I have a LLY Duramax with about 6k on it now. I have no aftermarket items on it at all, its bone stock, at least until I fix this problem.

After about 30 minutes of freeway driving, the truck sporadically will stutter and spew both black and white smoke out of the exhaust. Its so bad that cars behind me brake and swerve. The truck loses power and makes a god awful noise like a valve is slapping, and the truck shakes and stutters.

It has now been in the shop 5 times, but the dealer cant seem to replicate the problem, so I get it back and it acts up again after lengthy freeway driving.

I had the truck in one dealership in Monterey, California, who told me that some of the injectors on the LLY motor were for the 2003 Duramax and are slighty smaller in diameter than the injector sleeves. The mechanic told me that when the engine heats up, the injector sleeves get slightly larger and allow diesel and oil to dump into the crankcase, thus causing the stuttering and smoke issues.

When I took the truck back to the dealer that I bought it from, the state that unless they can duplicate the problem, or it shows up as an ECU error, the cannot and will not open up the engine to check the injectors.

I have two questions I guess.

Has anyone else had this problem with LLY engines AND can anyone give me a suggestion on how to get this issue fixed. I live in California which has a new car Lemon law, but I understand it has to be a well known and wide spread problem with a particular model of car before that law takes effect.

Any suggestions?? Please help in anyway you can.
http://www.dieselplace.com/forum/images/smilies/confused.gif

If you are in california then check around on here for good mechanics. There are several such as socaldieseltech that may be able to help.

I along w/many have had this problem. See post New LLY stumbles knocks & smokes. I added stanadyne additive and took care of the problem. Bad fuel was the culprit.

i too had this problem at 750 miles . stanadyne took care of the problem . i now have 5000 miles and am not using stanadyne anymore. contact socaldieseltech he will give you his honest opinion .

Hmm, well I just today had a heavy smoking issue. No shaking or any thing. I think I heard an aditional ticking noise. It was smoking bad like you said with cars breaking and the whole freeway getting smoked out. But I didn't have a shaking or any performance loss. I pulled over shut it down, looked things over fired it back up and the heavy smoking was gone???? It did still have small amounts of black smoke puffing out but that is it. I'm taking it in tomorrow morning to be checked.

I have been buying my fuel at the same truck stop sence I got it and I am at 1/2 full now from a full tank. The oil looks fine and the level is one notch below the F mark. The oil has about 500 miles on it. Thye rig has alomost 5K miles total.
I will post up what the dealer says...from reading this post I'm not expecting much but I hope they do find something too fix:confused:
Burt

http://dieselplace.com/forum/showthread.php?t=13033 here you go.......have a few pages to read.....

Diesel Man, I have just experienced this stutter/bucking problem yesterday morning. After letting it worm up for 5-6 minutes, driving for 10 minutes to get to the freeway as I waited for the light to change the ideal was ruff (stutter) as I got on the freeway I layed into the peddle, I could see some smoke but not real bad. still seems to run fine, but seems like the engine has gotten louder (injecters, pump etc.) I'm not sure witch. I have 12,000 on my 04' LLY and this is the first issue i'm having. And yes I do use Stanadyne and fuel filter was changed 2500mi ago. I'm hopeing it's not serious but would like to nip it in the bud now before I make a appt. to go see socaldieseltech.

Thanks,

Jim

Taken from a different thread, same issue.

Black and white smoke
<HR style="COLOR: #d1d1e1" SIZE=1><!-- / icon and title --><!-- message -->This is the same problem that mine had sporadicly. I originally bought mine late July and first reported the problem on 8/5/04. It had been to the shop 4 times until they finally determined that it was the injectors 2,3,4 that needed to be replaced.

The extra ticking you are hearing is probably the engine choking on the excess fuel it is getting because of the injector going bad. The dealer will probably not see any codes, however, GM has been having problems with injectors 3 and 4 on certain LLY's. They were checking the flow rates on mine and everything seemed fine when the truck wasn't acting up. The main obstacle is GM restriction policy on the injectors, meaning that the dealer needs to identify which injector is acting up before they can replace.

I hope it doesn't take as long as mine did for them to figure your out. The last time mine was in the shop was 1 month to the day and that is when they replaced the 3 injectors. Since then, no problems and I couldn't be happier with my truck.

The billowing black smoke doesn't sound like an additive is going to help so make sure they test drive your truck long enough to get it to act up.

Good luck,

Cory

Further info: When the white smoke comes do you hear a pinging sound?
Does it feel like the engine is running on 6 cylinders or so? I was a hair close to having GM buy back my truck because it was taking so long to fix and actually had the BBB get involved since it fell into the Lemon Law here in CA. I actually settled with GM for an extended service contract and maintanence contract for my troubles in getting this truck fixed.

I had to do most of the diagnosis myself since it wasn't acting up regularly. I actually videotaped the problem happening, billowing black smoke, choking engine, white smoke followed by a pinging sound and took that in with the keys and had them fix it. That is when the ended up having the truck for 1 month. When they pulled off my #3 and #4 injectors they said it looked like they were machined wrong. Don't know what that is supposed to mean, however, there are many with the #3 and 4 injectors being the culprit.

I did hours of research on this and other sites and what was sad is that the stealers tech finally asked where I was getting my information. So I gave him the websites so that they could educate themselves.

Anyway, it took the availability of the copilot for the diesel engines until they could identify the bad injectors so hopefully they can have it connected when the truck acts up. Mine was sporadic and started to happen more often towards the end. Ultimately it is a very frustrating issue to deal with and I hope your gets fixed soon.

Cory
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I didnt think of videotaping it, thank you very much. I just went to the dealer for the 4th time, he said that he only had a record of me being there once before, until I showed him all of the service receipts I had kept. Nevertheless, he said that he wouldnt look at it because there were no service codes showing that anything was wrong. Im going to try another dealer tommorow.

put some standyne in that thing.....

^ what he said ^