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Duramax 6600 Welcome to the Internet's first Duramax 6600 diesel discussion forum for the LB7, LLY, LBZ, LMM, LML, LGH & L5P RPO code engines. Tips on performance, fuel economy, troubleshooting and more.

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  #1  
Old 04-29-2019, 07:40 AM
Vetman7 Vetman7 is offline
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Unhappy Yet another injector question...

I have a 2002 LB7, with 143,000 miles. I replaced the injectors the first time at 80,000 (Warranty replacement) and am assuming GM used rebuilt injectors. Now after another 50k I'm getting black smoke at the tailpipe at idle. No increase in oil level, or fuel smell in oil.



It's important to note that I have a Kennedy MegaFilter and have been using a mix of FPPF and Cetane booster since the truck was new. I'm puzzled WHY I need injectors again, as I thought particulates in the fuel was the culprit...


Anyway, here are my questions:
1.) I was told I could buy some time before injector replacement by using additional additives. The recommendation was to use Hot Shot Diesel Extreme. Any better ideas, or do additives at this point do nothing?


2.) I'd like to do the injector replacement myself, but need info on special tools for injector and cup removal and whether it's necessary to remove injector cups, or not...



3.) I figured I'd buy injectors from Kennedy Diesel, but are the tools available there as well as all the extra parts (lines, o-rings, gaskets, etc?)



Appreciate any help you can provide...
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  #2  
Old 04-29-2019, 09:14 AM
Kennedy Kennedy is offline
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There is not a lot of need for special tools to do these. 5mm hex driver bits for the rocker cover screws and things like that. We don't use any injector pullers so as long as the cups stay in things go pretty smoothly.

I have been running SAC type nozzles on my LB7 for probably 10 years now. In recent years they have been introduced for the street market as a cure for the blue smoke at idle. These were 45% over so I did custom programming to tame them down. Coming very shortly will be a SAC nozzle with stock delivery flow. They should not need any programming, but I do suspect that they will benefit from a good tune even more than the std VCO nozzle.
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Kennedy Diesel-owner
More than just a salesman-I use and test the products that I sell on a daily basis!
Superflow Lie Detector in house
2002 Chev K2500HD D/A CC Long LT 11.77@ 124mph at 7700# fuel only-e.t. needs help
2005 Chev K3500SRW D/A CC Long LT(SOLD)
2007 Chev K2500 Classic EC Short LT (Sold)
2012 GMC K3500SRW D/A CC Long LTZ Happy Birthday to me! Built 1 working day after my birthday and delivered 7 days later.
2016 GMC K3500SRW D/A CC short LTZ

Custom tuning in house using EFI Live tuning software!
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  #3  
Old 04-29-2019, 10:12 AM
Vetman7 Vetman7 is offline
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Thanks John. I'm actually running an EDGE HOT tune that I got from you. Will that work with the SAC nozzles or do I also need a reprogram?


Of course, all of this adds lots of expense, so back to my question about buying some time by using additives to restore some function to the injectors. Any chance this will help? I did the Injector Balance Test and found Injector #7 with a value of -6.8 to -7.0. All other injectors were within -2.5 to +2.5.



Thanks again for your help...
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  #4  
Old 04-30-2019, 12:20 PM
Kennedy Kennedy is offline
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As soon as I poo-poo the Hail Mary approach of dumping in a mega dose of some wiz bang miracle cure someone reports complete success That said, the VCO style nozzle is subject to needle steer and the blue smoke has been documented many times over as a 40-50k repeat with the late production injectors.

SAC 00 should be pure stock delivery so no absolute need for tuning, but I do have some tweaks that tend to improve operation. At that point I would move on from the Edge.
__________________
Kennedy Diesel-owner
More than just a salesman-I use and test the products that I sell on a daily basis!
Superflow Lie Detector in house
2002 Chev K2500HD D/A CC Long LT 11.77@ 124mph at 7700# fuel only-e.t. needs help
2005 Chev K3500SRW D/A CC Long LT(SOLD)
2007 Chev K2500 Classic EC Short LT (Sold)
2012 GMC K3500SRW D/A CC Long LTZ Happy Birthday to me! Built 1 working day after my birthday and delivered 7 days later.
2016 GMC K3500SRW D/A CC short LTZ

Custom tuning in house using EFI Live tuning software!
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  #5  
Old 05-21-2019, 08:06 AM
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Quote:
Originally Posted by Vetman7 View Post
I have a 2002 LB7, with 143,000 miles.

Anyway, here are my questions:
1.) I was told I could buy some time before injector replacement by using additional additives. The recommendation was to use Hot Shot Diesel Extreme. Any better ideas, or do additives at this point do nothing?

2.) I'd like to do the injector replacement myself, but need info on special tools for injector and cup removal and whether it's necessary to remove injector cups, or not...

Appreciate any help you can provide...
John covered your other questions well enough, so I clipped your original post so I could spend a little time with the above two questions...

We've been doing this diesel thing for a long time, and the question concerning the benefits of fuel treatment has been hashed and re-hashed many-many times. Here's what I think... Personally, I believe fuel treatment is worthwhile IF the treatment includes a cetane improver in the list of ingredients. Large fleet tests have proven that fuel economy is increased enough to pay for the cost of treatment. What's not easily proven is whether a treatment extends the life of fuel injection components... There's just no way to know for absolute sure - no positive proof either way. Can a fuel treatment clean parts of the fuel system, removing varnish or other stuff that can negatively affect injector performance? Maybe, but proof that shows it extends injector life is really hard to come by. A couple of anecdotal reports...

Industrial Injection dot com has been offering "screw-in" LB7 injector cups for some time now. I wrote about screw-in cups as a "I wish this existed" product many years ago. Now it's a reality. They're not cheap, but it would remove the angst over whether that excess pressure in the cooling system is due to a cup seal leak or a head gasket leak. You'd be surprised/horrified to read as many reports as I have from everyday LB7 owners about over-pressurized cooling systems in the days/weeks/months following an injector replacement in these LB7s - too many to be coincidence.

I've spoken to many long time Duramax mechanics through the years, both GM certified and independent shop mechanics about this very issue (cup seal leaks when/after changing injectors). About a third of them reseal every cup that had its injector removed. The rest don't reseal any of them unless they "see" the cup move when removing the injector.

I'm hoping to do a head gasket and Industrial Injection cup install later this summer. I want the engine to be as trustworthy as it was when bought new. Everything else in the truck is like-new...

My thoughts...

Jim
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  #6  
Old 06-18-2019, 02:19 PM
Vetman7 Vetman7 is offline
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Hi Jim,


Thanks, I appreciate your reply. I've tried the additives now for about 5k miles, and things are just getting worse (lots of blue smoke and very rough idle). Of course, you'll note from my original post that I've been running a cetane improver since day 1. So clearly that didn't prevent the injector failure issue. Since the injectors were warranty replaced initially by GM, I'll assume they replaced with the same, failure prone type originally used, -which now are also bad!. Since it seems changing injectors is definitely in my future, I'll look for an aftermarket set with better design (any recommendations??). Unfortunately, its a complex enough job that I don't want to do it twice because the cup seals are leaking. Do you recommend replacing all cups with the screw-in style and any idea of the cost? When I pull the injectors, is it obvious if the cups remain intact? Or can they leak even if all appears to be good? Appreciate any additional thoughts...
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  #7  
Old 06-19-2019, 07:57 AM
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Quote:
Originally Posted by Vetman7 View Post
Hi Jim,


Thanks, I appreciate your reply. I've tried the additives now for about 5k miles, and things are just getting worse (lots of blue smoke and very rough idle). Of course, you'll note from my original post that I've been running a cetane improver since day 1. So clearly that didn't prevent the injector failure issue. Since the injectors were warranty replaced initially by GM, I'll assume they replaced with the same, failure prone type originally used, -which now are also bad!. Since it seems changing injectors is definitely in my future, I'll look for an aftermarket set with better design (any recommendations??). Unfortunately, its a complex enough job that I don't want to do it twice because the cup seals are leaking. Do you recommend replacing all cups with the screw-in style and any idea of the cost? When I pull the injectors, is it obvious if the cups remain intact? Or can they leak even if all appears to be good? Appreciate any additional thoughts...
John (kennedydiesel.com) has a lot riding on the reliability of the injectors he sells. He may be exposed more than most fuel injection component suppliers because his sales effort has been concentrated on the web. The web doesn't take prisoners. I'd trust him if you're a do-it-yourselfer.

If you have someone else replace your injectors, I'd pin my hopes on them to select the injectors because they simply have to offer a warranty. Still, I'd do a little research before trusting my truck to an unknown (remember the web doesn't take prisoners).

I think we're in a better place, regarding injector durability/reliability, than we were some years ago. Just stay away from cheap knock-off imported parts.
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  #8  
Old 06-19-2019, 11:08 AM
Kennedy Kennedy is offline
Long Distance Crew Chief for BMDMAX
 
Join Date: Mar 2000
Location: Loyal WI US
Posts: 10,679
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Quote:
Originally Posted by Vetman7 View Post
Hi Jim,


Thanks, I appreciate your reply. I've tried the additives now for about 5k miles, and things are just getting worse (lots of blue smoke and very rough idle). Of course, you'll note from my original post that I've been running a cetane improver since day 1. So clearly that didn't prevent the injector failure issue. Since the injectors were warranty replaced initially by GM, I'll assume they replaced with the same, failure prone type originally used, -which now are also bad!. Since it seems changing injectors is definitely in my future, I'll look for an aftermarket set with better design (any recommendations??). Unfortunately, its a complex enough job that I don't want to do it twice because the cup seals are leaking. Do you recommend replacing all cups with the screw-in style and any idea of the cost? When I pull the injectors, is it obvious if the cups remain intact? Or can they leak even if all appears to be good? Appreciate any additional thoughts...

The SAC-00 injectors, a set of new OE supply lines a set of return line end seals, and a tube of ultra gray are the main components that you need.

Secondarily a pair of thermostats because you are already in there. Lift pump, secondary filtration, and FPPF Total Power fuel treatment for protection.

We stock all of the above most of the time.



Leave the cups alone. The only cup issues that I have seen is guys trying to wish away a head gasket issue or those that improperly sealed them after popping out during an injector job. I run the std cups in my 2002 at 80psi boost.
__________________
Kennedy Diesel-owner
More than just a salesman-I use and test the products that I sell on a daily basis!
Superflow Lie Detector in house
2002 Chev K2500HD D/A CC Long LT 11.77@ 124mph at 7700# fuel only-e.t. needs help
2005 Chev K3500SRW D/A CC Long LT(SOLD)
2007 Chev K2500 Classic EC Short LT (Sold)
2012 GMC K3500SRW D/A CC Long LTZ Happy Birthday to me! Built 1 working day after my birthday and delivered 7 days later.
2016 GMC K3500SRW D/A CC short LTZ

Custom tuning in house using EFI Live tuning software!
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