Anyone done their own LB7 injector replacement?

[Mark Rinker]

Well, the 2002 has been smoking for about 10K miles now, and last night I noticed it was really starting to get white and heavy after any idling. I am certain that it will soon be bad enough to cause oil dillution or unbalanced running, and am starting to plan for the future.

Interestingly, two quarts of cheap convience store brand-x tranny fluid added to a full tank of fresh fuel will make the white smoke go away for a few tankfuls, then the heavy idle smoke returns. I wonder why it has this real, yet temporary affect?

Scan tool shows three injectors way out of range...

At 280K, it might make more sense to drop a brand new LB7 complete with injectors into the truck, rather than spend $3500 at a dealership for a fresh set of eight. However, neither are in the budget - as cash is very tight.

http://cgi.ebay.com/ebaymotors/01-04...spagenameZWDVW

Has anyone done their own injector replacement? I am wondering how many specialized tools are necessary for the task. I have many friends willing to jump into this with me, but don't want to get in over our heads...your thoughts and advice appreciated!

[More Power]

I'll probably be pulling a set of heads on an LB7 sometime this fall. It's debatable at this point whether we'll remove the injectors, but we'll have the tools standing by. There is a special tool that is used to pop the injectors out of the heads, once the clamp bolt has been removed.

The cup seals have been a concern of mine. I spoke to a longtime Duramax mech this summer about injector replacement, and asked if he reseals all of the cups as a precaution, when doing injectors. He said no, unless the cup pops with the injector.

I asked him this question because of the numerous posts here through the years about cooling system problems and leaking water pump seals that appear sometime after replacing the injectors. A leaking (compression pressure) cup seal could be the result of a disturbed cup seal at the time of injector replacement.

For what it's worth, I spoke to another Chevy mech a few months ago who said he could R&R a set of LB7 injectors in about 2 hours. Said he's done a lot of them....

Jim

[Mark Rinker]

Its really strange how this thing will go from 'mosquito fogger' to only light grey smoke, only visible at idle with ATF in the mix. Maybe the ATF simply changes the combustion, eliminating the smoke?

The scan tool numbers don't lie - its obviously needing 3 injectors already after 110K miles on this set - but if I can keep the smoke down and it doesn't make oil, my plan is to run the truck until it develops a fuel knock. That means it will be relegated to local work (short boat hauls around metro, snow plowing) until that happens. The other two trucks will have to carry the long distance work in the meantime.

My hestitation at doing this myself, or letting a mechanic friend moonlight in his garage is recourse, if something goes wrong in only a few miles after the fix. Saving money on a set of injectors isn't worth the downtime or strained friendship if a problem arises.

However, as I lean over the fenders and look at the engine - this isn't exactly rocket science, now is it?

[madmatt]

I do'em here at the house all the time but I do have the injector removal tool here also. I'd have to see someone do it in two hours to believe it though. I've done a lot of them and w/o rushing myself, 6 is pretty standard. Go for it!!!!!!!

[Mark Rinker]

Matt - Thanks for the encouragement. Do you care to elaborate on how you handle the precup seals? Do you reseal each one routinely, or avoid disturbing them?

I have never seen a bare set of Duramax LB7 heads, it would be easier to visualize if I could locate a set to examine. That might be my first step in preparation for this wrench-fest.

[Duramaster]

Yeah, I have to agree with madmatt. If that tech is replacing the injectors in 2 hours I would like to see how big his pile of left over parts is! I see those come in now and again with various bolts and brackets missing!!!

[madmatt]

[QUOTE=Mark Rinker;242793]Matt - Thanks for the encouragement. Do you care to elaborate on how you handle the precup seals? Do you reseal each one routinely, or avoid disturbing them?

QUOTE]

I only reseal them if they're leaking, come out w/ the injector or I'm doing some "work" on them and I want them to be like new when reinstalled

[Jake99Z71]

Maybe he was talking about replacing injectors on a LLY. My local guy does it in about 8 hours.

[t-roy]

I did one injector (#8) last friday night. Overall, not a bad job at all. The hardest part was getting to the four 5mm allen head valve cover bolts at the rear. Pulling the inner fenderwell made it easier but not "easy". I did use the special injector puller tool but decided that it is not really necessary. You'll need the fuel line disconnect tools (available at napa) and I suggest an assortment of 5mm allen tools (t-handles, L-allens, long and short shank socket drivers with and without the u-joint, and ball drivers).

My injector cup did not pull out with the injector so I did not mess with it, but I did have a new one on-hand just in-case. I cleaned the inside of the cup with a shop vac and a small funnel. I also drained the coolant prior to pulling the injector to avoid filling the cylinder with coolant if the cup did pull out.

I was very leery of doing this myself. Now I realize it really isn't that big of a deal. Anyone with some wrench turning experience can handle this job.

Good luck!

[OC_DMAX]

MP wrote "The cup seals have been a concern of mine. I spoke to a longtime Duramax mech this summer about injector replacement, and asked if he reseals all of the cups as a precaution, when doing injectors. He said no, unless the cup pops with the injector."

When (not if) the injectors fail on my truck, I plan on doing the replacement myself. Over the last couple of years, I have slowly accumulated the special tools required to do the job via E-bay (substantial savings). This includes the cup removal tool and the injector extractor.

It is my understanding that mechanics are paid a flat rate to perform a task. So if the injector cups don't pop out, then there may be no need to replace. However, as an owner of the vehicle and not in any particular hurry to complete the task, I plan on pulling the injector cups and resealing them (just because I am suspicious of them). My plan is to do one bank of cylinders at a time (injectors and cups), this way if issues arise at least they will be isolated to 1/2 of the engine.

MP- if you do remove the head and replace an injector cup - how about documenting the task and making it an featured article on the website !!

[lb7lbz]

hey mark does your truck cut out if you hammer on it with the bad injectors? i was at the dragstrip for the first time last night and i knew something was off. i've been looking for bad grounds because it would cut out and the lights would flicker,well today it died on me several times had to get out and prime then it would run codes p0093 and p0094 small and large leak looks like injectors for me too.

[GordonMarks]

I would agree w/troy. anyone that has done much wrenchtwisting can do it. It helps to have a service manual. I had a list of steps that I got somewhere & I'll post it if I can find it.
Mark, you will probably want the gaskets & as someone else said, "a varity" of the 5mm allens to get the VC bolts. I also replaced some of the fuel hoses.
The removal tool makes it a whole lot easier! I checked the cups w/my finger(I did drain the coolant)& didn't have to replace. Of course mine only has about 100K on it. I suspect that the 2 pass.side ones that were bad were due to the engine sitting for an extended period3+yrs.)before I got the sub going.
I only did the pass. side & plan to do the DS soon. I have NO fuel in the oil but a noise that sounds like a tappet out of adjustment- the other side only had a couple out 5-6thou. They are not very far out of spec & there is NO smoke @ idle or any other time except when I "exercise" JK's ECM.

[More Power]

MP wrote "The cup seals have been a concern of mine. I spoke to a longtime Duramax mech this summer about injector replacement, and asked if he reseals all of the cups as a precaution, when doing injectors. He said no, unless the cup pops with the injector."

When (not if) the injectors fail on my truck, I plan on doing the replacement myself. Over the last couple of years, I have slowly accumulated the special tools required to do the job via E-bay (substantial savings). This includes the cup removal tool and the injector extractor.

It is my understanding that mechanics are paid a flat rate to perform a task. So if the injector cups don't pop out, then there may be no need to replace. However, as an owner of the vehicle and not in any particular hurry to complete the task, I plan on pulling the injector cups and resealing them (just because I am suspicious of them). My plan is to do one bank of cylinders at a time (injectors and cups), this way if issues arise at least they will be isolated to 1/2 of the engine.

MP- if you do remove the head and replace an injector cup - how about documenting the task and making it an featured article on the website !!

OC,

Will do. Like you, I'd feel better knowing the cups have been re-sealed when R&Ring the injectors or when replacing the cyl head gaskets for a coolant overpressure problem (and there's no obvious gasket problem). I also plan to visit a local engine machine shop that does all the cup resealing for the local GMC dealership (when the dealership R&Rs an LB7 cylinder head) to get their advice and instruction. The engine shop is the same one I used to rebuild the 6.2/6.5 diesels I've had rebuilt since the mid 90's.

Jim

[Mark Rinker]

Strange thing about the 2002 in question - despite the stinky exhaust, the truck has never run stronger or faster. Power is fantasic, mileage is good.

[MFritch]

Well, this is a good thread for me. I have a 2002 GMC 2500 HD Crewcab with the Duramax and Allison. I am also running a VanAaken module at 110 hp. I’m at about 190,000 miles. I’m noticing a slight decrease in performance, a bit more smoke on acceleration and there is a bit of a rise in my transmission temperatures in the last 30,000 miles. The fuel economy isn't bad because I got nearly 21 mpg last weekend on a run from Sandy, Oregon to Chico, California. Given the mileage I'm beginning to wonder if a set of injectors and a transmission R&R are in order. I have not run a check on any engine codes yet. Does anyone have a suggestion for a tester that I can buy to check the engine codes? Is there a preferred service manual? I'm not afraid to take on the injector swap so I'll just keep listening here for now. I look forward to hearing what any of you have to share.

[More Power]

I like the Diablo Predator for reading trouble codes and looking at several dozen different real-time engine data.

The factory service manuals from www.helminc.com are what I use.

Jim

[oneton]

I was going to start a new thread but since this one is already talking about my issues I'll post here. My 02 is smoking alot at idle, I've got a 185,000 miles on the clock so would this be covered under the extended injector warranty? I'm not making oil and performance is fine but it'll smoke real bad when kicked into passing gear. Something that it didn't do when she was new.







Thanks
David

[DmaxMaverick]

I was going to start a new thread but since this one is already talking about my issues I'll post here. My 02 is smoking alot at idle, I've got a 185,000 miles on the clock so would this be covered under the extended injector warranty? I'm not making oil and performance is fine but it'll smoke real bad when kicked into passing gear. Something that it didn't do when she was new.







Thanks
David

If the injectors are the problem, they should be covered.

[oneton]

Thanks, looks like it's time to make the dreaded trip into the dealer then.








David

[DmaxMaverick]

Thanks, looks like it's time to make the dreaded trip into the dealer then.








David

Good luck!!

When you do, be sure to have all fresh filters and up to date service.