cant figure it out haha,
 
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#61 ·
yeah i probably would have re-used my bottem gaskets if the previous owner would have replaced them when he did or got the injector job done...instead they just used a whole lot of sylicone...it was holding well with no leaks, best to my knowledge but id rather do the job rite and just use gaskets period new or used.. but preferrably new tho..as i will be duing..
 
#62 ·
just did mine. driverside sucks balls... only because of the electronics and the valvecover bolts are hard to reach in some spots
 
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#63 ·
i cheated, on those hard to reach back ones, i got bolts w/ the same thread and same length, and used them so i dont have to worry about an allen head any more,
 
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#64 ·
did any of you guys have to have your key on to get it to prime?

maybe it was just a miricale or maybe it was just time, but my buddy came over and we started to prime my system he suggested maybe i need hte key on so i turned it on and then it primed in no time,
 
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#66 ·
to the run position and then my primer got tight, then i cracked the 2 rail lines and rolled the engine over, while priming w/ the hand pump, got fuel rollin there, tightened the fuel lines and hit it w/ ether and she took right off,

it could have been a coinsidence that it was when we turned the key on, i have been tryin to prime for a week now, but not at long intervals, so i think since my buddy was there i had some fun and it took off!

EDIT: I KNOW WHY IT TOOK OFF AND PRIMED, i put the correct thread size and length bleeder in there, well i broke my bleeder screw so i just put an o-ring on a bolt and put that in there, the first one was too small the second one was exact,
 
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#67 ·
cool might need this some day, hopfully not too soon though
 
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#68 ·
great thread, sorry i kinda ruined it w/ my problems, but if some one runs into priming problems my story may help haha
 
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#70 ·
i would like to add this since i was dumb and didnt do so,

change your fuel filter when you do them, i was holding off but now i still have alot of smoke, and it lopes real bad, so im assuming its my fuel filter, or the diesel shop messed up and gave me the wrong good injectors, so ill do that and see what happens, this truck will not win!
 
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#71 ·
is it okay to re-use the supply lines from the rail to the injector?
 
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#72 ·
the metal lines? yes, i've never heard of any one replacing those, unless you bend it and break it
 
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#74 ·
ok, so heres the update.........

tech II said #6 isnt even close to right, it was sticking open,

so the place i had test them Daves Diesel out of Angola, Indiana had one of thier guys that lives 10 min from my dads come out to look at it, and tear into it, he's the one that tested it w/ the tech II, well once in there he said it was b/c i had a loose injector hold down, sounds fishy, im goin there tomorrow mornin to figure out that injector and get new return line seals
 
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#77 ·
subscribed
 
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#78 ·
SHE RUNS! i changed out that injector #6,

actually it was kinda wierd haha, for 1 i felt like a pro!

2) i wasnt gonna change the cup b/c i figured it was seated or it would have pulled w/ the injector, boy was i wrong! i slid the new injector in and tapped it down into its spot, well i was tryin to teach a little kid some mechanic skills, and i was explaining stuff to him and i got to explain the ping you should hear when its seated right, so i rushed and forgot to put the hold down on haha, so i had to pry out the injector i just put in, and THE CUP CAME OUT! im kinda glad i did that now haha, that cup would have leaked for sure!

but i put a new cup in and went from there, only took about 3hrs of workin to change that injector and put the whole driver side back together! not bad i figured!

only sucky thing is i had to pick one of mine that were tested and werent as good as the other 4 of mine. so i have a bit of a haze again but im not worried about it, its mostly only noticable at night,

but my coolant system doesnt pressurize so that means my 5 cups i pulled was my coolant problem!

if any one has any ?'s on how i did anything or what to do let me know, im easy to talk to haha,
 
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#80 ·
at first before i tore into my truck i had smoke at idle, and my coolant system was pressurizing, b/c the guys that did it before me didnt seal the cups, when i pulled my injectors, a month ago, i pulled out 5 cups! i put 5 new cups in w/ locktight 272, 4 of them sealed, the 5th one didnt, and it pulled out when i pulled my #6 injector,

so i put a new cup in w/ more locktight and now aside from the light haze my truck runs great!
 
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#82 ·
Doesnt seem as hard as ppl make it out to be. Looks like me and my dad could do this at the truck garage
 
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