# LB7 duramax injectors



## jb1390 (Sep 23, 2008)

My truck has started smoking at idle, I think it's been slowly getting worse. I am curious of someone with EFI Live (is it possible to use this software for injector diagnosis on multiple trucks???-forgive my ignorance) or a scanner could help me check the balance rates. Also, if anyone has access to a database that would show previous warranty work, I am curious if the injectors have ever been replaced under warranty, and at what mileage. 

I don't have any fuel in the oil, so I am pretty much ignoring it for the time being. Fuel mileage seems about the same as it's always been-right around 17 mpg with 285's and a flatbed dump (seems about right for the configuration). Plenty of power, just have the idle smoke, and sometimes a little surging at idle. 

Right now it's not a huge deal to me, I'd just like to know if I need to prepare for the job at some point in the future, so I can save some $$ and get parts prepared, etc. 

I also have some seafoam that i will try running through at full strength when I change the fuel filter, I'd like to, if possible, get balance rates before I try it, and then compare them to afterward.


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## plowguy43 (Jan 2, 2008)

PM me your VIN and I'll run it to see if its been repaired at a dealer. If injectors were done by a mom and pop shop it won't show up (obviously).


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## Mark13 (Dec 3, 2006)

What are you noticing for smoke at idle?

If it's a whitish smoke I'd be concerned. My lbz has a blueish/gray haze on idle, usually can't see it unless the light is just right.


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## jb1390 (Sep 23, 2008)

Mark13;1530076 said:


> What are you noticing for smoke at idle?
> 
> If it's a whitish smoke I'd be concerned. My lbz has a blueish/gray haze on idle, usually can't see it unless the light is just right.


I think it's a light gray, with possibly a bluish tinge to it. Could be burning oil too...I just know that injectors are a likely culprit and figured that's as good a place to start as any. It definitely is not a pure white smoke like my old 89 7.3 IDI had when it was trying to start.


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## R&R Yard Design (Dec 6, 2004)

Run some hot shot secret in the oil and see if it stops. If it does then start saving for the work.


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## plowguy43 (Jan 2, 2008)

All 8 Injectors were replaced 1/31/2005 @ 74,974 miles. 

Other then that its had a instrument panel trim panel replaced (9/24/2002 @32k), PCM Reprogram (7/22/2003 @54k), Tailgate support cable recall (10/18/2004 @71k), and Fuel Filter (2/13/2006 @87k)

Hope this helps!


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## jb1390 (Sep 23, 2008)

So assuming no other injector work, it's approaching 100k on the rebuilt units. I think that is the approximate expected life cycle correct?


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## 2COR517 (Oct 23, 2008)

Do these injectors ever hang open?


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## jb1390 (Sep 23, 2008)

I think that they do, and that is shown on the balance rates, because the computer adjusts to correct the amount of fuel actually being delivered. One of the major failures though, is a cracked casing that lets fuel down into the oil. At least I don't have that, so I think i have some time. 

Still wondering if someone in the CT/RI area could give me a hand checking the balance rates.


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## bowtie_guy (Jan 1, 2004)

Deff sounds like you should check balance rates. Anyone with EFI life can help you with that as you don't lock a vin in when using the scan side of the program. 

I've done it on LLY and LBZ trucks. 

If checking GM considers +/- 4 in neutral and +/- 6 in drive allowable.


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## carkey351 (Oct 18, 2010)

another possible cause of white smoke at idle is a bad FPR or fuel pressure regulator. its located in the valley on the injection pump. not the most fun to change but they are cheaper than injectors! if you balance rates spec out it may be worth some time to test that part out. either way its a duramax and i'd just keep driving it until it gets worse, that way you can better identify the problem. I drove mine with a bad FPR for about 7 months and probably could have gone longer...


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## Dr_Goodwrench66 (Nov 3, 2012)

2COR517;1530195 said:


> Do these injectors ever hang open?


Yes they do, followed by lots of white smoke and injector hammering that sounds like a rod knock!

Sounds like typical LB7 injectors to me. Get the balancing rates checked as mentioned. Also ramp up fuel pressure to 160MPA and see if actual matches desired...


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## 2COR517 (Oct 23, 2008)

I have seen the damage from an injector hanging open on a PowerStroke. Cant even use the block for a core


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## leolkfrm (Mar 11, 2010)

glow plugs and injectors are covered for 200,000 miles, not sure if they tagged a time frame....had my 2003 plugs replaced for free last winter at the dealer


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## jb1390 (Sep 23, 2008)

7 years........so no longer covered. 

Still wondering if anyone in my area has EFI Live and can help me check my balance rates........


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## trouble454 (Oct 8, 2008)

I have had a loose fuel filter or water in fuel sensor cause white smoke and a surge at idle on my 2003 LB7. I have also had the fuel filter head seals cause a slight air leak making for white smoke at idle and a slightly longer crank time before it would fire up. Simple things to check and sure alot cheaper than injectors.


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## Dr_Goodwrench66 (Nov 3, 2012)

jb1390;1530815 said:


> 7 years........so no longer covered.
> 
> Still wondering if anyone in my area has EFI Live and can help me check my balance rates........


I have EFI Live and a Tech 2 if your up for a drive!


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