I bought my truck about one month ago and have 1,200 miles on it so far. Fantastic truck, but I have a couple of small concerns as a new diesel owner. ):h
Since I have purchased the truck I have noticed popping sound which I can best describe as sounding like popping popcorn. It is most prevalent in drive-thrus, at idle, and I can only hear it when the windows are down or when I am standing outside while the truck is at idle. Seems to disappear with throttle.

I read the majority of the threads in this forum but didn't see anything exactly the same. Is this the injector issue that is mentioned throughout, or do I need to have the truck flashed, or both?

5150,
I'm in the same situation as you...new 2005 with about 1100 miles with sort of a ticking or tapping sound at idle. The service dept at the dealer told me it was normal. I also have a friend with a 2004.5 (LLY) that said his did the same thing when it was new and the dealer told him it would go away with time. My friend now has 9000 miles and no longer has the noise. I'm not sure if this is the same noise you're describing but it sounds similar. On mine, I seem to hear it more on the driver's side but only when the engine is warm.

Just out of curiosity, what kind of mileage are you seeing? Alot of my friends with the LB7 engine and no emissions are getting much better mileage than I've seen. The best I've seen was 15mpg, but lately it's been more like 12mpg.

It's normal........it freaked me out to when I first got mine, but these guys straightened me out.......:ro)

If there is no white smoke and surging of the truck, then it is normal.

busta, you state that others with the LB7, no emissions, are getting better mileage. this may be so. i have a muffler shop going to help me convert mine. for the same price of ordering the down (intermediate) pipe, he will cut my cat off, place flanges on it and flange another 3.5 pipe in place. this way, if i ever should need the cat, i can go under the truck and bolt it on myself. He is only charging me $100 for this to be done.

I noticed the same thing the other day on my 05 with about 1000 miles on it. Not really noticable unless you're someplace the sound can reflect back to you, like in the garage. Doesn't sound like anything to worry about from what I gather here.

Normal

Response to Busta,

Mileage seems to be a bit low recently, but I WAS taking it easy during the break- in period. The OIC says about 12.5 MPG right now, but I'm not really too concerned because it has been all stop and go city driving under cold conditions. Haven't seen a bit of smoke and most of the driving has been done with a relatively cold engine temp (most trips have been short ones and I've heard MPG increase noticeably after the engine has warmed up). I've seen as high as 18-19 with extended drives at an avg of 75 MPH. Even climbing grades in the mountains it has been impressive (16 MPH) with some 4x4 High driving in the snow. The overall trip, 200 miles from the valley to 7,000 ft in elevation -- and then back again, I averaged 18 MPG. I wasn't disappointed given a new truck with a new, tight engine.

It seems to come and go. If I understand it correctly, it is bubbles in the oil going through the pump and when they come out of the pump, they pop....like popcorn...

The infamous Duramax Tick,Tick,Tick http://www.dieselplace.com/forum/images/smilies/exactly.gif

Normal (sounds more like the clicity click of an old fashioned typewriter or a loud electric relay).


Cheers