Replacing Duramax LB7 Injectors 01-04 tips and hints
 

I am in no way an expert on this stuff, i just thought it would be nice to document this and share me replacing my injectors with yall. These pictures are on the passenger side, but both sides are the same, driver side a little longer because the bolts are harder to get to. when you get parts you might see some supliers sell a "complete" kit for injector install, you must make sure that you get the injector return line seals too.


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

Getting Started:

Starting on the Passenger side you gotta remove All the tubing, intake, the FF bracket (theres 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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Remove the Keepers on the injector lines with a 8mm socket.

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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 post for more information on the corrosion buildup on the injector lines and injectors.

https://www.dieselbombers.com/chevy-...r-service.html

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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 crazy strong. I tried using a floor jack and it would t budge it kept on picking up the engine.

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

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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 injecor 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.

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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. The bolts aint tight, in fact some of mine were finger loose...

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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.

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Picture with the return lines removed.

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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.

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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 didnt 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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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.

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

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

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and 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 tighen 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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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:
http://www.duramaxdiesels.com/forum/...ead.php?t=4824

Nice job so did you going with larger injectors?

still stock ones :(

wish i had the money for bigger ones

that is alot of work:ouch: but good job:5:

Yikes... Nice work/write up Danny

question
 

did all your injector tube's come out when you pulled out the injector? or if they didn't come out did you just leave them in and not worry about it?. GM has a tool for pulling the injectors and the injector cups did you need that?

if they didnt come out just leave them there. its a real pain to clean the mating surface of the head where the injector sleeves meet up. the one i pulled out came out because the injector got stuck to it and did not want to let go.

Did you use any sealant under the lower valve cover?

You mentioned you did under the upper...but nothing about teh lower.

Excellant write up and pics



.

the lower valve cover uses a rubber seal to seal it up. They are sometimes reusable, depends on how they look. i have had no problems using the same rubber seal 3 times when doing my injectors, the only hard part is getting it to stay on the lower valve cover. I used vasoline and make the rubber seal stick to the lower vc so i can install it.

Sweet write up Danny, that helps a lot! Looks a lot less intimidating than I thought.

If I drain the coolant out my radiator will that stop coolant from going into my cylinder?
What would I do if I did get coolant in my cylinder?

if you get coolant in the cylinder bump the engine over with the starter go get the coolant out. make sure to cover up the hole with lots of rags.

most of the time yes draining the rad helps

exellant thread danno i am going to be doing my new dmax soon with larger injs now i dlont have anything to worry about it seams simple

if its a new dmax u it should take a few hours to swap injectors, no need to pull the valve covers :U:

its an 01

have fun :D

thanks haha

Hi, new here. Found the site by doing a search on Duramax injectors.

2500HeavyDuty,

Couple of questions on this excelent post.

Have a 2002 Duramax. Injectors were replaced at 77k miles, and 160k miles under warranty. Now have 210k miles and this time I get to pay someone else to do it or do it myself. Reading your post, I feel pretty confident that I can do it myself, as I spent about 7 years as a GM mechanic back in the 80's.

So here's what I'm not sure about.

a) is there a parts list for this job... what do I need besides injectors?

b) I see several folks talking about using bigger injectors. Is there any advantage to this besides more power? Will they last longer? My Dmax has been an excellent truck and other than this issue, I have no complaints. I use it to tow a 10,000 lb boat, a 16' cargo trailer, and a 5,000 lb boat. I love the truck and want to keep it till it falls apart or 300,000 miles... whichever comes first, LOL, and my injectors seem to last 60k-80k miles which means I'll probably be doing this again. My truck is bone stock and does everything I've asked of it, so not really interested in installing different injectors unless they'll last longer.

Thank you for the post!!!!!

For the Parts list you will need injectors, a set of copper washers, O-rings (the washers and o rings should some with the injectors), injector return line seals (eight injectors ones and two for the heads), The rubber gasket for the lower valve cover is typically re-useable, a bottle of silocone sealent for the upper valve cover.

If the cups get pulled out you will need two new orange o-rings and special sealent to reseal it.



Larger injectors will help you get in more fuel in less ammount of time and require less timing. Its a good upgrade for people who want to go to the next level in performance, but fwiw if your are not looking to make alot of power then the stock ones are fine.

if it helps you can find a shop or company that will sell you injectors with a one year warrenty, and dont buy from pensacola.

as for longevity keep ur filters clean

Should I buy GM injectors or is there an aftermarket version available?

i bought my injectors from the dealer, for you they would be 350 a piece. maybe one of the vendors here can get you them at a better price that are new with a 1 year warrenty.

Nice work Danno.:tu:

FWIW, I found them from an online GM dealer for 201.25 ea. I've purchased stuff from them before, so I know they're legit.

Still searching to see if I can find them cheaper.

thank you much for your help.

Nice write up. I just got done doing two in my truck.

well this is my 5th time doing it now :jump:

cause i pulled my heads off

Rock on :rocking: Your gonna be able to do these in your sleep.

Wow.. that was something else. Makes me want to try it. I just got back from the dealer and they told me I need them changed (the second time) at a cost of 5000.00. I am three months over the warranty. Just got off the phone with gm but i know where thats gonna get me.

EXCELLENT job on those pics and instructions!!!

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Now where do I get cheap injectors ? :pca1:

i went with pensacola injectors and ended up going through 3 sets before i forked the money over for brand new ones from the dealer, long story short i should have went and bought new ones right away.

the injector lines are a pita to clean the corrosion is caked on there.

the driver side will give you the most trouble, cause of the firewall, having alot of extensions and allen wrenches will help. alot of stuff can be moved anf pushed around to give you more room

I'm talking to a guy here in Central Cal said the same about Pensacola, first thing he said when I told him I was looking for injectors.:tu:

yeah DONT get Pensacola injectors, they are nothing but trouble, and when it takes over 8 hours of work to do injectors it gets ond real quick


if there was any confusion from my earlier post

Well I did mine about 2-3 weeks ago. That's some serious work! Truck runs great and I seem to have lost my James Bond smoke screen.:jump:

Got brand new GM injectors for $201 each. Don't want to post link since I'm sure they aren't a paid advertiser on this site.

well whoever you get them from thats a smokin deal.

did you have corrosion on your injector lines?

Got them from a GM dealer who has an online website. They have some pretty awesome prices. I bought the injection unit for my wife's GMC 1500 w/5.7L from them a year or so ago. Ethanol screwed it up. They were $400-$500 les than any where else I could find. Funny enough for the guys from central Calif, they are in the SF area. Want to say Santa Clara but I forget.

No corrosion on the injector lines. My injectors were replaced under warranty twice. 2nd time they replaced at least 7 of the lines. Thought it was all 8, but when I replaced the injectors this time, 7 of the lines were shiny "chromish" looking, but the line on #3 cyl was dull greenish color. ???

yeah the original lines were dull green, i just bought some brand new ones and they look like they were made out of platinum... or they should be cause of what i payed for them :mad3:

I am currently tearing down my '01 LB7. When I removed the upper valve cover, I found most of the fuel inlets to the injectors caked in crud. One was so caked, I'm sure there was NO fuel getting to the cylinder. Is this a sign to replace the injectors? (obviously the fuel filter died at some point in the truck life)