[ry57pont]

my 03 duramax seems like its smoking too much at idle, it has 108k on it now. The injectors were replaced at 30k. anyone replaced the injectors? would a good cleaning help. Thx - Ryan

[Txbobcat]

I am not a diesel guy but I put seafoam thru the brake line in my truck fighting a misfire. After taking it to 3 mechanics that couldnt find anything wrong. 2ounces and five minutes it was fixed.

[Cammer-6]

most likely one or more of them is shot
have you had an injector balance test done?
you need good fuel and a better than stock filter
these are fussy! ask me how I know.........
and FYI those injectors are a PITA to replace
over $3k at dealer

[Hammertime Mike]

80,000 on a set of injectors, your getting into the failure range. Pricey and complicated to do. Check your oil [smell it]to make sure the diesel isn't getting in there. I'm nursing my 01 right now. I'm changing my oil at 3,500 instead of 7,000 until I can afford to dig into the injectors.

[Cammer-6]

bought an airdog system with transfer pump and extra filters
it seems to help but have gotten one code after pulling loaded for a couple hundred miles
Im also using a super chips programmer set on stage 2(lots of fun)
another option is to replace one bank

[ry57pont]

http://www.efilive.com/

anyone used this for checking balance rates? i suppose its pointless just to replace the bad injector? do all duramaxes have this problem?

[PontiacMatt72]

You have an LB7 duramax, they are the first generation of Duramax engines. they have an issue with their injectors... can't recall exactly what the deal is but something about the injector cups. The LB7 is the only duramax engine that you have to remove the valve cover to replace the injector. The LB7 is a good engine, but this is a common problem.

As for injectors going bad - my LLY duramax has stock injectors, 200k miles and still hangin in there... all other Duramax engines (besides the LB7), it's rare for them to have injector issues.

"So why do these injectors fail? Ball seat erosion or cracked bodies. The exact causes of the failure of these two areas are still up for debate.

What happens if you keep driving with bad injectors? Well if they are leaking fuel into the oil, you can cause premature wear or even failure of a lot of the bearings in your engine. So just don’t do it.

Does this happen on other engines? yes, injectors go bad. But nothing at the scale of the LB7s. Its uncommon on other models."

LB7: 2001-2004.5
LLY: 2004.5-2005
LBZ: 2006-2007.5
LMM: 2007.5-2010
LML: 2011+

The engines are all very similar, but have changes from one generation to the next. LLY's had head gasket issues. LBZ's were very good engines. I'm not as familiar with the LMM and LML. but the LB7's are the ones with injector issues. Not saying that others never will have injector issues, but it's MUCH less likely. also, balance rates don't really tell the whole story... but are a good indicator.
Here's a good read on how to go about this issue you're having:

"If you are experiencing any of these symptoms on your LB7 yes your injectors could be bad.

Smoking at idle
Rough idle
Raw diesel smell
Poor MPG
Reduced power
Knocking sound.
Fuel in oil

If you suspect that your injectors are bad first perform a balance rate test. There are a couple of aftermarket canned tuners that do this. Canned tuners are tunes that are not custom so anything besides EFI Live or HP tuners. EFI live will also perform this test as will other scan tools and of course a Tech II.

To perform the test get it up to operating temperature then when at idle in park if any of the balance rates are +/- 4 then you have something going on in that cylinder. You can also do this in drive with the park brake on. If it is +/- 6 then you have something going on. And when you hit the throttle they will all go to 0 this is normal.

If you have a balance rate out of spec, it means either a compression loss or bad injectors. On a stock truck its usually injectors or possibly an unseated injector cup. Take it to the dealer and have a return rate test performed. They should know what to do. If it is on a modded truck (big turbo ETC) it could be and unseated injector cup, bent rod or cracked piston.

The injector service policy is just that, and injector service policy. Its not a warrenty therefore it does not follow typical warrenty procedures. Your injectors are covered for 7 years or 200,000 miles from the delivery date.

In order for your truck to qualify it must fail the return rate test, balance rates mean nothing. If you think the dealer is screwing you ask for a printout of the results. Then show them to us and we canhelp you.

If your truck qualifys, the dealer is to replace all 8 injectors at no cost to you, not even the $100 warrenty fee because it is not a warrenty.

Now many dealers are also retards and will either try to screw you or they are just dumb. If you think one dealer was wrong, get a few other opinions from other dealers.

Now if your truck is out of the limits for the special service policy you have three options.

1. Get raped by the dealer $4,000-$5,000
2. Have a reputable shop do them
3. Do them yourself, its really not that hard and Bosch Remans from Partszoneonline are only $199 each. Make sure you use Bosch remans others have been failing. And if you do use others. Do not use Pensacola Diesels."

Good luck, hope this helps. let me know if ya have any more questions!

[ry57pont]

Thanks for all of the info, it helps! the only symptom i have is (i think) excessive smoke at idle, it seems only to do this when warm. i was going to run some power service injector cleaner through it and see what happens. the oil seemed to be blacker than i remember on the last oil change, but did not stink like fuel.

[ponjohn]

I looked up the procedure out of curiosity once and it was not as bad as I anticipated.

Google it, the process is not beyond the capabilities of the average car enthusiast who does most of his own work.

[PontiacMatt72]

ry57pont, the injector cleaner might help but i'd be surprised if it completely fixes the issue. worth a shot-cheap enough and aint gonna hurt anything. but long term, i spect it won't fix anything.

ponjohn, no replacing injectors is not about the capabilities of a car guy. as long as you are at least a little mechanical savvy and have patience and time, and pay close attention, it's a managable job. these engines are kind of like a puzzle up top, with all kinds of electrical, fuel lines and cooling lines, and tubes and brackets... just have to pay close attention, and pictures as you go help a lot!

I replaced the headgaskets on my truck (LLY) myself. huge job, but i was able to do it and saved literally thousands of dollars by doing so. cost me around $1200-1300 to do it myself, as opposed to $3000+ to pay a shop to do the work. I spect it would be similar for replacing these injectors, as a lot of the money is eat up in man hours to get stuff on top of the engine off and out of the way.
It took me ~17 man hours from the time i popped the hood til the time i got the heads off the engine and on the bench. course this was my first time tearing into a Duramax, and i was taking my time, takin pictures, tryin to figure out which piece had to come off at which time, etc...